Foundation Repair

When you break out the concrete floor in the basement of your old Portland bungalow, be careful! That floor is actually doing some structural work. The concrete foundation walls that were built in the 1920's are not the same as concrete foundation walls built today! For one, those old walls have no rebar! And remember that they are 80+ years old, and possibly just 4-6-in. thick with large aggregate and very little cement in the mix. And I've seen even worse conditions than this...

We took a risk by removing the floor, but we mitigated the risk a little by doing all of the work during the driest part of the summer. In addition, we went around the perimeter of the foundation wall in sections, and poured new footings to support the walls better.


Here you can see the first of the footings that we poured. Notice the black plastic behind the concrete - that is a 6-mil. moisture barrier, and besides being a code requirement it is important because it blocks moisture from coming into the house from the floor. In new basements, we use a special board that gets sprayed with a tar-like substance - here's a picture from a project that I designed in 2006.