We have a crack in our foundation wall. Do we need to be concerned about it structurally? And could termites enter through it?
Put it this way: A crack doesn't have to create structural troubles for it to be a problem. Cracks are ugly, suspicious things that aren't easy to fix, and even one that's no more than a hairline could grow and create all kinds of difficulties.
I would say any crack wider than 1/16 inch is a problem, especially if it admits water or increases in width or length, or if its faces grind against each other with changes in temperature and humidity. All of these indicate foundation movementand that's not good.
As for termites, those pests can slip through a crack that's 1/64 inch wide. If you live in an area where termites are common, have your home inspected by a licensed termite-control contractor.
The good news is that in most cases only large cracks indicate structural trouble. You'll need to contact a structural engineer or foundation repair company if the crack wraps around a corner, reaches from the basement floor to the top of the foundation wall, or runs horizontally and the wall below it leans into the basement. All of these problems indicate that the soil supporting the foundation is moving (horizontally or vertically) and taking the foundation with it.
It's tough to fix a crack. It's one thing to simply fill it with epoxy and hope that it holds. It's a much larger matter to evaluate the foundation inside and out and determine what's causing the crack, undertake those repairs, and then seal the crack shut for good. That kind of repair is expensive and often involves reducing the hydraulic forces acting on the foundation by installing drainage pipes, gravel, filter fabric, a sump pit, and a pump. In the worst cases, the foundation may need additional support from piers driven next to it. It takes an experienced foundation repair company to do that work.
If you're going to attempt a DIY repair, do your homework. A number of sites offer small-scale versions of epoxy injection kits used by contractors, and you can still buy tried-and-true cement-based products such as those made by Thoro (thoroproducts.com).
Roy Berendsohn has worked for more than 25 years at Popular Mechanics, where he has written on carpentry, masonry, painting, plumbing, electrical, woodworking, blacksmithing, welding, lawn care, chainsaw use, and outdoor power equipment. When he’s not working on his own house, he volunteers with Sovereign Grace Church doing home repair for families in rural, suburban and urban locations throughout central and southern New Jersey.
