DIY: Fixing a Foundation Crack

A crack in your foundation could be indicative of a major structural issue, or merely some minor settling in your house's foundation. Before doing anything, get an engineer that specializes in foundations to take a look. If that person tells you it's nothing to worry about, patch any cracks to prevent the crack from widening due to moisture damage.

Step 1: Evaluate the crack. If it is wider than one inch, or there are many cracks within the foundation, call a professional for repairs and assessment. Also, if there are several leaks in your basement, you may also need a professional to correct any problems with your foundation before continuing.

Step 2: Make the crack slightly wider using a hammer and cold chisel. Angle the cuts so there is a larger surface area for the mortar to grip upon. In general, you want the inside base of the crack to be wider than the surface area of the crack. This will prevent the mortar crack repair from pushing out from the foundation.

Step 3: Brush out the crack using a stiff bristled brush. Remove any dirt and debris to assure a firm seal. Lightly mist the foundation crack with water from a spray bottle.

Step 4: Mix mortar according to the directions outlined by the manufacturer. Pay particular attention to the ratio of water and mortar mix. Too much or too little water in relation to the mix could ca

Step 5: Push the mortar into the crack with a trowel. Pay particular attention, making sure that you're forcing the mortar deep into the crack.

Step 6: Smooth the surface of the foundation crack patch with the trowel. Allow the foundation crack area to cure before continuing, plan on waiting at least one week.

Step 7: Seal the area around the foundation crack as well as the crack itself with a concrete sealant used to protect against water damage and provides some level of protection against water permeating the concrete. Apply two coats with a paint roller, waiting 8 hours between coats.