Renovation & Design
Renovation & Design
Contractor likely best bet for concrete repair
Question: We have a 1986 house with an unfinished basement and exposed foundation with a vertical crack which lets water seep in. What can we do to fix this? Can we fix it ourselves or do we need a professional? If a professional, who do you recommend? I read you article every week, but can’t recall a question such as this. Thanks for your help, Pat.
Answer: Stopping leakage from individual vertical foundation cracks may be possible without disruptive exterior excavation. However, the costs may be similar for professional injection repairs and may not be as reliable.
The typical remediation for foundation cracking is to dig out the soil around the crack, clean the foundation, and cover the area with a liquid foundation damp-proofing or waterproof membrane. Often, a piece of rigid foam insulation, or other sheathing, is applied over the area to protect the repair from future soil damage. The excavation is normally filled with granular material, rather than the existing clay soil, then covered with a layer of topsoil to allow grass or vegetation regrowth. This may be the best way to prevent future leakage as any soil moisture is prevented from entering the breach at the source.
While exterior repairs are preferable, there are often situations where it is not very practical. If there is a large amount of well-established vegetation, such as shrubs, coniferous trees or perennial gardens, then they will have to be removed to dig. Large concrete steps, cantilevered alcoves, garages, sidewalks, driveways, gas meters and fences can all provide a significant impediment to excavating. Some of these can be temporarily removed to facilitate the work, but that will add cost and time. In those situations, interior repairs may be preferable.
The other side to the coin is that interior remediation is likely to have just as many roadblocks as the exterior option. Most foundation walls in our area are covered with wood framing, insulation, and wall sheathing. If the wall covering is taped and painted drywall, or real wood panelling, removal may be very disruptive. There may also be interior partition walls that block access as well as plumbing supply pipes, laundry drains, furnaces, and other mechanical items near the crack. Electrical wiring running through the studs will also have to be avoided when considering fixing the leakage from inside.
For your unfinished basement, with the bare concrete wall fully accessible and visible, repairs from the inside may be the most practical solution. This will normally involve injecting some form of waterproof compound into the entire crack. There may be several types of injections available but the material with the longest track record, as far as I know, is epoxy. Epoxy is an extremely hard adhesive that is created by combining two separate substances and letting them cure. Once it hardens, it should even have more strength than the original concrete. It is resistant to moisture, physical damage and is an outstanding adhesive that will bond extremely well to the old foundation wall.
To answer your second question, it may be possible to do the injection yourself, if you can find the proper product and injection equipment. The epoxy has to be forced into the crack under pressure, which may require some specialized equipment. It may be possible to partially fill the gap with a standard caulking gun, but unlikely that you will succeed in complete coverage, which is very important. You will likely have to inject the epoxy, or at least blow out debris from the crack, using a compressed air system. Prior to this, small holes will have to be drilled at numerous points along the fissure with a hammer drill and masonry bit. The holes will allow the adhesive to penetrate all the way to the exterior side of the foundation wall, critical in ensuring no future leakage. So, if you are an experienced DIYer, prepared to purchase or rent the required equipment, or already have a suitable drill and compressor, then it may be within your reach.
In most cases it will be prudent to call a well-established foundation repair contractor that specializes in injection repairs. Many of the local companies offer this service, but there may be only a handful that have the most experience. Some may try to offer alternative sealants for injection, which may stop the leakage for a certain length of time, but may not be as durable as epoxy. I have seen repairs of this type that have lasted 30 to 40 years without major problems. That may depend on several factors, such as integrity of the surrounding concrete, soil conditions outside the foundation, settlement, and environmental factors. But, the overall factor is often quality of the actual repair. For this reason, I would only hire a contractor that has at least one or two decades of experience with the exact repair and materials used for the crack injection.
The final consideration, as it almost always is with any type of renovation or home maintenance, is the overall cost. As stated above, the overall cost to inject a single vertical crack, which runs from the top to bottom of a standard height foundation wall, may be similar to the fee for exterior repairs. I believe that it is better to do this type of repair from outside, to ensure no water at all leaks into the crack, to prevent future damage from frozen water expansion. Regardless, an interior epoxy injection may be similar in quality and longevity, as long as it is very well done.
Injecting professional quality epoxy into your concrete wall crack may be the most practical solution to stop the water intrusion. You may be able to attempt this yourself, but have a better chance of success hiring a contractor with many years of experience in this type of foundation injection repair.
Ari Marantz is the owner of Trained Eye Home Inspection Ltd. and a Registered Home Inspector (RHI)(cahpi.ca). Questions can be emailed to the address below. Ari can be reached at 204-291-5358 or check out his website at trainedeye.ca.
trainedeye@iname.com
Renovation & Design
Efflorescence on a basement floor due to moisture
Question: I am experiencing a white powder coming up through the basement tiles in my 40-year-old Charleswood home. Can you recommend a cure? Possibly, a sealer that I can purchase and apply myself.
Thanks, Gary D.
Answer: The cure to efflorescence on a basement floor is to find the source of moisture causing it and eliminate it. That may require evaluation of your exterior grading and water management, sump pumps, plumbing supply, fixtures, drains and any other mechanical systems that may potentially leak.
Yours is a very common question that I receive; what is the white powder I see in my basement and how do I get rid of it? As described several times in previous columns, the white powder is known as efflorescence and is simply minerals that leach out from concrete in the form of a salty powder. This typically occurs after the concrete becomes wet and then dries, or from water sitting on many types of masonry products. The water will draw the minerals to the surface of the cement-based materials and leave behind the white, powdery residue when it evaporates. It is essentially harmless, but does provide good evidence that excessive moisture is present, or has been, in the building material it is found on.
There is no way to seal, paint, or waterproof your basement floor to prevent this from occurring, unless the water is coming from a source inside the home and leaking onto the floor. In that instance, the efflorescence should not be your concern, but the item that is actively leaking. In your case, there may have been some mechanical or plumbing component that has been dripping onto the floor. That moisture may have seeped through the gaps between your floor tiles, wet the concrete floor slab below, and caused the salts to rise up beneath the tiles. Once the amount of efflorescence becomes large enough, it will push its way up through the same gaps the water leaking into. Then, the tiles will likely come loose and replacement or securing them is likely.
The first place to look for water leakage may be your plumbing system. Go through the basement and look for any slow dripping plumbing pipes. This could be your supply pipes, likely copper in a house your age, and may also be due to condensation on the pipes. That may occur on cold water supply piping that is too close to a heat source, during humid summer weather, or on hot water supply pipes that may be too close to a source of cold air.
If that is suspected, simply installing inexpensive foam insulation pipe wraps around the offending sections may stop the problem, completely.
That also commonly occurs on the refrigerant lines that enter the furnace plenum from the air conditioner condenser. If they are not well sealed at the junction, or have deteriorated insulation, they will sweat and drip. Either cause may be eliminated by proper insulation and sealing, using easy to install foam pipe wraps and aluminum tape, or other sealants.
While air conditioner pipes may sweat, other items in that system, and high-efficiency furnaces, frequently leak in basements due to their condensate systems. Both the heating and cooling systems will produce large amounts of water during their regular cycles. This water has to be properly drained to a floor drain, condensate pump, plumbing drain, or sump to prevent it from winding up on the basement floor.
This can be inspected by watching the condensate drains while those two systems are operating. If you see water draining properly through the clear, plastic tubing attached, that should be a positive sign. Once the water leaves that hose, it should be immediately directed into a condensate pump beside the furnace, or other proper drain. If there is water on the basement floor in that location, or wet concrete, then something is leaking. Replacing the plastic tubing if it is clogged, cleaning the pump, or securing the end of the hose inside the floor drain may be required to stop the leaking. If it is severe enough, the water may flow to the area under your floor tiles, leading to the issues already discussed.
In addition to the heating system, water heaters and washers are notorious basement components that frequently leak. Water heaters may slowly leak when their TPR valves are damaged or are physically contacted. Storage right beside the tank may cause an inadvertent compressing of the valve release lever. If excessive rust stains are seen near the bottom of the tank, or small drops of water on the floor, call a plumber for immediate replacement, before a larger breach occurs.
For washers, leakage may be caused by loose or damaged hoses at the supply valves, a poorly secured drain hose, one improperly draining into the floor drain, or an amateurishly installed plumbing drain. Older washers may also leak from the inside, which will require a swift replacement with a newer model.
The dryer should also not be neglected in your evaluation, as a poor quality or improperly connected dryer vent can also be a source of significant water vapour. If you have a flexible plastic or aluminum vent, it is easily damaged and may allow warm, humid air from the dryer to leak into the basement. If that air hits a cold window, water pipe, concrete wall, or basement floor, condensation is almost a certainty. Replacing the vent with a solid metal, duct-taped pipe will prevent blockage, damage, and also help your clothes dry quicker.
The final piece of the puzzle may be moisture leaking into your basement through the foundation walls, or from wet soil under the floor slab. Ensuring you have good grading around the house and ensuring rain and snow runoff are directed well away from the foundation walls will help prevent those two things from occurring.
Stopping white, powdery efflorescence from bleeding up from beneath your basement floor tiles will require investigation as to the moisture source behind it. Ensuring none of the plumbing or mechanical systems in your home are leaking, and that water is not seeping into the foundation from outside, are the two keys to stopping the nuisance salts from being present.
Ari Marantz is the owner of Trained Eye Home Inspection Ltd. and a Registered Home Inspector (RHI)(cahpi.ca). Questions can be emailed to the address below. Ari can be reached at 204-291-5358 or check out his website at trainedeye.ca.
trainedeye@iname.com
