4 tips for dealing with foundation repairs

July 28, 2015

Foundation inspections and repairs are important in preserving the health and resell value of your home. Here are four tips in foundation repair.

4 tips for dealing with foundation repairs

1. Caulking small cracks

  • Check the joints between the foundation of your house and your patios and porches. If you find a gap, brush the area clean.
  • Then use a caulk gun with a tube of urethane or silicone-modified acrylic caulk rated for concrete to fill the gap. Smooth it to blend with the surrounding surfaces.
  • Caulk gaps between the foundation and siding the same way. Also caulk cracks in the foundation itself if they are no more than three millimetres (1/8 inch) wide.
  • When you are caulking cracks and gaps between the foundation and siding, use a mirror to see under the edge of the siding so that you don't have to hunch over. You may have to prop the mirror on a block of wood to position it at the best angle.

2. Examine the crawl space

  • It's easy to overlook what's going on in a crawl space, but if you do, you may pay for it later on. Trapped moisture can damage your house's wooden understructure.
  • If your house rests on perimeter foundation walls with a dirt-floor crawl space beneath, keep the crawl space dry with a vapour barrier of six millimetre (1/4 inch) polyethylene film.
  • To install, dig a five centimetre (two inch) deep ditch around the interior perimeter of the crawl space.
  • Lay sheets of polyethylene film over the ground, overlapping them at least 0.6 metres (two feet) and extending their outer edges into the ditch.
  • Return the excavated soil to the ditch to anchor the plastic. If you can't dig a trench, weight down the plastic with gravel or bricks.
  • Slithering around in a tight crawl space is much easier if you get a light with an elastic band that straps around your head and keeps your hands free. They're available at camping and mountaineering supply stores. They're great for any job that requires a flashlight.

3. Repairing larger cracks

  • Patch a crack in your foundation that's more than three millimetres (1/8 inch) wide. If it extends below ground level, dig a small trench to reach it, saving the dirt to refill the trench.
  • Wearing a dust mask, goggles, and work gloves, scrape off any dirt around the crack; then clean the area with a stiff-bristle brush and mists of water from a spray bottle. Let the wall dry. Don't hose; it'll take too long to dry.
  • Chip away any crumbling material with a cold chisel and hammer. Then chisel the crack to undercut the edges, making the crack wider inside than on the outer surface. This will lock in the patching material when it hardens.
  • Prepare a small batch of concrete patching compund, mixing in enough water to make it pliable but not runny. Use a pointed trowel to force the mixture into the crack, slightly overfilling it; then smooth the surface with the trowel to blend the compound with the surrounding surface.
  • After the repair has hardened, seal the surface with masonry waterproof coating. Let it dry, then paint to match the surrounding surface.

4. Sealing

  • To keep water from leaking through a stone foundation onto the dirt floor of a crawl space, seal the joints between the stones both outside and in. Wear work gloves and goggles.
  • On the outside, rake out crumbling mortar using a hammer and chisel and clean with a stiff brush. Dampen the joints and fill the voids with a packaged mortar mix, as you would when repointing a brick veneer wall.
  • Inside the crawl space, repeat the process. Then seal the interior surface with masonry waterproof coating. If you don't mind losing the look of the natural stone, you can also waterproof the exterior and paint over the waterproof coating.
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