The home inspector starts the inspection of the foundation from the outsideof the house, watching for signs of footing and
foundation failure on the exterior. The inspector looks for
settlement or movementof the house and their effect on the
rest of the structure. While some signs note obvious problems, other signs may only indicate that the inspector must continue to investigate to find the cause of the exterior sign. The inspector focuses on the following:
• The ridge line of the roof • Racking or leaning of the house
• The chimney pulling away from the house • Twisted siding
• Movement of foundation wall and cracks • Corners of the building settling
• Cracks in exterior walls • Displacement of windows
The inspector also inspects the foundation from inside, from
the basement or crawl space, paying attention to: • Cracks in foundation walls
• Bowing or leaning of foundation walls • Window displacement
• Deterioration of materials in the walls, piers, and supports • Evidence of water penetration
Cracks
Wall cracks appear as the result of overloading or because of settlement or heaving. The location and pattern of the cracks can be a clue to what is going on with a foundation.
Vertical cracksare most often caused as a result of
settlement of the structure, soil compacting, or soil washing away under the footings. It occurs when there is an upwards overload force next to a downwards overload force. They can also occur after remodeling, when
new dead loads are added to the structure, or by adding very heavy live loads.
Guide Note
Pages 22 to 42 present the procedures for foundation inspections.
Worksheet Answers(page 21)
1. C 2. A 3. B 4. D 5. A 6. A 7. A 8. B
9. Because defects can be present in a crawl space or attic, the home inspector must let the customer know if the inspector was unable to gain access to the crawl space or attic to find those defects. The inspection guidelines stress this point because of the liability. The customer should understand that defects cannot be reported if access is impossible or limited.
Vertical cracks that extend down to the footing may be serious and should be investigated carefully. This could be caused by uneven settlement of the building and could indicate the wall is separating — one part settling more on one side of the crack than the other. The crack extending to the footing could also indicate a failure of materials such as deteriorating block, decayed
mortar, or weak concrete.
This diagram shows the results of settling due to soil weakness at one side of the house. Note that cracking on both the exterior as well
as on the foundation wall are indications of the settlement. In this case, one part of the house is pulling away from the other .
Angled cracks appear when the
upload and download offset each other. They can appear when there is a major difference in the soil under the house from one location to another, heaving of the soil, and resulting footing failure. This type of crack points down to the location of the upload. In block construction, the angled crack may appear along the block joints in an angled direction.
This is called a step crackand is shown here.
Angled cracks can appear in pairs, where a load in one direction is offset by a pair of loads from the other direction.
Greater Load at Bottom with Wider Angle
Greater Load at Top with Steep Angle
Equal Loads Top and Bottom with Equal Angles
Settlement
Greater Load at Bottom with Wider Angle
Greater Load at Top with Steep Angle
Equal Loads Top and Bottom with Equal Angles
Settlement
Greater Load at Bottom with Wider Angle
Greater Load at Top with Steep Angle
Equal Loads Top and Bottom with Equal Angles Settlement FOUNDATION CRACKS • Vertical cracks • Angled cracks • Horizontal cracks • Shrinkage cracks
The house diagram shows the result of settlement, where the stress is born at one corner of the house. Here, the angled step crack is likely to have a companion crack on the adjacent wall at that corner, indicating that corner is breaking away from the rest of the house entirely and sinking. When a crack is at a single
corner of the house, it can indicate a broken footing because of the condition of the soil underneath, expansive clay soils, or even the uplift from heavy tree roots in that location. Ahorizontal crackon the foundation wall can be an
indication of pressure being applied from outside. The cause can be soil pressure
against the wall, improper backfilling, and surface problems such as poor down- spouts that increase the amount of water pushing against the wall. The wall will bow inward and crack horizontally.
If the wall is actually displaced— when the surface of the wall
is out of alignment — and the crack is wider on the inside face of the wall, serious problems can result. Concrete block and masonry walls will usually show the horizontal crack along the mortar joint.
There are other causes for horizontal cracks in foundation walls. There could be a vertical overload on the wall. Or the crack could be caused by settlement, where the wall has dropped when the soil underneath settled. In this case, the home
inspector would probably not see any lateral displacement. Cracks may also be caused by heavy equipment during backfilling.
Settlement
Settlement
V-CRACKS
When a crack increases in width along its path, this is called a V-crack. A vertical V-crack, wider at the top, indicates the wall is settling at the ends of the wall more than in the middle. A horizontal V-crack, as seen in the side diagram of the wall on this page, indicates the wall is moving out from the middle more than from the top and bottom.
The home inspector may see pilasters — masonry or block
columns against the interior foundation wall — built to support the wall and help absorb the lateral load. Pilasters may be part of the original construction or erected later as a corrective measure.
Shrinkage crackscan appear in foundation walls as part of
the curing process. In the concrete block wall, you may see symmetrical step cracks that indicate block shrinkage. If the cracks appear around each block, this could be an indication of block shrinkage due to too much moisture in the blocks when they were set. It could also be the result of mortar that was placed in cold weather that later froze and expanded before curing. The home inspector may see a vertical shrinkage crack in the middle of a concrete block wall. The crack can be wider at the top indicating shrinkage during cure, where the bottom of the wall is held firm by the footings.
In the poured concrete foundation wall, shrinkage usually occurs naturally in the first few months. Some poured concrete walls are designed to have control areas, like seams, where cracking can be localized. If these areas are not provided, cracking is likely to be random over the surface of the wall.