Our Guide to Repairing Cracks in Your Home’s Foundation
However, many small cracks, or a substantial one, can mean a big entry point for groundwater which can lead to major water damage in the springtime.
Keeping a lookout for problem cracks and getting them fixed early can save you much time and money in damage repairs. Find out how to identify and read cracks, and what your repair options are.
Why Foundations Crack
Foundations may develop cracks for a number of reasons including shrinkage during the concrete curing process, a lack of appropriate control joints in the foundation walls, or when a house settles or the ground beneath it shifts (this usually results in the largest cracks).
Cracks develop in every poured concrete structure, regardless of the size, type, and whether it’s reinforced or not – so do not fret if you see some. If your foundation has a crack larger than 1/4 inch wide, have it examined by a structural engineer or foundation specialist.
An expert will be able to determine whether it points to structural damage and requires major repairs. An inspection and evaluation may cost anywhere between $500 – 700. When it comes to a damaged foundation, you certainly don’t want to skimp on an expert opinion.
How to Identify and “Read” Cracks
Look for these signs of foundation cracks, or warning signs that dramatic changes are taking place as a result:
- Cracks that appear in basement walls, especially over doorways, windows, or where walls meet ceiling. Concrete cracks often occur at the natural stress points where the uniformity of a poured concrete wall or floor has been interrupted by placement of a window or inside corners (in floors)
- Cracks open in vinyl or ceramic tiles over a concrete floor
- Water seepage or basement flooding during moderate to heavy rain
- Outside of the home, chipping or very brittle concrete along the bottom sides of the house
- Hairline, spider-like cracks in the spaces between, or through, concrete blocks are rarely worth worrying about (see below how to repair these yourself)
- Cracks at an L-shape section (where a foundation steps down to follow a slope in the ground), are likely shrinkage cracks, especially if they “wander” and taper off to a hairline. These likely won’t cause a structural issue though you might need to seal them to keep the basement dry
- Cracks that follow the spaces between bricks or concrete blocks point to a bigger concern, especially if the wall juts out at uneven levels. A moisture problem outside is probably exerting pressure on that part of the wall
- Generally, horizontal cracks in walls are most serious. Horizontal cracking higher up on the wall is likely from the freeze-thaw cycle. When water from downspouts saturate the area, it freezes and puts pressure on the basement wall
Crack Repair Options
If you find small cracks (less than 1/4 wide), you can paint over them with a concrete waterproofing paint (about $25 per gallon and available in hardware stores). Check periodically to see whether the paint has cracked, which means the crack is opening up under pressure.
Or, use a high-quality polyurethane caulk to fill in the joint (be sure to avoid these common caulking mistakes). A polyurethane caulk will remain pliable to allow for ongoing expansion and contraction. Lightly spray the area with water twice per day for a week to help it cure and prevent cracking.
If you do find a problem crack, though, be sure to recruit the right expert to do the job – foundation crack repair requires knowledgeable analysis of the cause of the crack. Call several foundation specialist and have a technician come over to provide an opinion and quote.