OBJECTIVES
After reading this chapter and completing the review questions, you should be able to:
■ Explain why it is useful for the building estimator to be able to prepare a takeoff of plumbing, heating, ventilating, air conditioning (HVAC), and electrical work.
■ Explain why it is useful for the building estimator to be able to make sketches of plumbing, HVAC, and electrical requirements for a project.
■ Describe how plumbing, HVAC, and electrical work are measured in a takeoff.
■ Explain how the builder’s estimator can price the plumbing, HVAC, and electrical work.
■ Explain the use of quick methods of estimating plumbing, HVAC, and electrical work.
■ Describe the cost per fi xture method of estimating plumbing.
KEY TERMS
7
E STIMATING P LUMBING ,
H EATING , V ENTILATING , AND
A IR C ONDITIONING (HVAC),
AND E LECTRICAL W ORK
backfl ow preventer duplex houses electrical estimating
heat exchangers HVAC
plumbing
Introduction
Plumbing, heating, ventilating, air conditioning (HVAC), and electrical work are in- variably performed by subcontractors on residential projects, but these trades rep- resent a signifi cant part of a project, usually accounting for more that 30 percent of the total project cost. It is, therefore, useful for the builder’s estimator to be able to check trade quotes to ensure that they cover the full scope of work for that trade.
Certainly estimates of large and/or complicated projects call for the expertise of spe- cialists in these trades. Like any other estimators, those working on plumbing, HVAC, and electrical work need a thorough knowledge of how the work is done in that trade before they can assemble accurate quotes for the work. To be accurate, the prices for these quotes will have to be estimated using the same meticulous method used by build- ing estimators with their work. That is, fi rst prepare an accurate takeoff of the work items, then, by means of unit prices, calculate the anticipated cost of these items of work.
The ability to compile a takeoff of plumbing, HVAC, and electrical work can also be a useful skill for the builder’s estimator who sometimes needs to put together a quick price for these trades on a small project. Indeed, some builders like to de- velop their own cost estimate for each trade’s scope of work to ensure that the quotes received are reasonable; takeoff skills are defi nitely an asset if this analysis is to be done properly. Below we have identifi ed the main items of work and how they are measured in a takeoff for each of these trades.
Plumbing Work Generally
On small residential projects, such as single houses and duplex houses, it is unusual to see much information about the plumbing system on the project plans other than, perhaps, the location of the main plumbing vent and basement fl oor drains. Lacking details from the plans, the estimator often has to draw sketches to be able to assess the plumbing layout for a house. These sketches can then help the estimator evaluate measurements such as the length of pipes for water supply and sewers on the project.
Measuring Notes—Plumbing Work Water Distribution
1. Enumerate connections of water lines to the main.
2. Describe and measure hot water and cold water pipes in linear feet.
3. Describe and enumerate fi ttings and valves.
4. Describe and enumerate hangers and supports for pipes.
Sanitary Sewer Pipes and Fittings
5. Describe and measure pipes in linear feet to 5 feet from the building.
6. Describe and enumerate backfl ow preventers, cleanouts, fl oor drains, roof drains, valves, and fi ttings.
7. Describe and enumerate hangers and supports for piping.
Fixtures and Equipment
8. Describe and enumerate fi xtures and equipment, including:
a. Water meters
b. Gas meters
c. Water pressure reducing valves
d. Water heaters
e. Pumps
f. Lavatory basins
g. Water closets
h. Bidets
i. Sinks
j. Laundry tubs
k. Bath tubs
9. Describe and enumerate separately equipment supplied by the builder and installed by the plumber, including:
a. Refrigerators
b. Garbage disposal equipment
c. Dishwashers
Gas Lines
10. Describe and measure in linear feet gas line piping from the gas meter to all terminal points.
11. Describe and enumerate fi ttings and valves.
12. Describe and enumerate hangers and supports.
Miscellaneous Plumbing Items
13. Describe and enumerate permits for the work.
14. Describe pipe insulation and measure in linear feet.
15. Describe and enumerate pressure testing of lines.
16. Describe and enumerate cutting, drilling, and patching required for this work.
17. Measure cleanup resulting from this work as an item.
HVAC Work Generally
Often the only HVAC information provided on plans of small residential projects is only the location of the furnace. So, before the estimator is able to takeoff this work, she/he needs to determine the position of heating ducts, air outlets and inlets, and thermostats. An outline of the location of ductwork sketched on the fl oorplans is useful for this purpose.
Measuring Notes—HVAC Work Ductwork and Venting
1. Describe ductwork, stating the size and measure in linear feet.
2. Describe range, cooktop, laundry, and bath venting stating the size and mea- sure in linear feet.
3. Describe transitions and measure in linear feet stating the size at each end.
4. Describe elbows stating the size and enumerate.
5. Describe “Y” fi ttings stating the size and enumerate.
6. Describe fi ttings, hangers, and sleeve frames stating the size and enumerate these items.
Mechanical Equipment
7. Describe and enumerate mechanical equipment items, including:
a. Air handling units
b. Furnaces
c. Heat exchangers
d. Heat pumps
e. Refrigeration compressors
f. Refrigerant condensing units
g. Water coolers
h. Humidity control equipment
i. Floor-heating and snow-melting equipment
HVAC Controls
8. Describe control wiring and measure in linear feet.
9. Describe low-voltage wiring and measure in linear feet.
10. Describe and enumerate electric and electronic controls.
11. Measure both testing and balancing as items.
Miscellaneous HVAC Items
12. Describe and enumerate permits for the work.
13. Describe duct insulation and measure in square feet.
14. Describe and enumerate fi re stops and fl ashings.
15. Describe and enumerate cutting, drilling, and patching required for this work.
16. Measure cleanup resulting from this work as an item.
Electrical Work Generally
Residential plans generally show the location of light fi xtures, switches, and at least some of the wiring. The location of duplex receptacles is also noted on the drawings, however, the layout of power wiring is seldom shown. Sketches, especially with colored pens, can here again be a great help to the estimator measuring the work of this trade.
Measuring Notes—Electrical Work Wiring
1. Describe wire, cable, and conduits and measure in linear feet.
2. Describe cable tray and bus duct systems and measure in linear feet.
3. Describe and enumerate hangers, sleeves, and supports.
Electrical Equipment, Fittings, and Fixtures
4. Describe and enumerate electrical equipment, fi ttings, and fi xtures, including:
a. Fire alarm systems
b. Security systems
c. Communication systems
d. Medium-voltage switching equipment e. Low-voltage switching equipment f. Electrical panels and sub-panels
g. Junction boxes
h. Outlet receptacles
i. Switches
j. Light fi xtures
k. Door bells
l. Fans
m. Range hoods
n. Smoke detectors
5. Describe and enumerate installing appliances, including:
a. Cooktops
b. Microwave ovens
c. Built-in ovens
d. Range hoods
Miscellaneous Electrical Items
6. Describe and enumerate permits for the work.
7. Describe and enumerate fi re stops and fl ashings.
8. Describe and enumerate cutting, drilling, and patching required for electrical work.
9. Measure testing and hot checking entire system as an item.
10. Measure cleanup required as a result of this work as an item.
Pricing the Work
Materials can be priced in the usual manner using supplier quotes for the items involved. However, because the builder does not perform this work with their own forces, there will be no in-house historic cost information available to use to estimate the cost of labor and equipment for this work. The builder’s estimator will, therefore, have to rely on productivities and prices obtained from subtrades if they are willing to share this information. Otherwise, the estimator will have to resort to publica- tions such as RSMeans Plumbing Cost Data,1 RSMeans Electrical Cost Data, and so on for prices.
Estimating Shortcuts
Instead of compiling a full takeoff on the smaller projects, many plumbing, HVAC, and electrical estimators use shortcuts to compute their prices for this work. Building estimators who need quick budget prices for these trades can also make use of these time-saving methods.
For the plumbing, HVAC, and electrical trades, a price per square foot of gross fl oor area could be used to provide at least a rough estimate of the cost of that trade.
Often, though, especially for bid estimates, something that gives a more accurate price is called for.
Cost Per Fixture Plumbing Estimate
A quick estimate for plumbing work can be obtained by means of a unit price for each plumbing fi xture on the project. The cost of all necessary piping and any other required work is allowed for in each of these unit prices. So, enumerating the fol- lowing fi xtures and multiplying by the applicable price for each fi xture will give the estimated price for the complete plumbing work:
a. Floor drains b. Water heaters c. Lavatory basins d. Water closets
1. R. S. Means Company Inc., Kingston, MA
e. Sinks
f. Laundry tubs g. Bath tubs
Additional prices may be required for installing appliances, special fi xtures, and any out-of-the-ordinary plumbing work requirements.
Plumbing Example
Suppose you are considering adding a three-fi xture bathroom to a home design and you would like to know roughly what the plumbing price would be. The plumber can quickly estimate the price based on the number and type of fi ttings involved and all-inclusive price for these fi ttings.
EXAMPLE 7.1
Estimate of plumbing price for a 3-fi xture bathroom:
1 bathtub 72" 3 36" $2,500
1 water closet $1,485
1 lavatory basin 19" 3 16" $1,160 $5,145 Extra for pipe and fi ttings 30% $1,544 Total $6,689
Quick Estimates of HVAC Work
The cost of HVAC work can be estimated quite quickly by using a combination of prices per unit area and unit prices for items of equipment. The overall cost of ductwork includ- ing ducts and all fi ttings is proportional to the fl oor area of the house. A fairly accurate price per square foot, therefore, can be obtained from the analysis of projects that have been completed in the past. Thus, to estimate the total cost of ductwork for a house, multiply the unit price from a past project by the gross fl oor area of the new house.
The estimator can also compile all-inclusive equipment item prices for each item of equipment used in the HVAC system. An item price would include the cost of pur- chasing the item of equipment, installing the item, and any further costs necessary to complete its installation. So, to compile a full HVAC estimate, determine how many of the following equipment items are required, and multiply by the appropriate item price for each:
a. Furnaces b. Heat exchangers
c. Refrigeration compressors d. Refrigerant condensing units e. Water coolers
f. Humidifi ers
g. Kitchen and bathroom vents
HVAC Example
To quickly calculate the heating and ventilating price for a house, we can use a price per unit area and add the cost of non-standard fi xtures. So, if the proposed house is
2,200 square feet of fl oor area and a special humidifi er and exhaust fan are required, this would be the estimate:
EXAMPLE 7.2
Quick heating and ventilating price:
Basic HVAC 2,200 SF at $5.50/SF $12,100
Humidifi er $2,500
Exhaust fan $350
$14,950
Quick Estimates of Electrical Work
The cost of electrical work can also be estimated quickly by means of a combination of prices per unit area and prices for items of equipment and fi xtures:
1. To estimate the full price of wiring for lighting, multiply gross fl oor area by the inclusive unit price per square foot.
2. To estimate the full price of power wiring and fi ttings, multiply the number of power outlets by inclusive price per outlet.
3. To estimate the price of equipment and fi xtures, multiply the number of each item by unit price for that item, including:
a. Electrical panels
b. Subpanels
c. Light fi xtures
d. Doorbells
e. Fans
f. Range hoods
g. Smoke detectors
h. Cooktops
i. Microwave ovens
j. Built-in ovens
k. Range hoods
Electrical Example
To quickly calculate the electrical price for a house, we can use a price per unit area and add the cost of non-standard fi xtures. So, if the proposed house is 2,200 square feet of fl oor area and a security system with motion detectors is required, this would be the estimate:
EXAMPLE 7.3 Quick electrical price:
Basic electrical 2,200 SF at $8.50/SF $18,700
Security system $3,500
$22,200
SUMMARY
■ It is customary to perform plumbing, HVAC, and electrical work by subcon- tractors on residential projects.
■ Because plumbing, HVAC, and electrical work accounts for so much of the total price of a project, it is useful for the building estimator to be able to check the subtrade quotes for these trades.
■ Because building estimators sometimes estimate these trades on small proj- ects, the ability to compile takeoff of this work can be useful to them.
■ Very little information about plumbing, HVAC, and electrical work is found on drawings for small residential projects, so estimators often need to prepare sketches of this work.
■ Plumbing pipes and gas lines are measured in linear feet in a takeoff.
■ Plumbing fi ttings and equipment are enumerated.
■ HVAC ductwork is measured in linear feet for each size of duct.
■ HVAC fi ttings and items of equipment are enumerated.
■ Electrical wiring, cables, and conduit are measured in linear feet.
■ Electrical equipment, fi ttings, and fi xtures are enumerated.
■ Installation of appliances is enumerated.
■ The builder’s estimator will generally have to rely on publications such as Means Plumbing Cost Data in order to price plumbing, HVAC, and electrical work.
■ Costs of plumbing, HVAC, and electrical work can be quickly estimated using the price per unit area estimating method.
■ A quick estimate of plumbing work can be assembled using the cost per plumbing fi xture method.
■ A combination of price per unit area and unit prices per item of equipment can be used to generate a quick HVAC cost estimate.
■ A combination of price per unit area and unit prices per item of equipment can also be used to generate a quick electrical work estimate.
RECOMMENDED RESOURCES
Information Web Page Address
■ R.S. Means publishes specialized estimating http://www.rsmeans.com/
texts for plumbing, HVAC, and electrical work.
■ Information on the latest estimating software can be obtained with keywords: Plumbing, HVAC, and Electrical Estimating on your web search engine.
REVIEW QUESTIONS
1. What portion of the total cost of a residential project does plumbing, HVAC, and electrical work together account for?
2. Why it is useful for a building estimator to be able to prepare a takeoff of HVAC work?
3. How much information about the plumbing system is usually provided on hous- ing plans?
4. To what distance outside the house are sanitary sewer lines measured in a plumb- ing takeoff?
5. How is piping insulation measured?
6. Describe how you would measure bathroom venting in an HVAC takeoff.
7. How is testing and balancing of an HVAC system measured?
8. If a cooktop is required for a kitchen, its cost is included in the builder’s work, so why is it measured again as part of the electrical scope of work?
9. Wiring or conduit passing through walls sometimes requires fi re stops or fl ash- ings. How are these items measured?
10. Describe a quick method for estimating the cost of HVAC work.
PRACTICE PROBLEMS
1. Calculate a quick plumbing price for a four-fi xture bathroom based on the fol- lowing data: Fixtures: 1 bathtub at $2,450; 1 shower unit at $1,000; 1 WC at
$1,400; and 1 Lavatory basin at $850. Also include an additional 30 percent for pipe and fi ttings.
2. Calculate quick plumbing, HVAC, and electrical prices for a 3,100-square-foot home based on the following data: Plumbing is expected to be $6.50 per square foot; HVAC $4.25 per square foot; and electrical work $6.75 per square foot.
