Are you curious about how to fix a foundation leak from the outside? Foundation repair is probably not your idea of a fun weekend. However, every property owner should understand as much as possible about their structure’s foundation! Leaks get worse and more expensive to address the longer you put off repairs.
Additionally, foundation leaks let moisture into a structure, often risking framing cracks, mold and mildew, and pest infestations. On the other hand, prompt foundation leak fixes avoid all these costly issues. With that in mind, here’s how to fix a foundation leak from the outside of your property.

First, to fix a foundation leak, you’ll need to identify its location. Second, remember to address the cause of a foundation leak after performing repairs.
Most leaks appear inside a basement in one of these areas:
To fix a foundation leak, you’ll use hydraulic cement. You can find this patching compound at virtually any hardware or home improvement store. Also, you’ll need a bucket or other container for mixing the cement, a trowel for applying it, and thick gloves. You’ll also need a chisel and wire brush for cleaning out the damaged area.
Additionally, check the store for a waterproof foundation membrane or coating. Typically, you can purchase these in long rolls. Note the package instructions for how to cut the membrane and ensure you have the right tools.
Lastly, get sealant tape recommended for the membrane application. The membrane packaging should note the right sealant tape to purchase. Of course, you’ll also need a shovel to excavate around the damaged areas.
Once you’ve pinpointed the leak source on the inside, you’ll need to excavate soil on the outside of the foundation. Ensure you dig deep enough to work comfortably but not enough that the pit becomes dangerous.
First, clean out the leak source with your chisel and then your wire brush. Second, wipe away any resultant dust and ensure the area dries thoroughly. Next, mix your hydraulic cement according to its package directions.
Apply the cement to the top of the damaged area with a trowel, pushing it downward with a smooth motion. Use the side of the trowel to smooth it over and “mop up” any excess cement. However, don’t mix moisture clinging to the foundation into the cement. This risks bleeding and softening of the material.
Also, don’t mix any other material into the cement, as this can also cause it to fall apart. Never assume that adding epoxies or adhesives means a more effective sealant. Instead, apply a smooth and even coating of the cement and let it dry according to its package directions.
Lastly, note that hydraulic cement cures quickly. In turn, it’s only workable for about 10-15 minutes after mixing. To avoid wasting material, mix up small batches as you work.
To apply the waterproof membrane, cut it according to the package directions. If applying more than one piece, ensure there is a two-foot overlay between them. This prevents moisture from working its way between those two pieces.
Also, the membrane should extend two inches above the soil line. This helps block surface water and prevents it from pooling around the foundation. Use your membrane tape to close all its sides and overlay, ensuring a firm and watertight fit. Lastly, replace your excavations.
In addition to moisture coming in from the areas mentioned above, consider some added signs of a foundation leak:
Above all, consider regular foundation inspections for your property. A professional can spot leaks while they’re still small and easy to address. It’s also vital to call an experienced contractor if you cannot spot the leak source or if leaks have become extensive. Their expertise ensures foundation repairs that last.
Lexington Foundation Repair Experts is happy to help explain how to fix a foundation leak from the outside. Hopefully, you found this post informative and practical. If so, be sure to check out our other blog entries, where you’ll find more foundation maintenance tips. Also, if you’re in the area, call our Lexington foundation repair contractors for expert services. We’ll start your project with a FREE inspection and price estimate. Additionally, keep in mind that we stand behind all our work with a full guarantee. Whatever it takes to ensure a strong foundation under your structure, we’re the team to trust. For more information, contact our crew today!