PRS: basement waterproofing, part 3

Waterproofing larger and wet cracks

Sometimes the crack repair is a bit more challenging because water starts weeping through as you attempt to fill it with mortar. This is called an "active crack." When you encounter an active crack, more floor or wall preparation must be made.

Use your hammer and chisel to chip into the crack. What you're after is a dovetail-shaped crack. The wide side of the dovetail will be towards the exterior of the basement floor or wall. The narrow side is facing towards the inside. What we're doing here is creating a wedge plug that will seal all the tighter under external water pressure.

Now, fill the crack with mortar

Now that you've finished chiseling the dovetail cut along the length of the crack, make sure you remove all the debris. A wet/dry shop vacuum and a screwdriver are some of the best tools to take care of this. Once it's all cleared out, trowel in your mortar mixture, once again working from one end to the other. Remember our rule: no air pockets.

Use a weep pipe for persistent leaks

Once you've finished the waterproofing repairs, leave plenty of time for the mortar to set up and dry. Come back afterward, preferably after a hard rain, and check your work. All dry? Good! Still leaking? Not so good. Further measures are required; you'll need to install a weep pipe.

The purpose of the weep pipe is to provide permanent water pressure relief. The pipe should stick out of the wall or floor about six inches, and should be mortared into place. Once again, use your hammer and chisel to chip out a hole for the pipe to fit in. PVC is a good choice, since it won't rust.

Connect flexible tubing to the pipe to route the incoming water to a basement drain. If there is no drain available in your basement, a pump may have to be incorporated into the system to raise the water to an available drain elsewhere.

Commercial alternatives to DIY basement waterproofing

Perhaps this is a job you just don't want to tackle: the damage is too extensive, or you would feel more comfortable with a warranty behind the waterproofing. In this case, you can hire a commercial waterproofing company to come in and make a troublesome repair.

There are companies that specialize in just this kind of waterproofing. One popular method is to use a low pressure injection system. The compound injected to seal the crack is usually a proprietary mixture of epoxies, foams, and polyurethanes.

In the long run, keep an eye on it.

Things being what they are, there is always the chance of leaks reoccurring: this is just a fact of life in homes with basements. Keep an eye on it, and make minor repairs when needed.