Renovation & Design

ASK THE INSPECTOR: Stop water leakage in foundation bolt holes

QUESTION: We have a 40-year-old bungalow. Over the past four years, one wall in the basement has been giving us a problem. If it rains, water runs out of the iron-rusted bolts, which I assume are the rods that attached the cement back steps to the house. It's only these four bolted areas that leak and we have tried countless remedies to plug these holes, but sooner or later they leak again. The water streams down the wall and heads to the sewer.

Who can I call to fix this and how huge and expensive will this project be? Thanks, Barb Potkonjak.

ANSWER: Any openings in a concrete foundation wall can allow moisture to enter, especially if they are below grade. Sealing the holes may be possible either internally or externally, but will depend largely on access. This time of year is ideal for this discussion, as many homeowners will see minor seepage as the snow melts and the ground thaws after the long winter.

The initial thing to determine is where these bolts, and the corresponding holes around them, are located relative to grade. You are probably correct these are used to secure your steps to the foundation, which are commonly used on older precast concrete steps and landings.

Often, these bolts are installed above grade below a doorway, which should cause little concern unless the steps have moved. Using a basement window, dryer vent, fresh-air intake duct or gas line as a reference point should help you determine if they are above or below the soil outside the foundation. If they are above grade, repairs should be easier than if they are lower.

It's quite likely water from heavy rains will be able to run down the walls of your home behind your steps and leak through the small holes in the foundation where the troublesome bolts are located, even if they are well above grade. This is much more likely if the steps have sunk or pulled away from the foundation even a small amount. Quite often, this occurs and leaves a fairly large gap between the precast steps and the foundation wall.

If this is what you find, filling or covering that gap may be all you need to stop the leakage. If the gap is small, filling it with an exterior-grade caulking at the top and down the sides of the steps should prevent rainwater from getting to the holes. If the gap is larger, filling it with flexible foam rods before caulking may be required. Otherwise, installation of a metal flashing that is sealed to the siding and fully covers the top of the gap may divert water away from the opening.

If you find the bolt holes are below grade, more expensive work may be required. Again, the condition of the steps should be checked initially. If they do not appear to have moved and are in the original location of installation, interior repairs may be possible. If the steps have sunken, pulled away from the home or are otherwise damaged, removal may be your next step.

Detaching the steps from the foundation by cutting or removing the bolts will allow access to the offending holes, then it should be quite simple to repair these openings from the outside. These could be filled with typical concrete patching compound. Once cured, waterproofing compound or small pieces of foundation membrane could be installed to prevent further leakage.

If the steps are precast and still in reasonable condition, they could be reset and supported with anchors installed above grade or other supports that don't require drilling a hole all the way through the foundation. If the steps are damaged, replacement with new concrete or treated wood alternatives will improve the situation.

In the unusual case where you find the steps are in good condition, do not appear to have pulled away from the foundation and there is no substantial gap along the foundation wall, interior repairs may be warranted. Filling holes or small cracks in foundation walls with injectable compounds is a common way to prevent periodic seepage. The most commonly used material is epoxy, but there are other sealants that may be equally effective.

There are several local companies that will come into your basement, drill or chisel the openings to make them more accessible and pump one of these compounds into the holes under pressure until they are filled. Once this material cures, it should seal and prevent further leakage through the gaps.

The only possible downside to this method is the bolts might continue to corrode and leakage could recur through the rusted-out bolts. If that happens, the bolts would have to be removed, but it would likely be preceded by the steps sinking or moving away from the home as the bolts deteriorated.

While many homeowners experience periodic leakage through their foundations due to cracks, deteriorated damp-proofing and weeping tiles, yours appears to be a much simpler problem. No matter what you discover about the location of the leaky bolt holes, filling and sealing these openings should solve the problem. Whether exterior work, which may include moving or replacing the steps, or interior repairs are needed, the nuisance of a leaking foundation should be eliminated once and for all.

Ari Marantz is the owner of Trained Eye Home Inspection Ltd. and president of the Canadian Association of Home & Property Inspectors-Manitoba. Questions can be emailed to the address below. Ari can be reached at 204-291-5358 or check his website at



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