Cinder block foundation walls are hollow, and can fill up with water. That’s why on a french drain system “weep holes” are drilled into the bottom row of the blocks. Without these holes, the block wall can fill up with water and start to deteriorate and erode. If ignored this process can lead to failure of the foundation wall, requiring restoration.
These are the main, basic steps when restoring a cinder block foundation wall due to water erosion:
Above in the picture we excavated down to the footing of the foundation to expose the eroded blocks. We then clean and prep the block wall and check for any loose blocks or concrete and remove those.
After the wall has been prepped and cleaned we fill in all the voids with cement and re-cement the exterior foundation wall. It’s important that the cinder block is cleaned and primed so that a good bond to the old concrete is formed.
After the cement has dried, an adhesive primer is applied to the foundation wall and a sheet rubber membrane is sealed to the foundation wall. This membrane can flex and move and completely waterproofs the cinder block foundation, preventing any future cracks from leaking.
Exterior repairs are a lot of work, it’s always a good idea to go beyond the problem areas and find a stopping point that makes sense.
With good surface prep, and a good bond, an exterior foundation restoration like this should last decades. Do you have block erosion or had it repaired in the past? Leave a comment, or ask a question.