How To Seal Water Leaks In The Basement

Remove the moisture and any dirt from the leaking area with a dry cloth. If you are sealing an opening on the outside that is allowing moisture in, make sure the weather is expected to stay dry for the few hours after you have filled in the leak.

Use sealer to safeguard your concrete walls against moisture. Because concrete is porous, water can actually leak right through it. Use a silicate-based penetrating sealer and apply it with either a stiff brush or a garden sprayer. It will come ready-mixed and can be poured into a small, disposable bowl to be brushed on, or it will come as a concentrate to be mixed with water in a sprayer and sprayed on. Some brands come pre-mixed in ready to use spray cans, and although easiest of all methods, this is the least cost effective method of application. Choose which method works for you.

Fill in small cracks in the concrete foundation or walls with the silicate-based penetrating sealer. You might need a few coats of sealer to fill in cracks.

Fill in larger cracks with hydraulic cement. Mix the hydraulic cement in a small, disposable bowl, using the manufacturer's directions, which will only call for enough water to get the cement thick, but not too wet. Use a thick cement mixture and get it as far into the crack as you can by using your hands to push it in. It will dry in about 10 minutes.

Allow all the areas you sealed to dry, and check regularly to make sure water isn't leaking through. If water starts to leak, apply sealant or cement, depending on the area.