Foundation Inspection Procedures
As a home inspector you’re often the first to identify the signs of foundation failure. It’s important to conduct a foundation inspection to identify and document structural problems which can present safety issues.
When conducting an inspection take into consideration the building’s movement and settlement, soil and the extent of foundation cracking or other problems.
As the home inspector you’re accountable for the foundation inspection of the visible portions. In some situations the foundation may appear sound however if historical information is reviewed it may provide you with additional information that leads to a potential structural problem.
When conducting a foundation inspection it’s important to look for the various foundation failure signs which could indicate the structure is unstable. There are some foundation failure problems that can lead to sudden collapse of the structure: bowed walls, bulging walls or extensive foundation cracks. If you have additional concerns about the structure’s stability or safety, contact a foundation repair expert.
When evaluating a foundation crack, you’ll need to look at the size, location and type of crack. The pattern, angles, length, width and variance will all give you a clue to the type of crack and if it’s an indication of foundation failure.
This is an informational chart which can provide you with insight into the type of crack. However it’s important to take into account the building’s location, history, interior condition, and soil to get a complete picture of the type of crack and potential foundation problems.
|Uniform||Doesn’t extend to the bottom of the foundation wall||Concrete||Shrinkage||Shrinkage cracks occur when the concrete dries. They don’t often present a structural problem.|
|V-shaped, wider at the top of the crack and narrows at the bottom||Doesn’t extend to the bottom of the foundation wall||Concrete||Shrinkage||Shrinkage cracks occur when the concrete dries. They don’t often present a structural problem.|
|V-shaped, wider at the top of the crack and narrows, extends past the bottom of foundation wall.||Extends past the bottom of the foundation wall, potentially into the footing||Concrete||Shrinkage||This type of shrinkage crack can present a structural problem.|
|Hairline (less than 1/16” wide), non-uniform, discontinuous cracks||Random cracks located throughout the wall or floor. They do not extend past the bottom of the foundation wall.||Concrete||Concrete Shrinkage||These types of cracks can indicate that the concrete wasn’t mixed properly, rapid curing or steel reinforcement wasn’t placed properly. This type of shrinkage cracks don’t typically present a structural problem.|
|Uniform, narrow||In the center of the concrete block wall||Concrete Block||Shrinkage||Block foundation walls rarely expand due to moisture and temperature variations. These types of cracks can be attributed to shrinkage and don’t necessarily present a structural problem. Continued monitoring is advised.|
|Broken bond courses, bowing||Any location||Brick||Settlement, movement, or thermal expansion||Can result in serious problems and collapse|
|Stair step||Any location||Brick or concrete block||Thermal or expansion||Can present foundation failure if the bond courses are broken or bricks are rotating out.|
|Wider at the bottom of the crack||Wall, not near the bottom of the foundation wall||Concrete Block wall||Settlement||Depending on the extent of the crack, it could create structural problems.|
|Wider at the bottom of the crack, broken bond courses||Wall or near the bottom of the foundation wall||Brick||Settlement||Serious. Could pose a collapse risk.|
|Wider at the top than bottom||Corner to adjacent opening||Concrete||Settlement, expansive soil or evaporation||Could indicate structural problems|
|Vertical, window sill’s bowed up||Under a ground-level window to the ground||Brick, Concrete||Foundation heave or expansive soil||Could indicate structural problems|
|Vertical cracks or diagonal||Center of header or the corners of the building||Brick, Concrete||Loading failure or point-load failure||Foundation failure|
|Horizontal cracks||High on foundation wall, in the upper third||Concrete Block Foundation or Stone Walls||Frost damage, drainage problems, or vehicle loading (where the drive way is located)||Frost can damage the upper third of the foundation, near the eaves. Monitoring is required to ensure that this crack doesn’t continue to grow and present a structural problem.|
|Horizontal cracks||Mid height in the wall||Concrete Block Foundation or Stone Walls||Vehicle loading, backfill damage or drainage problems||The width, depth and location of the crack can indicate the severity of the problem. If the wall is bowing then collapse can occur.|
|Horizontal crack||Low on the foundation wall, near the bottom||Concrete Block Foundation or Stone Walls||Expansive soils or earth loading||Can be a sign of early foundation failure. If the crack is pushed inwards that the structure will require additional support.|
|Continuous, may be wider at the top than bottom, or horizontal||Floor or wall||Concrete||Foundation footing settlement||The structure may require additional support to prevent foundation failure and stabilize.|
Foundation Crack Severity
It’s important that you don’t make a conclusion on the severity of the crack just based on the size and location. There are other site factors to take into consideration like the building’s history, soil, materials used for construction, and external factors
Minor foundation cracks:
Hairline – less than 1/16-inch – and are horizontal. Concrete slab cracks that don’t extend into the foundation and are hairline – 1/8-inch. Hairline stair step or vertical cracks – less than 1/8-inch – that don’t extend into the foundation footing.
Moderate foundation damage that requires
monitoring or repair:
Old cracks with no sign of continuing movement. Mortar cracks that are a result of damage caused by backfill being installed too early when the mortar was still green. A horizontal bulge that is less than 1.5-inch and there’s no other sign of foundation cracking or damage. However repairing this problem early on will save the homeowner money in later repairs.
Severe foundation damage that require a
professional foundation inspection:
Sudden appearance of foundation cracking, especially in areas prone to sink holes.
Bowed walls or bulges greater than or equal to 1.5-inch.
Walls leaning or lateral dislocation greater than 1/4-inch.
When there are signs of recent or recurrent movement and settlement.
Cracks are wider than 3/8-inch.
Other Foundation Failure Signs
When conducting a foundation inspection you’ll also need to look for other signs of failure. If you come across any of these other problems in addition to foundation cracking than the structure may require underpinning or additional support to stabilize the foundation and prevent additional damage.
Dislocated wiring, plumbing or lines:
In some cases, serious settlement or movement can result in lines dislocating or disconnecting from a joint. If this occurs, then the structure is experiencing foundation failure in addition to other safety problems.
Broken structural connections:
If the structure has shifted off of the foundation or slab, or there are broken sill bolts than a foundation repair expert needs to be consulted. They will help you find the extent of the damage and determine the cause.
When inspecting horizontal cracks and stair step cracks also look for a bowing or bulging of the wall. It may vary from a subtle bow to an extreme bulge. The source of these problems could be due to hydrostatic pressure, expansive soils, or drainage issues. This type of problem is always indicative of foundation failure.
Any leaning can create a problem but if the lean is more than 1/4-inch then structural repair is required.
If the extent of the foundation cracking allows water into the crawl space or basement, than additional action may need to be taken to prevent the crack from growing.
To be used properly, this information needs to be combined with on-site observations at the structure which requires a foundation inspection. If you’re concerned about the building’s safety, stability or foundation condition please consult with a foundation inspection expert.