Cracks in Floors and Walls

What should I do about cracks in my basement floors and walls?
Hairline cracks are common in concrete. Concrete shrinks as it cures. This shrinkage is the major cause of cracks in concrete. Most of these cracks are small. The cracks may not extend through the floor slab, or wall. If the size, width, and length of cracks is substantial, rather than hairline, then there may be some cause for concern.

If the crack is greater than 1/8 inch and appears to go through the wall or slab (as opposed to being on the surface), there is the potential for water to enter through it. Whether there will be a water problem depends not only on the crack, but also on the amount of water in the soil pressing against it, on the type of drainage that was installed when the house was built, and on the grade of the land around the house.

Damp Basement Walls

Will water proofing paints help dry out basements?
Most basement water proofing paints can help if moisture is moving through the walls. They help by making the surface less porous so that moisture from wet ground outside is less likely to flow through the wall. They aren’t effective at stopping leaks. Before considering a damp proofer it is important to determine if the water is coming through the wall on condensing on the surface. Taping a piece of clear plastic to the wall can help you decide. If water develops behind the plastic than a damp proofer may help. If the water is on the room side surface that the source of the moisture is probably condensation and a dehumidifer may be the answer. Consumer Reports did some tests of basement waterproofing coatings which is reported in the June 2002 edition. They found that products varied widely in their effectiveness.

Hiring a Water Proofing Contractor

How can we find a competent contractor to repair leaks in our basement?
If you have serious basement water problem. First, check to see if the problem is due to poor surface drainage or gutters. If you don’t think surface drainage is the problem consider hiring a home inspector to help diagnose the problem. This person can give you an unbiased diagnoses of the problem, since he or she would not be doing the work. If it appears that you need to hire a water proofing contractor invite at least three contractors to give you bids. For any contractors you are seriously considering ask for a list of customers you can contact. Ask the reference customers if the work done by the contractor solved the problem, whether it created other problems and if the work was done for the amount originally estimated.

See Also: Home Health Hazards > Radon

Preventing Basement Window Well Leakage

What can we do to stop water from pouring into our basement through the window well?
The first step is to keep water from getting into the window well. It is important that gutters direct water away from the foundation. Extensions on the down-spouts to carry the water at least 5 feet from the house, ten feet or more if practical, should help. Gutters collect water from the large surface area of the roof, and as a result they can carry quite large quantities of water. The grading of the land around the foundation should keep surface waters running away from the house. The back fill around a house can settle considerably in the years after construction. Addition of soil around the foundation can help improve the grade. With a narrow side yard it may be necessary to add a swail which will help carry the surface waters toward the storm sewers in the street or deep into your back yard where they can not collect in the window well. If the prevailing winds actually drive rain water into the window well, a plastic cover should be placed over it. Tiling and addition of gravel should be a last resort which should be unnecessary if you try the down-spout extensions and grading solutions.

Preventing Water Seepage 

How do I keep water from coming into my basement where my driveway butts against my house?
If a drive or sidewalk is either extremely flat or slopes toward the house, you have several choices. You can replace the pavement and correct the grade in the process. If it is concrete, you can have it mud jacked which usually costs about half as much as replacing the concrete. You can also add an additional layer of pavement next to the house to reverse the slope. If you do the latter, you will need to also caulk joints and cracks in the drive or sidewalk so that water which pools on the surface doesn’t penetrate and end up in the basement.

We have water in our basement after a rain, what can we do?
If the water appears during the rain or immediately afterward, it is probably a surface water problem that you can fix yourself. Start by checking your gutters and down spouts to be sure they are leading water away from the house. Then, check the slope of the soil next to the house adjacent to areas where water is entering. The surface should slope away from the house for several feet. If it doesn’t, add soil so that it does slope. If the soil is already at the top of the foundation, you may need to remove soil several feet away from the house to create a swale or gentle trench to carry the water down slope away from the house. If you have grading problems such as these and they are too big for you to handle yourself, then a landscape contractor would be the person to call. The cost would depend on the size of the job, but even a small job could be several hundred dollars. If surface water is not the problem than a tile system near the wall is one solution. One option is to remove a strip of floor along the perimeter of the basement and install tile in a bed of stone and then replace the concrete that has been removed. Another solution is to install small weep drains through the block. These drain into a trough that carries the water to a sump well. In either case a sump pump or some other means to drain the water from the basement will be required.

Protecting Sand Stone Basement

How can deterioration of a sandstone foundation be stopped?
Sandstone usually deteriorates because water is penetrating it from the outside. The deterioration shows up as crumbling of the surface. The first step should be to check the surface drainage around the house. The land should slope away from the house noticeably for several feet and the gutters and down spouts should direct water running off the roof several feet way from the foundation. If you are sure that surface water is not collecting along the wall, you will need to dig down along the wall and apply a water proofing treatment to the outside of the foundation. Treating from the inside could trap water in the stone and cause more rapid deterioration.

Stopping Flaking and Dust Accumulation

The concrete on my basement floor continually creates dust. What can I use to seal it and stop the dust accumulation?
According to the director of the International Concrete Repair Institute this situation is common on basement floors. When concrete is curing in a confined space, there may not be sufficient oxygen. Instead, carbon dioxide combines with the cement, causing carbonation, which in turn results in a weak surface and the dust you describe. He recommends using a sodium silicate sealer to harden the surface. Such sealers are available from various manufacturers. He stressed that it is important to remove as much dust as possible and to roughen the surface so the sealer can penetrate. You should be able to obtain the sealer from a company that sells concrete additives.

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