How to Repair Leaks in Basement Floors

A common problem homeowners often find in their homes are leaks in their basement floors. Whether the basement is finished or not, leaks in the floor can cause serious damage that can be costly to repair if not repaired quickly after they are discovered. Not only can moisture from these leaks ruin carpets and wallboard, it can promote the growth of mold and fungus that can grow under the carpet and inside walls. Here's how to repair your basement floor leaks:

Step 1 – Locating the Leak

Typically, a leak in your basement floor can come from a crack in the floor, or from a seam where your concrete floor and foundation meet. Before you can begin to repair the leak, you will need to locate the source of that leak. If you basement is unfinished, it will be less challenging to find it. Where you find pooled water, you will usually find either your leak or a path of moisture from your pooled water to a crack or leaky foundation seam. If you have difficulty finding you leak, clean up the water and then keep a close watch on the floor. You'll soon see where the water comes from. If your basement is finished, you may need to pull up your carpet and pad in order to find your leak.

Step 2 – Preparing Your Surfaces

Certain types, or brands, of sealers and patching compounds cannot be used over painted surfaces. Check the product label to determine if you basement floor or the wall that adjoins your floor is painted, you should check the labels of sealers and patching materials to see if they can be used on painted surfaces. If you are unable to use a product that can be applied over paint, you'll need to remove the paint on the surface where you've located your leak.

Step 3 - Repairing Floor Cracks and Joints

To repair basement floor cracks that are larger than ¼" you'll need to first clean debris and dirt from the crack before applying the concrete patch. Remove all loose concrete debris, using a brush or air hose. For cracks where water exists, you'll need to wait until the leak has stopped before applying the patch. For leaky floor-wall joints, remove dirt and debris from the joint before adding your sealer.

Step 4 - Applying Waterproofing

After your patching compound is applied and is set, you can add your waterproof mix. If your crack or leaking wall-floor joint is still moist, be sure you use a waterproofing material that is water soluble. Otherwise, the waterproofing will not adhere to the edges of your crack or leaky joint. Refer to directions by the manufacturer of the waterproof mix to determine compound-water mix ratio.

Step 5 - Applying Sealer

In applying your sealer, brush it on with a stiff bristle brush that allows you to get the sealer into any cracks or pores. Spread the sealer only on the repaired concrete. No need to apply further than an inch or two out from the leaking area. Allow the sealer to dry, then soak with water. Let it harden overnight, then add a second coat.