Building With Large Clay Blocks

DETAIL Practice

Building with

Large Clay Blocks

Details

Products

Authors:

Theodor Hugues, Prof. Dr.-lng., architect Chair of Design, Construction and Building Materials, Technische Universitat Munchen Klaus Greilich, Dipl.-lng., architect Christine Peter, Dipl.-lng., architect Drawings:

Editors for Detail lna Philipp, Dipl.-lng. Anna Werth, Dipl.-lng. Secretariat:

Marga Cervinka

Editing and proof-reading: Nicola Kollmann, Dipl.-l ng.

Andreas Gabriel, Dipl.-lng., architect Translators (German/English): Gerd H. Soffker, Philip Thrift, Hannover <e> 2004 lnstitut fUr l nternationale Architektur­ Dokumentation GmbH & Co. KG

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They represent typical solutions which must be coordinated with the respective boundary conditions and requirements, the relevant statutory instruments, standards and manu­ facturers' information valid in each specific, individual case. Neither the authors nor the publisher shall be liable for any claims for damages arising from the content of this book. Decisions relating to the construction, con­ struction law and building performance char­ acteristics are based on the situation in Germany and the D IN standards plus- if already introduced- the EN standards valid in Germany.

DETAIL Practice

Building with Large Clay Bloc ks

Theodor Hugues Klaus Greilic h Christi ne Peter Contents 8 I ntroduction 1 1 House A

1 2 External wal l , rendered plinth 1 6 External wal l , concrete p l i nth 20 External wal l, window

22 External wal l , window and c lay hollow pot floor 24 Double-leaf party wall

26 Load bearing and non-loadbearing partitions 28 Clay hol low pot floor

30 Double-leaf party wall and c lay hol low pot floor 32 External wal l and u nused roof space

38 Double-leaf party wall and c lay-tile roof 41 House B

42 Non-insu lated external basement wall

44 External basement wal l with peripheral insulation 48 External basement wal l with c avity i nsulation 50 Masonry external basement wal l

5 2 External basement wal l made from lig htweight c lay bloc ks

56 Rad iator recess, window with rol ler shutter 62 External wal l and converted roof space 68 Chimney

70 Partition and false wal l concealing servic es 73 Princ i p les

74 Clay brick and bloc k formats, dimensional tolerances

76 Masonry bonds

78 Dimensional coord ination 79 Structure and constr uction 83 Plaster/Render on c lay masonry 91 Supplement

Bauen mit groBformatigen Ziegeln, a book of practical exercises and the forerunne r of this book, ori gi nate d at the suggestion of the Munic h-base d Ziegelforum e .V. The graphic layout and the production of the original e d ition was c arrie d out at the office s of Sc hwe i ge r Wi nsc he rman, also in Munic h .

The authors are grateful to the assistance give n by Dr.-lng. Be rnhard Be hringer (str uctures) and Dr.-lng. Pete r Roe ke (plaste r/re nder and masonry tec hnology) .

Building with lar ge c lay bloc ks

In or der to i l l ustrate the problems and relationships, two, basically sim ilar, terrac e house types, A and B, wer e devised . These do not c laim to be spec ial in any way but rather are intended to represent the "standard c ase". The d iffer ences between the two house types lie in the degree to whic h the i nter ior space is used as wel l as the building methods and building mater ials employed .

A

is a simple house . A has no basement and the roof space is not used as living acc ommodation. The intended high degree of self-build involved is helped by omitting the central heati ng and hot­ water systems, the use of clay hol low pot or timber joist floors, and the use of conventional building elements. The separate electr ic or gas-fired heat­ ers required are placed in front of the wal l .

Cold roof space No basement Raised ground floor High degree of self-build

Longitudinal loadbearing walls Timber stairs

Minimal chimney

B

is a more elaborate design. B has a basement and a roof space for use as living accommod a­ tion. Solid rei nforced conc rete floors and central hot-water heating and hot-water supply systems call for a hi gher stand ard of construction, likewise the windows with roller shutters. The use of ex­ perienced contractors is highly advisable. The couple roof is supported on abutments monol ithic with the topmost rei nforced conc rete floor and pro­ vides a roof space free from intermed iate columns. Easy acc ess for handicapped occ upants is guar­ anteed by having the ground floor at th e same level as the surround i n g ground .

House A

1 2 External wal l , rendered plinth 1 6 External wal l , concrete plinth 20 External wal l , window

22 External wal l, window and c lay hol low pot floor 24 Double-leaf party wal l

26 Loadbearing and non-load bearing partitions 28 Clay hol low pot floor

30 Double-leaf party wal l and c lay hol low pot floor 32 External wal l and unused roof space

Exte rnal wal l, re nde re d p l i nth

Ve rtical se ction through fo undation and plinth

a 12 DF b , " ; , , , , , ; , , , , / , , ,, , , , ,; . D a

Use an excavator to dig the tre nche s for fo undatio ns i n stab le subsoils. The width o f the fo undatio n is the refo re dete rmine d by the width of the excavato r b ucket and must also be checke d with re spect to the permissible beari ng pre ssure . The nece s­ sary depth to preve nt frost heave (min. 800 mm, in ex­ pose d locatio ns as much as 1 200 mm) can be achieved with a strip fo undatio n of ade quate de pth .

D b

Build a plinth wal l on the levelling bed joint on the plain co ncrete (grade C 1 2/1 5) foundation and prote ct this wal l agai nst saturatio n o n both sides.

One approach we l l te ste d fo r re nder makes use of a waterproofi ng syste m made from an elastic sealing coat­ ing. Apply a suitable fi l le r to achieve a smooth surface and then paint o n the coat­ ing with a b rush in seve ral layers to achieve a minimum thickness of 2 mm; o n the out­ side apply a coat of p laste r­ ing mix gro up P I l l suitab le for p l i nths.

In o rde r to ensure that wate r running down the facade drains c le ar, both wate rproofing and re n de r co ntinue to the outside e d ge of the fo undatio n via a rounde d corne r fil let.

The surrounding strip of coarse gravel re duces the amount of wate r splashing up o n to the p l inth. D e

Spread a layer of hardcore ove r the excavation betwee n the walls to preve nt capillary action and permanent satu­ ratio n fro m unde rne ath, and to provide re l ief for a te m po ­ rary b uild-up of wate r. This layer should consist of 1 50 mm of coarse -graine d , c lean

gravel ( D I N 1 81 95}, ideally grad ing curve 1 6/32 , which is readily co m pacte d b ut is sti l l sufficiently pe rmeab le . In o rder to preve nt co ncrete see page whe n casting the ground floor slab, cove r the hardcore with a sheet of 0 . 2 mm po lyethyle ne . D d

To protect against mo isture rising through cap il lary actio n , a continuous damp­ proof membrane (dpm) is re quire d . The dpm and the damp-proof co urse (dpc) i n the wal l must be jo i ne d to gethe r.

I n o rde r to minimise the d iffe re ntial settle ment betwee n wal l and ground floor slab , careful co m pac­ tion of the subso i l and the anti-capillary hardco re is necessary. lt is he l pful to cast the floor slab as late as possib le . The floor water­ proofing, assuming non­ hydrostatic pre ssure and a mode rate load i n g , sho uld consist of o ne layer of b itu­ men fe lt (e . g . G 200 DD with g lass cloth inlay) or o ne laye r of b u i lt-up b itume n fe lt (e . g . V60 S4 with g lass fleece inlay) with 1 00 mm bo nde d laps: laid loose, fully o r partially bo nde d .

Bo nd the dpm unde r the floor to the dpc in the wal l with 1 00 mm ove rlapping jo ints. As these are made at d iffe re nt times, a rob ust dpc using a b itumen fe lt with a metal fo i l inlay (e . g . Cu 0 . 1 D ) i s to be re comme nde d .

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Vertical section through foundation

D e

If the subsoil around the foundation trench is unsta­ b le, formwork is required on both sides of the strip foun­ dation . Setti ng up the form­ work in turn requires a work­

ing space of 500 mm. I n addition, the sides o f the excavation must be sloped back ( 60°-40° ) to suit the angle of repose of the part ic­ ular soi l .

D f

The masonry p l i nth wal l con­ structed on the foundation must be waterproofed and the waterproofing must be protected agai nst mechani­ cal damage. This can be achieved by means of, for example, corrugated bitu­ men sheeting or synthetic studded sheeting.

Backfi l l the foundation trench in layers and com­ pact the backfi l l i ng material inside and outside simu ltane­ ously.

O g

Build the ground floor slab i nto the masonry p l inth . I n order to accommodate stresses due to d ifferential settlement, the slab must be reinforced, at least around the edges.

Covering the anti-capil lary hardcore with polyethylene sheeting i s the simplest approach. However, damage caused by the reinforcement or while casti ng the rein­ forced concrete floor slab is a risk here (see p . 1 2 , b) .

D h

One key advantage of the rei nforced concrete ground floor slab is that the junction between the damp- proof membrane (dpm) and the damp-proof course (dpc) is not vulnerable to settlement. The continuous dpc in the wal l at the same level, to­ gether with the standard plinth height of approx. 300 mm (DIN 1 8 1 95), deter­ m i nes the position of the ground floor slab above the surrounding ground. Water­ proofing agai nst ingress of moisture from the side "must be desig ned to continue up the wal l for max. 300 mm above ground level in the standard case in order to guarantee suff icient adjust­ ment options i n the ground level. U pon completion , this d i mension should not be less than 1 50 m m . " ( D I N 1 81 95 part 4 )

D i

The moisture-resistant render to the plinth continues to the top of the p l i nth. lt is possi­ ble to achieve no d ifference in texture between plinth render (P I l l} and lightweight render (P

11)

by choosing suitable plastering systems. The dpc continues to the outside edge of the structural masonry. Attach a strip of expanded metal over this problematic interruption in the substrate to provide a background for the render.

External wal l , rendered pl inth Vertical section through glazed door

D a

Set up the frame to the glazed door on the ground floor slab. Align the frame, wedge it in p lace and fix it to the floor slab with steel fixi ng cramps. Join the floor water­ proofing to the frame.

After positioning the frame, add a concrete topping with an approx. 1 0 % fal l to the outside. To prevent satura­ tion, the wood of the frame is wrapped in polyethylene sheeti ng or crepe paper. D b

The strip of insulating mate­ rial (moisture-resistant poly­ styrene, mineral fibre or per­ l ite batts) required at the wal l j unction conti nue unin­ terrupted. Add the thermal insulation after casting the concrete ground floor slab in order to avoid damage to masonry and insulation. The facing of cut c lay blocks creates a uniform substrate for the render.

D e

Place the step ( p recast con­ crete, reconstituted stone or in situ concrete) in front of the door on the compacted backfi lling but separate from the house; better still, on 300-400 mm of properly compacted gravel to pre­ vent frost heave. All surfaces should have a 1 -2 % fal l . D d

Supporti ng the open grid flooring on an angle bracket screwed into the step en­ ables the sequence of ope­ rations to be separated. D e

Tuck the sheet metal sill over the screed behind the render on both sides, screw it to the galvanised water bar and seal it at that point with a fi l let of sealing com­ pound.

D f

Fix the galvanised, close­ mesh open grid flooring by means of spacers and self­ tapping screws, or by means of bolts welded to the flooring. The floor water­ proofing must remain per­ manently bonded to the water bar.

Th is robust detail with water bar and single-rebate frame is only possible in a lobby that is not permanently heated.

Vertical section throug h entrance door

--External wall , concrete plinth

Vertical section through foundation and plinth

Da

Build the foundation only on virg in subsoil (no fill) and deep enough to prevent frost heave . Set out the external wal l exactly on the strip foundation , which is wider than the wal l and is cast directly against the sides of the trench . Set up the formwork for the con­ crete p l i nth on this. Db

Cover the anti-cap i l lary hardcore with an approx. 50 mm layer of bl inding con­ crete (grade C 8/1 0) to pre­ vent seepage of the cement slurry. This also eases the positioning of the reinforce­ ment required for the rein­ forced concrete floor slab. De

To prevent damage caused by splashing water, con­ struct the plinth with ade­ quate concrete cover to the rei nforcement and without any construction joints , and compact the concrete care­ fully.

Dd

A flush finish with the render above is achieved by creat­ ing a chamfer to the top out­ side edge of the concrete by means of a triangu lar fillet ( 1 5 x 1 5 mm) . Separation at this point is necessary owing to the d ifferent deformations. Use a galvanised, better sti l l stai nl ess steel, stop bead at the bottom of the render and fi ll the joi nt between stop

bead and concrete with an elastic sealing compound to accommodate the different changes in length due to shri nkage and thermal expansion.

De

As bitumen felt can split when subjected to bending, employ a bitumen felt with a metal foi l inlay for the damp­ proof course (dpc) i n the wal l .

I nsert approx. 50 mm thick i nsulation (mineral fibre, rigid expanded polystyrene foam) i nto the middle of the wal l to guarantee the neces­ sary thermal i nsulation.

Reduce the effect of the thermal bridge - masonry backin g/p l i nth concrete ­ by extending the i nsu lation downwards.

Vertical section through g lazed door

D f

The damp-proof course (dpc) in the wal l continues across the door open ing and must be protected for the duration of construction work. Carefu lly bond the exposed edge to the sub­ strate in order to prevent moisture seeping under­ neath .

Build in the door threshold on preformed compressible sealing strips glued i n place. O g

Lay the stiffer thermal insu­ lation on the more elastic im pact sound insulation and cover this with a separating layer before pouring the screed.

O h

Pour the floating screed without any material connec­ tion to the adjoining parts of the construction ; only in this way can the sound insula­ tion qual ities be guaranteed. The perip heral strips of insu­

lation (mi neral fibre,

expanded polystyrene foam 8-1 0 mm thick) should extend 20-30 mm above the finished floor level. Cut this off flush after layi ng the floor finish.

External wal l , concrete pl inth Plan on entrance door

D a

The " bridge-like" arrange­ ment of the open grid floor­ ing has advantages: the space between the flooring and the door reveal is wide enough to allow easy c lean­ ing, and the door frame does not need to be notched to accommodate the floori ng.

D b

After positioning, aligning and fixi ng the door, cast the galvanised water bar into the concrete. Then clean the concrete ground floor slab and remove all loose debris. To im prove adhesion, roughen the surface and wet it; alternatively, apply a bonding coat.

D c

The door frame finishes j ust above the screed and is screwed to the continuous water bar. Protect the end grain of the wood and seal the joi nt on all sides with a permanently elastic sealing compoun d .

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External wal l , wi ndow

Horizontal sections throu gh different reveals

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The masonry shoulder at doors and windows has a long trad ition . Derived from brick masonry bonds, the depth is 1 1 5 mm ( 1 /2 brick) and the width approx. 60 mm ( 1 /4 brick) . In lightwei ght clay block masonry the shoulder can be created with specials or by sawing whole blocks to suit.

This somewhat more elab­ orate detail is becoming popular again for practical and other reasons. For instance, it improves thermal insulation and moisture con­ trol aspects, and the joint between window frame and render is set back and thus protected.

I nstall the window frame, primed and given a first coat of paint, on a preformed, compressible and i mpreg­ nated seal ing stri p ; this compensates for irregu lari­ ties as it tries to return to its ori g inal size. Fill the joint between frame and masonry with a moisture-resistant i nsulating material (e.g. non­ CFC foam) . Sealing the joint on the inside with a mois­ ture-resistant seal ing com­ pound prevents saturation due to condensation water and ensures that the seal ing compound remains fully effective over the long term . Prefabricated sealing gas­ kets are available to ensure airtig htness and moisture tightness between wal l and window; the use of these helps to guarantee a good detai l .

D b

The om ission of shoulders at the head and reveals sim­ p l ifies the detail consi dera­ bly. However, many prob­ lems have to be overcome at the resulting "straight" joi nt:

- accommodati ng dimen­ sional and flatness toler­ ances ( D I N 1 8202 ) ; - fixing the frame (fixing cramps, screws every approx. 800 mm) ;

- accommodating tempera­ ture-related changes in length, deformations and movement without damage; - sealing agai nst wind (from the outside) and water vapour (from the inside) because condensation water can be expected in the joint due to the tempera­ ture d ifference of 1 5-20° ;

- protection against rain and driving rain - the most favourable values in terms of moisture control have been measured in the middle of the reveal, the isotherms are d istributed over the entire width of the reveal.

D e

If the window moves further outwards, it is not j ust the stresses on the components and their joints due to sun, wind and rain which increase. We find with hi gh-qual ity wal l insulating materials in particular that the tempera­ ture in the reveal can drop

below the dew point in the winter. The result is conden­ sation water and mould growth. I nsulation across the reveal is advisable.

Positioning the window at least 20 mm back from the l i ne of the structural wal l h e l p s t o achieve a decent return for the render.

Vertical section through sill and l i ntel

D d D f

I rrespective of the type of The lintels used here consist reveal and the position of of shal low U-shaped clay the window withi n the thick- channels in which the con-ness of the wal l , there is ventional or prestressed never a masonry shoulder at reinforcing bars are laid and the sill. Fix the standard type cast in. In structural engi-of window sill - made from neeri ng terms these bars 2 mm sheet aluminium with form the tension tie of the a fal l of approx. 1 : 1 0 - to the lintel . A "compression zone" wall with brackets in such a of masonry shou ld therefore f way that the rainwater drip be built over such shal low

projects approx. 30 mm l i ntels; use lightweight clay beyond the render. Attach blocks of compressive

L- or C-shaped sections to strength class 1 2 .

both ends of the aluminium Shal low clay li ntels are

sill for tucki ng behind the available in depths of 7 1 render on both sides. Do not and 1 1 3 mm, and widths of remove the factory-applied 1 1 5 or 1 75 mm. Without a plastic wrapping around the structural analysis, shal low

aluminium sill until all the clay l intels may be used only rendering and painting works as single-span beams up to have been completed in a span of 3. 00 m. Temporary

order to avoid, for examp le, supports during erection are splashes of lime or cement. necessary for clear spans

exceeding 1 .25 m.

Prefabri-D e cated conventionally

rein-If the desired sill height is forced or prestressed shal-not a multiple of the size of low clay l i ntels are covered blocks being used, saw by approvals.

blocks to form appropriate Sawn make-up blocks are make-up un its. required at the supports for Rustproof masonry reinforce- shallow clay lintels, either

ment laid as high as possible above or below, in order to in the spandrel panel helps match up with the bed joi nts to prevent cracking. i n the wal l (every 250 mm) .

e s

External wal l, window and clay hol low pot floor Vertical section throug h lintel and floor-wa l l j unction

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Clay hol low pot floors can be laid qu ickly without form­ work for self-build projects. Merely the beams require temporary support during erection .

The floor un its- the hol low clay "pots" - are laid on in situ concrete ribs with pre­ fabricated lattice beams

Dd

If shal low clay l intels with d ifferent widths (1 1 5 and 1 75 mm) are being used, the thermal i nsulation can be considerably improved by fitting i nsulation approx. 80 mm thick (mi neral fibre or extruded polystyrene) between the l i ntels. Position the window in l ine with this

acting as the reinforcement i nsulation.

(see p . 28) . Db

To al low hei ght adj ustments, but also to avoid excessive bearing pressure at the edge and to prevent the voids of the clay b locks being fi l l ed with concrete, provide a levell ing bed of mortar 20 mm thick. De

Lay the lattice beams of the ribs with a min. 1 00 mm bearin g on the bed of mortar and connect them together by means of an in situ con­ crete ring beam . The i nsula­ tion, about 50 mm thick, between beam and block­ work is best inserted after

casting the beam. To create a uniform sub­ strate for the render, saw a large-format clay b lock to suit.

s

D e

L i ghtweight clay channels matching the thickness of the wall, 238 mm deep and 240 mm long, serve as per­ manent formwork and pro­ vide a uniform substrate for the render. Position the insu­ lation and the reinforcement, then fi l l the channels with concrete. Th is type of rein­ forced concrete l i ntel can span clear openings up to about 2.75 m.

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D f

The use of shal low clay lin­ tels with d ifferent depths

and widths permits the con­ struction of l i ntels with shoul­ der and thermal i nsulation.

Double-leaf party wal l

D a

The sound reduction i ndex (57 dB, D I N 4 1 09) required for the party wall can be achieved with a double-leaf wal l comprising two leaves of 175 mm lightwei ght clay blocks, gross density class 0.8, plus min. 30 mm thick semi-ri gid mineral fibre i nsu­ lating batts . The batts are positioned loose and held in place by the masonry leaves.

The sound reduction index can be increased to 67 d B (enhanced requirements, DIN 41 09) and the wal l classed a s a fire compart­ ment wal l (Bavarian Building Code) by using vertically perforated clay blocks with B-type perforations and gross density class > 1 .2 . D b

Continuing the damp-proof course (dpc) across the separating joint has no adverse effect on the acous­ tic properties of the wal l . Build the leaves of the party wall i n succession , not simu ltaneously, in order to rule out - as far as possible - acoustic bridges for struc­ ture-borne sound caused by debris and mortar drop­ pings. Separati ng joint boards with an inorgan ic coating on one side, devel­ oped for dou ble-leaf con­ crete walls, can be used here to help keep the work clean.

D e

The separating joint must continue through the foun­ dation if the en hanced requirements are to be met. To do this, cast the strip

D d

I n both variations, conti nue the construction of the party wal l as for the external walls and plinths shown on pp. 1 2 and 1 6.

D e

Shear wal l s do not need to be built into the external walls - a butt joi nt is ade­ quate - when other means (e.g. flat anchors cast in) are provided at the j unction to resist the tensi le and com­ pressive forces.

O f

The separati ng joint, fi lled with elastic insulating mate­ rial , must continue through to the render and be sealed there with an elastic mate­ ria l . Stop beads, fixed with a background to the wal l , are frequently used . The joint itself is then covered with a folded PVC profi le.

The solution shown here makes use of two stainless steel stop beads along the sides; the render continues right up to these stop beads. The space between the stop beads is fil led with a closed­ cell foam profile and after su itable treatment the joint is closed off with a perma­ nently elastic sealing com­ pound.

Plan on party wal l-external wal l j unction

0

The ideal place for the rain­ water down pipe would be directly over the joint. How­ ever, it is d ifficult to fix the pipe clips securely to the soft joint material - special fixings wou l d be required .

Load bearing and non-load beari ng partitions Vertical sections through foundation

D a

If separate concrete ground floor slabs are used i n each room, this saves concrete and rei nforcement and also enables the use of d ifferent floor constructions . How­ ever, this does subj ect the damp-proof mem brane (dpm) to an increased risk of d ifferential settlement and hence damage.

b

D b

The constru ctional advan­ tages of the co nti nuous rein­ forced co ncrete ground floor slab become clear at the partitio ns.

No n-load bearin g partitions can be "carried" by a rein­ forced concrete grou nd floor

Vertical sections throu gh ground floo r slab

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De

Secure joi nts in the d p m are also necessary below load­ bearing partitio ns.

The foundation to the par­ titio n , which is not affected by frost heave and can th erefo re be shallower, is co nnected to the d eeper

Clay ho l low pot floors and non-load bearing partitio ns I sometric view of clay ho l low pot floo r

C lay ho l low pot floo rs con­ sist of beams, or rather ribs, with no n-stru ctu ral clay ho l­ low "pots" in between . The prefabricated ribs must be temporarily su ppo rted dur­ ing erectio n , but further formwork is u nnecessary.

The compression zo nes of the ribs, rei nforced as lattice beams, are finished on site with in situ concrete. Spans of 5-7 m are possi ble by using floor u n its of d ifferent depths (between 1 60 and 250 mm) and by varying the spac ing of the ribs (500 o r 625 m m centres) . A n in situ stru ctu ral concrete to pping added o n site improves the load -carrying capacity and sound i nsu latio n .

D a

In this detail the partition and the rib are on the same axis.

Vertical sectio ns through partitions

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If the partitio ns do not co in­ cide with the ribs, a rein­ forced trimmer formed by a row of concrete-fi lled "nega­ tive pots" is required .

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Dou ble-leaf party wal l and clay hollow pot floo r Vertical sectio n throu g h floor without co ncrete topping

If the structu re is not a mu lti­ ple of the size of the clay ho l low pot floo r u n its, co n­ struct make-up (end) bays. D a

With large ed ge marg ins lay flat "negative pots" and fi l l them with co ncrete to form an ed ge beam (reinforced as requ ired ) . The brick-o n­ end masonry u n its guaran­ tee the function of the sepa­ rating jo int.

The beari ng fo r the floor units, a bed of mortar approx. 20 mm thick, should be at least 30 mm deep. D b

With small ed ge marg ins between lattice beam, or rather the ri b , and wal l, fi l l the space between the floor u n its and the brick-o n-end

masonry u n its with concrete (rei nfo rced as requ ired) to fo rm a ring beam .

D e

If the ring beam has to co n­ tinue u p to the separating jo int, then it shou ld be cast

in two pieces, with the sound i nsu lation being positioned after the first concrete pou r and kept c lean with a poly­ ethylene sheet. The po ly­ ethylene sheet u nd erneath the mortar l evelling bed pre­ vents cement slurry seeping into the separating jo i nt.

D d

A concrete to pping co nsider­ ably improves the load -car­ rying capacity with regard to imposed loads and light­ wei ght partitio ns, but also the acoustic perfo rmance of the clay ho l low pot floor. I n terrace houses - assuming no high demands o n impact and airborne sound insu la­ tion withi n the same residen­ tial u nit - a carpet with good sou nd insu lation pro perties cou ld well be adequate.

iD

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Vertical section th rou gh floor with concrete topping

r

b

.

d

External wal l and roof space not used as living accommodatio n Vertical sectio n through eaves, purl in roof and clay ho l low pot floo r

a

D a

The floo r u n its should bear max. 30 mm on the external wall, or rather mortar level-ling bed . They are jo ined to gether and to the ribs with an in situ co ncrete ring beam.

D b

lt is easy to co nstruct a ven-tilated, "co ld" roof space and this presents no pro b-lems in terms of insulatio n ,

mo istu re co ntro l , etc. The

roof is simply an "u mbrel la"

over a heated, heavyweight

structu re. lt is l ittle trou ble to provide the to pmost floor with thermal insulatio n . This type of floor is airtight and , thanks to its mass, stores

heat wel l .

Ventilation in shal low-pitched roofs _{( < 1 0°) takes} place from eaves to eaves (min. 20 mm net per m) ,

controlled by wind pressure and wind suction. On steeper roofs ventilation at the rid ge

or near it (e. g . i n the seco nd

row of tiles from the to p) is necessary.

As it is not possible to pre-vent dust and driving snow fro m entering the roof space throu gh the jo ints in the roof covering, this limits the use

of the roof space.

De

Co nnect the eaves pu rl in to the ring beam with ragbolts. Th� ragbolts are inserted into correspond ing pockets which are fi lled with con-crete after aligning the pu r-I in.

Vertical section throu g h eaves, pu rlin roof and clay ho l low pot floo r

D d

The thermal insulation laid over the clay ho l low pot floor

is afterward s covered with a

screed , which has joints

arou nd the ed ge and every 25-40 m2. The screed serves

as a wearing cou rse,

pre-vents d amage caused by any mo istu re present in the roof space and also acts as fire protectio n .

D e

When using interlocking clay

roof tiles, check the length of the rafter to ensure that it is su itable fo r the cover length of the particu lar ti les chosen. D f

"Negative pots" act as per-manent fo rmwork fo r the

stiffening transverse ri b .

O g

Gable wal l s, if not su p po rted by masonry piers or

cross-walls, must be fixed to the

roof stru ctu re ( D I N 1 053) ,

e . g . by means of galvanised

steel flats or ru stproof

rag-bolts. The jo i nt between the

final rafter and the maso nry

of the gable must be able to transfer the forces involved .

D h

After setti ng u p the rafters, finish off the to p of the gable wal l with a screed , flush with the rafters. Cover this with a flashing of, fo r examp le, fu l ly bonded bitumen roofing felt V 1 3 . The 1 0--1 5 mm deep cou nter battens of AW 1 00 p lywood prevent water co l-lecti ng,behind the tiling bat-tens. The cover width of the clay verge ti les must co in-cide with the width of the bu i ld i n g . � ' ' ' h s s 12 DF

External wall and roof space not u sed as l iving accommodation Vertical sectio n through eaves, p url in roof and clay ho l low pot floor

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Vertical section through eaves, purl in roof and clay ho l low pot floor

D a D d

The roofing felt u nder the The roofing felt below the

tiles is a water-repel lent but tiles co ntinues over the to p e

vapour-permeable material of the masonry, to which it is

which remains stable despite bonded . The thin counter temperature changes, e.g. battens prevent water collect-mesh-rei nforced polyethyl- ing behind the ti ling battens. ene. lt prevents the ingress

of d ust, rain and d riving D e

snow. Stretch it taut, secure Use the two-piece bent

it with co unter battens and sheet metal verge when, for ensure that water can d rain example, the width of the away at the eaves - id eally build i n g is not a multiple of

into the gutter (see p . _{36, d).} the cover width o f the

inter-locking clay tiles. Otherwise,

D b _{special o r cut tiles are}

neces-As on p. _{32, flat-pan tiles are} sary. used here as wel l . The roof

pitch of approx. 3JO chosen D f

for our example is suitable Connect the masonry gable for virtually all types of clay to the roof structure by roof tile: bullnose tiles as means of cast-in ragbolts. crown or slip ti ling, pantiles, Bracing i n the p lane of the interlocking tiles with single roof i s thereby necessary.

or do uble tro ughs, right u p

to the ever mo re accurately interlocking varieties.

De

Determ ine the cross-sec-tional areas of g utters and

downpipes based o n the size of the roof area to be d rained . C reate the fal l of the gutter - min. _{1 mm/m}

-by bending the g utter s

b rackets to suit.

External wal l and roof space not u sed as living accommodatio n Vertical sectio n throu gh eaves, pu rl in roof and timber joist floor

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The timber joist floor over the u pper storey represents an inexpensive and , for self­ bu i ld projects, simple form of construction . Virtually any depth of thermal insu lation

is possible with loose mate­ rials, and easi ly laid . lt is possible to improve the low heat storage capacity by using heavy loose materials or by laying solid bricks 50-70 mm thick below the loose materia l .

O b

The stability of the bu ilding in all d irections is guaran­ teed by joining a l l load bear­ ing and shear walls to the floors with proper structu ral connections. If ring beams are provided , the walls can be regarded as being su p­ ported on all four sides; the floor joists only need to be held in position in that case . Line the joists pockets in the masonry with a moistu re­ resistant thermal insu lation , at least at the end of the joist, preferably on al l sides, to reduce the risk of d amage by condensation water.

De

The airti ght connection between the 0.2 mm poly­ ethylene sheet and the wal l i s achieved with ad hesive and by using a clamping batten pressed onto a pre­ formed compressi b le seal­ ing strip along the wal l . The most secure connection is when the polyethylene sheet is wrapped arou nd a batten and screwed throu g h this into the wal l .

O d

G lu e the roofing felt below the tiles to the nai led sheet metal. The perforated sheet metal bent into an i nverted V-shape ensures ventilation below the clay roof tiles. D e

Even if the plastering work is carried out before l aying the timber joists, the u neven­ ness of the wal l and the ring beam must be evened out with an ad aptable "system" which closes off the joints airtight.

This can be achieved with a batten nailed throu g h a preformed compressi ble sealing stri p . Fill the void between joist and wal l com­ pletely with an u ncompacted mineral fibre material.

After fi lling the bays between the joists with a loose insu lati ng material, nail on the actual flooring mate­ rial . The gaps at the ed ges, necessary to al low move­ ment of the flooring, can be covered with a triangu lar fi llet.

D f

Connect the gable wal l to the roof constru ction in such a way that forces can be transferred .

Vertical section throu g h eaves and timber joist floor

e

6 DF

Dou ble-leaf party wal l and clay tile roof

D a

If th e floo r jo i sts are paral lel with th e wal l , th e slender, tall party wal ls must be secu red with ring beams if th ey are not co nnected to th e braced roof stru ctu re.

D b

Connect th e u nsu p po rted tops of the walls to the braced roof structure such th at forces can be transferred . Continue th e separating joint th rough to th e roof even in a roof space not u sed as living accommodatio n .

D e

Th e roofing felt h eld by th e counter battens - essentially taut but sagging sl ightly due to temperatu re ch anges and extension of th e material - is bond ed to th e mortar level­ ling bed .

D d

lt is advisable to replace th e tiling battens by galvanised steel angles. A clearance of 1 0-20 mm between the angle and th e to p of th e masonry enables th e roof structu re to defo rm without restraint. Fill the space between the angles with an inco m bu sti ble, vo lu­ metrically stable insu lating material . If th e roof space is to be co nverted into living accommodatio n at a later date, th e separating jo i nt must co ntinue u p to th e roof covering and th e tiling battens must be d ivided .

House B

42 Non-insu lated external basement wal l

44 External basement wal l with perimeter i nsu latio n

48 External basement wal l with cavity i nsu latio n 50 Maso nry external basement wal l

52 External basement wal l made fro m lig htweig ht clay b lo cks

56 Rad iator recess, window with ro ller shutter 62 External wal l and converted roof space 68 C h i mney

No n-insulated external basement wall Vertical sectio n through co ncrete plinth

c d b " " � � _{/ " ' /} ' ; , ; , , , " " , _{, / , , , , / ,} a D a

C ast the upper, and rein­ forced, part of the strip fo un­ d ation to gether with the rein­ fo rced concrete basement floor slab in one pour, then strike the outside formwo rk. The depth of the reinfo rced concrete basement floor slab depends on the loads from the basement part itions but sho uld be min. 1 20 mm in o rder to ensure the neces­ sary co ncrete cover to the reinfo rcement.

D b

A d amp-proof mem brane (d pm) beneath the screed is not required when the building is fo unded on a quick-d raining subso i l and neither a high-qual ity floor coverin g nor impact so und i nsulation or thermal insula­ tion is required . However, if a d amp-proof mem brane is not included , a layer of hard­ core to prevent cap i llary action is necessary . An approx. 30 mm bonded cement screed is adequate as the wearing co urse in simple basement rooms. D e

Basement wal ls constructed i n normal-weight concrete­ even if they are reinfo rced -must be waterproofed on the side in contact with the so i l . The type of waterproofing depends on the level of mo isture to be expected on the outside. D I N 1 81 95 part 1 tab le 1 categorises types of waterproofing accord i n g to moisture load and so i l type. Moisture in the so il must always be reckoned with . Furthermo re, in cohesive so ils and/o r on sloping sites the presence of water in dro p let/l iquid form is to be expected . This means that waterproofing to protect against non-hyd rostatic pressure must be backed up with a drainage system

which prevents sho rt-term hyd rostatic pressure (see p p . 48 and 52) .

Special measures must be taken fo r hyd rostatic pres­ sure on the o utside.

Fo r moderate loads water­ proofing to the normal-weight co ncrete of the external basement wal l can be achieved i n various ways: e.g. with one layer of bitumen felt, bitumen bui lt-up felt, in each case with a fabric in lay and 1 00 mm laps o n a prim­ ing coat; with b itumi no us coatings in several layers; with two layers of a mineral sealing coati ng with build ing authority approval. Whereas in the case of flexible sheet­ ing good protectio n is required d uring backfil l ing and the upper "exposed " end must be sealed, the mineral coati ngs cannot brid ge over any cracks owing to their inherent

brittleness. D d

The ground floo r co nstruc­ tion in this example includes thermal insu lation to i nsulate agai nst the unheated base­ ment. Take the presence of heavy co ncentrated loads into account when choosing the insulating material. Place the impact so und i nsulation beneath the thermal i nsula­ tion and around the ed ges -without i nterruption - in o rder to prod uce a "floating" floo r constructio n . Conse­ quently, the floor finish must be fully isolated as wel l ; con­ tinuing the ed ge insulating strip up to finished floo r level is advantageous.

g

e

Vertical sect io n through co ncrete lightwell

De

Lightwells of in situ co ncrete "hang" on t he basement wal l and must b e co nnected to t his - possibly wit h fo lding

anchors which are placed i n t he formwork a n d , after strik­

ing t he fo rmwo rk, are ex­ posed again and fo lded o ut into posit io n .

Df

The base of t he lightwell can be covered with a coarse gravel , which wi l l have to be rep laced from time to t ime­ assuming a q uick-draining subso i l and backfi lling.

Dg

The to p edge of t he lightwell in t hi s example is reduced to match t he size of t he grat ing so t hat any paving or grass can co ntinue right up to the edge of t he frame. Cast t he top edges of t he lightwells later to match t he level of ext ernal works and external doors, also wit h falls if neces­ sary .

Dh

If t he t hermal insu lat io n is attached to t he u nderside of the ground floor slab, this results in a thermal bri dge to t he external wall. This has to

be minimised by including insulat io n within t he t h ick­ ness of the wal l which ex­ tends down at least to t he

underside of the ground floo r slab.

External basement wal l with perimeter insu l ation Vertical sectio n throu gh prefabricated plinth

d

12 DF

D a

The basement wal l can also be waterproofed by using impermeable co ncrete. This type of concrete is achieved with min. grade C 25/30 concrete havi ng a limited water penetratio n depth (max. 50 mm) , and by ad­ hering to the requ ired water/ cement ratio and grad ing curves. Rei nfo rcement to prevent/limit cracking is essentia l . Carefu l com pac­ tion and su bsequent treat­

ment is requ ired . The mini­ mum thickness is not pre­ scri bed but should not be less than 250 mm.

External perimeter -thermal i nsu lation to compo­ nents in contact with the so i l is produ ced from c lose-cel l extrud ed , polystyrene foams or cellu lar g lass , which absorb little o r no mo istu re and are attached to the waterproofed basement wal l with dabs o f , fo r example, bond ing mortar.

Cover the i nsu lation with corrugated bitu men sheet­ ing o r studded flexible sheeting to protect it against mechanical d amage du ring backfi lling.

D b

Fou ndatio ns to small houses are often simpl ified and co n­ structed together with the grou nd slab as a raft fou nda­ tio n , which must be pro perly designed and reinforced

accord ingly. Thickening of the slab may be necessary u nder heavy loads, e . g . i ndi­ vidual co lumns, i ntermed i ate load bearing wall s with larger openings.

If the raft fou ndatio n is constructed from imperme­ able concrete l ike the exter­ nal wal l , seal the jo int between the two co ncrete compo nents with a water­ sto p o r water bar.

D e

A heated basement forming part of the living accommo­ d ation requ ires an acoustic­ a l ly and thermally insu lated , waterproofed floo r slab with a flo ating screed . To prevent satu ration of the impact sou nd insu lation by the co n­ structio n mo isture i n the concrete floor slab, provide a separating layer of, for exam ple, po lyethylene sheeting.

D d

Protect the transition between basement wal l and external wal l - the p l i nth - agai nst splashing water and mecha­ nical d amage by means of precast co ncrete or natu ral stone panels. Su p port these on cast-in ancho rs. Finish the render at a sto p bead and close off the jo i nt to the pl i nth with a permanently elastic sealing co mpou nd . The external maso nry pro­ jects approx. 90-1 00 mm beyond the concrete wal l . The u nderside o f the perfo­ rations in the clay blocks should be closed off at the projectio n . On the inside, reinfo rce the p laster with a textile mesh at the transition between the two materials.

12 DF

5 DF

e

Vertical section through rendered p l i nth

D e

Lay the insulation below the reinfo rced co ncrete base­ ment slab on a fi lter gravel or layer of blinding and cover over with a separati ng layer. C ast the basement slab o n this. A covering o f lean-mix concrete is advisable.

When calculating the heat­ ing requirements allow for small heat losses via the thermal bridges at the strip fou ndatio ns u nder the exter­ nal walls and load beari ng wal ls.

D f

Co nti nue the mineral sealing coating beneath the external wal l and jo i n it to the flexible sealing coating o n the o ut­ side of the external basement wal l .

O g

The b u i lding trade is d ivid ed on the best method of con­ structin g a rendered plinth on properly fixed perimeter insulation batts. At least two coats of impermeable render (suitable fo r plinth work) will be necessary on splatterdash and a galvanised back­ gro u nd, add itional ly rein­ forced if necessary. Whether the normal rend er thickness of 20 mm is suffi­ cient fo r this type of detail is q uestionable. The render that extends into the gro u nd must be protected against lo ng-term saturatio n .

O h

D I N 1 81 95 part _{4 calls for at} least one horizontal d amp­ proof co urse (d pc) i n the internal and external walls.

The number of horizontal d amp-proof co urses is left to the d iscretion of the design team.

The damp-proof course beneath the masonry of the wall represents a precau­ tionary measure preventing mo isture rising from the co n­ crete below.

External basement wal l with perimeter insu lation Horizontal section through prefabricated lightwell

D a

Fixing a lightwel l to a wal l with perimeter i nsu lation i s not without its pro blems because the insu lation should not be penetrated or, at best, only min imally . I nd ivi­ d ual fixings using heavy-duty anchors and spacers with bu ild ing authority approval are therefo re employed . The approved ed ge d istance between ancho r and window opening must be assured .

O b

Furthermore , the "surface of the wal l " presents pro b lems. Althou gh the render to the plinth can co ntinue down into the lightwell to gether with the backgrou nd , such

small areas of render com­ plicate the co nstructio n . The area can be rendered before mou nting the lightwe l l . D e

If requested , some manufac­ turers wi l l position the rebate at the to p of the l i g htwel l externally. A n inco nspicuous ed ge is thu s possi ble. O d

Below ground level seal the jo int between the bu i ld ings with flexible sheeting. The small loop of excess mate­ rial is necessary to accom­ mod ate movemerit. The jo i nt between the bu i ld ings must co ntinu e throu gh the plinth.

Vertical section throu gh prefabricated lightwel l

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External basement wal l with cavity i nsulation Vertical sectio n through co ncrete plinth

c

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a

Da

The reinforced concrete strip fo undatio n req uires fo rmwo rk to both sides. Cover the anti-cap i l lary hardcore layer, included for add itional security , with a layer of b l ind ing co ncrete, grade C 8/1 0, and then cast the reinfo rced concrete ground slab on to p of that. This forms a good base for worki ng in d ifficu lt, e.g. clayey, subso i ls d uring rai ny periods.

Drainage around the perimeter is necessary o n slo ping sites o r i n cohesive so ils.

D b

Lay the pipes, min. 1 00 mm NB, fo r the perimeter drain­ age o n a gravel bed to a fal l o f 0.5%, better 1 % , and sur­

ro und them with a filter mat in order to keep out the fin­ est so i l particles. In o rder to avoid undermining the fo un­ d ation , do not lay the d rain­ p i pe and the filter bed lower than the underside of the fo undatio n . A distance of min. 200 mm between the to p of the structural slab and the underside of the d rain­ p i pe is mand atory. De

The concrete d rainage un its protect the waterproofing against mechanical d amage and ensure that water is d rai ned away fro m the external wal l .

D d

The detail with moisture­ resistant cavity insulatio n , e.g. polystyrene o r mineral fibre batts, and an i nner l eaf ensures adequate thermal insulation and a good mois­ ture balance in heated base­ ment roo ms. lt is not usual ly necessary to include a vapour barrier o n the inner side of the thermal i nsu latio n . D e

The thermal insulation on the underside of the slab over the basement is necessary

in this case in order to reduce the thermal brid ge effect of the mono l ithic reinfo rced co ncrete co nstructio n .

D f

If complicated junctions are to be avo id ed , seal the pro­ jecting basement wal l with a dense, mesh-rei nfo rced screed . Such a detail requires a location protected fro m the weather and preferably roofed over.

D g

A co ntinuous slot in the base of the lightwel l ensures water can drain away into the quick­ draining backfi l l i n g material.

Vertical section through lightwel l and entrance door

Masonry external basement wal l Vertical sectio n throu gh rendered plinth

12 DF 11 11 6 DF 11 11 11 s 11 11 11

11

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The walls to u nheated base­ ments are bu ilt using verti­ cally perforated clay blo cks, e . g . H lz 1 2- 1 . 2-6 OF, which have a greater compressive strength but, mainly, a higher gross density.

As masonry basement walls can o n ly resist lateral so i l pressure o nce the verti­ cal load of the bu i lding is available, backfi lling is car­ ried out later, e . g . after com­ p leting the stru ctural wo rks.

A water-repellent basement wal l rend er of grou p P I l l provides the waterproofi n g . A s this rendering is relatively expensive and time-consum­ ing, is also rigid and there­ fo re vu lnerable to cracking, flexible seal ing coatings which can be rendered over may also be u sed .

Drainage mats, e . g . corru ­ gated o r studded sheeting, protect against mechanical d amage during backfi lling.

D b

Lay a damp-proof cou rse (d pc) of R 500 b itumen roof­ ing felt, better sti l l Cu 0. 1 D waterproof sheeting ( D I N 1 8 1 95) , o n the strip fou nda­ tio n and bond this to the d amp-proof membrane

(d pm) over the rei nfo rced concrete ground slab. Great care must be taken with the jo i nt where the strip founda­ tion projects beyond the basement wal l ; the provision of a rou nd ed fil let and a fal l to the outside is advisable. The dpc beneath the walls should be jo ined to the grou nd slab dpm in o rder to produce an id eal , contro l l ed horizontal waterproofing sys­ tem.

D e

The 25 mm mastic asphalt floor finish (surface finished with a smoothing compound) laid o n a special bitu men bu i lt-u p felt satisfies basic requ irements regarding ther­ mal i nsu latio n and impact sou nd insu latio n .

d

s

s

Vertical section through prefabricated lightwel l

D d

The pl inth render u p to the level of the d amp-proof course has the same com­ position and thickness as that on the external base­ ment wal l . lt is finished flush with the render to the masonry above; slit the joint between the two types of rendering with a trowel. An ang led undercut is reco mmended .

D e

Bu i ld u p the prefabricated lightwel l units o n the backfi ll­ ing separate fro m the house. This arrangement overcomes the need to fix complicated anchors i nto the masonry but does requ ire the backfi ll­ ing to consist of clean, com­ pactable material. lt is essen­ tial to compact the material carefu l ly and pro perly in o rder to reduce settlement of the free-stand ing lightwel l and hence damage to the masonry.

External basement wal l made fro m lightwei ght clay b lo cks Vertical sectio n throu gh rendered plinth

a

b

D a

Basement walls mad e fro m large lightweig ht clay blocks provide the necessary ther­ mal insu latio n fo r heated basement roo ms and all the cond itions fo r a comfortable interior climate.

A structu ral analysis must be carried o ut befo rehand to ensu re that the wal l thick­ ness co mbined with the ver­ tical load are able to resist the lateral so i l pressure over the depth of the basement.

Waterproof the wal l with an elastic coating, e.g. made fro m a bituminous material, which contin ues as a flexi ble

sealing coati ng i n the area of the rendered p l i nth. Drain­ age mats guarantee protec­ tio n fo r the waterproofi ng.

D b

The damp-proof mem brane (d pm) to the ground slab, required to protect against water held or flowi ng in the so i l du e to cap illarity (suc­ tion water, retained water, cap i l lary water), shou ld be secu rely bonded to the d am p-proof course (d pc)

beneath the masonry wal l (protectio n against capillary mo istu re) and also the ex­ ternal waterproofi ng. D e

Lay the peri meter d rainage o n a gravel bed and protect it on all sides with a filter mat agai nst ingress of fine par­ ticles.

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A nu m ber of manufactu rers produce prefabricated p las­ tic lightwells fitted with a su itable grati ng. These are ancho red in the maso nry . D e

If the reinforced co ncrete floor slab spans over the wi ndow opening, it is not necessary to provide a masonry "compression zo ne" over the shallow clay l i ntels (see p. 2 1 ) .

External basement wal l made from lightweight clay blocks Vertical section thro ugh entrance door

b

D a

The wooden threshold to the door prevents condensation water and the fo rmation of

ice in winter; the rebates and seals can continue right aro und the door. However, special precautions for this d etail are necessary, also

because it is subjected to high mechanical load s: the cho ice of a su itable species of wood , e.g. oak; the provi­ sio n of falls to the o utside; keeping o ut heavy or d riving rain by means of the close­ mesh o pen grid flooring screwed on clear of the wood ; the fo rmation of a water bar with d ri p throat to repel incoming water.

Th is latter task is o n ly ful­ filled by the botto mmost board of the o uter leaf to a very l i mited extent. To do this, the entrance door m ust be protected fro m the wind and weather.

As mechanical d amage is hardly avo idable, this detai l is not suitable for heavily trafficked areas.

D b

The build i n g of a "naturally" coo l and damp basement fo r storage purposes requires a subso i l in which d rai nage is abso l utely guaranteed . A build-up of water m ust be ruled o ut. An anti-capil lary hardcore layer min. 150 mm d eep below the floo r of so l id clay bricks bedded in sand is advisable for extra secu­ rity . The inside of the base­ ment walls should be pro­ vid ed with an elastic sealing coati ng painted over with a m ineral whitewash , l ime­ wash or mi neral paint.

12 DF

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Vertical sections throu gh partitio ns

D e

The d rawi ng shows the tran­ sition between the storage roo m with its floo r directly o n the ground and the thermal ly and impact-sou nd insu lated floor of the heated basement area. The damp-proof mem­ brane (d pm) u nder the heated area must be fixed to the water bar at the door.

D d

Partitio ns in the basement, just l ike externa l walls, requ i re protectio n against moisture rising from below.

D e

A d pm is not required below partitio ns over basement areas.

Radiator recess, window with ro l ler shutter Vertical sectio n throu gh clay ro ller shutter box

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The ro ller shutter box and the outer leaf co ncealing the floo r slab fo rm a u n ifo rm su bstrate for the render. Such boxes are facto ry-pre­ fabricated , no n-load bearing items which can carry their own wei ght over o penings up to about 5 m wide thanks to their integral reinforcement. They are approx. 300 mm deep and available fo r wal l thicknesses of 300 o r 365 mm.

D b

The mai ntenance opening cover, made from 1 2-1 5 mm BFU plywood and a layer of thermal insu l atio n , e . g . min. 30 mm rigid polystyrene foam, is screwed i nto a rebate formed by an alumi niu m angle.

lt is rare fo r any attention to be paid to the detail at the ends of the mai ntenance o pening cover; heat losses and d rau ghts are the resu lt. Co nti nu i n g the angle frame arou nd all fou r sides and jo ining it to the thermally insu lated sup po rts fo r the ro ller shutter box wou ld be necessary.

De

The 1 75 mm masonry leaf behind the rad iator recess enables the rad iato r to be mou nted in the usual way o n cast-in wal l brackets. The i nterru ptio ns to the thermal insu lation simply have to be accepted .

D d

Fit the thin wi ndow board , e . g . 25 mm natu ral stone, into chases i n the maso nry reveals and su ppo rt it o n brackets every approx. 600 mm.

D e

Cut an o pening in the masonry fo r the shutter o perating cord if a special brick with a ready-mad e o pening is not being used .

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The brush o r l i p seals to the o pening for the shutter o per­

ating co rd cannot com­ pletely ru le out heat losses at this po int.

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A clay ro ller shutter box requ ires a min. 80 mm bear­ ing, 1 50 mm on the operat­ ing cord side. Cut off the rend er sto p bead at the u nderside of the shutter box to match the clear o pening of the window.

O

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Rad iator recesses must be co nstru cted to match the masonry bond of the wal l .

Ru nning the pipes in verti­ cal slots in the external wall and weakening the sides of the recess fo r con necting the rad iato r pipewo rk was fo r a lon g time the standard solutio n . In o rder to meet the enhanced thermal i nsu latio n requ irements of newer leg is­ latio n , insu late the slots at least on the outside, prefer­ ably on three sides. Cut the slots fo r co nnecting the rad i­ ator pipework with a masonry saw.

O

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Cutting the thermal insu la­ tion to fit exactly in the recess is the standard so lu­ tio n . Heat losses throu gh the no n-i nsu lated sides are

igno red ; any condensation water that does occu r here is simply d riven off by the heat from the rad iator. Wood -woo l slabs o r sand­ wich panels with a poly­ styrene core have suffi­ ciently rou gh su rfaces to provide a key for plaster.

Radiator recess, window with rol ler shutter

Vertical section through prefabricated roller shutter box

11

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"Half" roller shutter boxes are available for windows with a masonry shoulder at the window head .

A lintel flush with the ceil­ ing or a shallow clay l i ntel spans over the opening in the masonry. This deter­ mines the size of the rol led­ up shutter and in turn the hei ght of the window.

From the point of view of thermal i nsulation , operating the shutter with a winding mechanism fitted in the reveal or on the wal l is pref­ erab le to the operati ng cord . Db

I ncorporating a 300 mm c lay masonry unit (5 OF) in the 365 mm external wal l (6 OF or 1 2 OF un its) but flush on the outside creates a recess in the wal l , 1 35 mm high x 65 mm deep, above the re­ inforced concrete floor. With i nsulation at the back of the recess, this can be used for the radiator p ipework. Con­ nect the p ipes to the radiator underneath in the radiator recess. Smooth , fi l l and coat the screed . A structural ana­

lysis is required for this hori­ zontal slot.

De

Span over the radiator recess with a shal low clay l intel. The window board can be corre­ spondingly thinner in this case .

Horizontal sections through roller shutter box, window, radiator recess

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The ends of the rol ler shutter box bear min. 40 mm on the external wal l . The bond of the masonry above the shallow clay lintel must match the masonry bond of the large clay b locks of the external wal l .

D e

The masonry shoulder en­ ables the guide track for the roller shutter to be fitted vir­ tual ly flush with the render. The bottom end of the track is welded closed and rests on the sheet metal window sill. The U- or L-shaped bent-up ends of the window sill are notched to suit.

Precautions to prevent galvanic corrosion are nec­ essary if the metal of the track and the metal of the window sill are different.

Slit the joint between rendering and roller shutter track with a trowel , or fi l l the joint with sealing compound.

D f

Continuous reinforcement in the masonry, at least in the uppermost bed joint, is neces­ sary to minim ise cracki ng.