Foundation Inspectionimage used with permission from (and thanks to) http://www.DawsonFoundationRepair.com
What is a foundation inspection?
It is universally accepted that a solid foundation is needed to support the dwelling, the person, the institution, the whatever. In the case of a home foundation inspection we look at many things.
Home foundation inspection – Inside hints
A floor that’s not level is one tip of a possible foundation problem.
Doors that begin to jam or fail to latch; cracks appear in walls, especially over doorways or windows or where walls meet ceilings; cracks open in vinyl or ceramic tile over a concrete floor or windows that fail to budge or to close completely could also hint at foundation problems
Home foundation inspection – Slab foundation
If you have a slab foundation, I assess visible cracks and make a determination based on size, direction of movement, and location , or if a structural engineer is needed to determine whether these signs point to normal settling or to structural damage.
Home foundation inspection – Problem found, what now?
If it’s a structural problem, your foundation is settling unevenly and has the potential to skew or pull apart the framing unless you take action. Home inspectors are generalist and if problems are discovered that may be serious, a specialist will be needed to fully evaluate and adviseher.
Home foundation inspection – Exterior hints
Check to see if your foundation is straight by sighting down the length of your foundation wall from each corner. You should see a straight line. A bulge or divot in either a block foundation or a poured concrete wall could signal that the foundation has shifted. You can also do this on the interior of the foundation wall.
Check for leaning walls with a level. If the top of the foundation sticks out beyond the walls in one area, the foundation wall may have tipped. Any signs of shifting or bowing means that the soil may be expanding and contracting, putting pressure on foundation walls, and remedial steps are necessary.
Home foundation inspection – Checking crawl spaces
In the basement or crawl space, I look for foundation problems that may include a system of posts and concrete supports, or piers. Posts should stand straight and be firmly planted completly underneath the beams they support. Bottoms of posts should rest firmly on concrete. Post tops should be secured to the supported member.
Standing water, wetness or signs of water intrusion are a red flag for inspectors and will be noted for repair. Moisture is a major contributor to house damage as are wood destroying insects. These will be investigated in a WDIR (wood destroying insect report) performed during a home termite inspection by a qualified pest inspector.
Wood posts, joist, band boards, and sill plates are probed with a screwdriver or awl to determine their composition integrity.
Home foundation inspection – Reading cracks
Concrete and block foundations usually have at least a few cracks. The skill is recognizing which are insignificant and which are serious.
As concrete cures, it shrinks slightly. Where the concrete can’t shrink evenly, it tends to crack. Cracks where there is an L-shape section, such as where a foundation stairsteps down to follow a hillside, are probably shrinkage cracks, especially if they meander and taper down to a hairline. These aren’t a structural issue, though you might need to plug them to keep the basement or crawl space dry. Hairline cracks in the mortar between concrete blocks are also rarely worth worrying about.
If you find small cracks (less than 1/16-inch wide), paint over them with a concrete waterproofing paint. Then check periodically to see whether the paint has cracked, which means the gap is opening up under pressure.
Stairstep cracks in masonry joints are a bigger concern, especially if the wall is bulging or the crack is wider than ¼ inch. A plugged gutter or other moisture problem outside may be exerting pressure on that part of the wall.
Horizontal cracks are most serious, and indicate that water-saturated soil outside froze and expanded, pushing in and breaking the foundation. Perhaps gutters are backed up and heat was off for an extended period during especially cold weather.
Horizontal cracks also occur because of problems with underlying soil. If you have soil that expands when damp and shrinks when dry, you face the same range of solutions as if you had a slab foundation and should hire a structural engineer as needed.
If I had to identify which system in a home inspection is the most critical I would say the foundation inspection. Second most important after the foundation inspection would be the roof inspection.