Techniques to Repair Cracked Foundation Walls
- Foundation wall cracks are often less serious than they appear.red brick wall with large crack image by Jorge Moro from Fotolia.com
Cracked foundation walls may look dangerous, but often they are caused by failed materials or a slight settling of the house, not to real structural damage. Concrete walls may exhibit a long, hairline crack, while bricks and cinder block foundation cracks usually zigzag through the mortar. Inspect your foundation wall to determine if the crack is serious enough for professional repair or if you can do it yourself. - Use a stiff, wire brush to clean debris out of the crack.drahtb??rste image by Frank-Peter Funke from Fotolia.com
Foundations are prone to becoming wet. Ensure the cracked brick, block or concrete is dry before patching. Dry the area with a hairdryer, suggests This Old House. If the crack is still dry in 15 minutes, proceed with the repair. If moisture returns, there is too much water, and you must let it dry longer, possibly days. For concrete walls, once dry, clean all debris out of the crack by scrubbing with a stiff, wire brush. Sweep or dust off any powdery residue or particles. For brick or block cracks, chisel out old mortar between the bricks, and brush out all debris. - Repair cracks in concrete with polyester resin and fiberglass mesh.reinforcement mesh image by Aleksandar Jovanovic from Fotolia.com
If the crack is hairline or very narrow, consider chiseling out a small amount of material along the crack to make a slightly wider opening to hold more patching compound. Don't chisel away too much, and don't chisel too deeply. Mix patching compound polyester resin with polyester resin catalyst, available at home improvement centers, according to the manufacturer's directions. Brush the resin mixture into the crack, and press fiberglass mesh tape into the resin before it dries. Apply more resin over the fiberglass tape in the crack until it is filled. Allow it to dry at least one hour, recommends Accurate Building Inspectors. - Fill joints with fresh mortar using a flat trowel.Kelle image by reises from Fotolia.com
Brick and concrete block foundations are set with mortar, available at home improvement centers, between the blocks. Use caution when chiseling out old mortar with a chisel and hammer and replacing with fresh mortar. A light touch is best to prevent cracking the bricks and making more cracks in the mortar, explains expert TIm Carter of Ask the Builder. Once old, damaged mortar is removed, mix fresh mortar according to the manufacturer's instructions. Lightly wet the exposed joint with water so new mortar won't dry too fast, which can cause recracking. Fill the joints using a small, flat trowel. Pack the mortar into the joints to ensure that no air bubbles exist, and finish by smoothing the seams to match the rest of the foundation.
