What is the best way to renovate a basement after a flood?
Wren ToombsJune 18, 2018Last updated: July 30, 2020
Hello, I'm in the midst of a post-flood basement renovation and have been doing some reading on your website only recently. I'm realizing that I may have made some mistakes and would like your advice as to what direction to take in order to minimize future problems.
The basement was partially finished when it flooded after a 100mm Ottawa area rain event in October 2017. The home is located 1 KM east of the Rideau River, probably on infill over swampy land. In any case, the water table is high (12-18 inches below the slab). The cause of the flood was undetermined, but I suspect that a rising water table overwhelmed the 1950's era drainage system of exterior clay weeping tile connected to a running trap that evacuated into the sanitary line. We had 12 cm of water on the floor overnight. The basement was divided into two parts, with one half finished and one unfinished. I removed all the flooring in the finished section, cut and removed the gyprock and insulation three feet off the ground, and disinfected the studs throughout.
We decided to replace the sanitary drains and install a backwater valve. At the same time, we had weeping tile placed next to the new drains. The existing slab was left in place, other then where it was chipped out to access the drains. We then considered our flooring options for the finished half of the basement and decided to have a concrete floor for its resistance to future flooding. We had a company pour a new 2-3 inch slab on top of the existing slab over that half of the basement. The 2x4 stud wall that was placed up against the foundation walls was left in place, but protected with Blueskin tape.
We now have to finish the walls and seal or otherwise treat the concrete floor. I understand now that I should've removed the 2x4 stud wall before pouring the new slab. I also see that it would have been better to remove the entirety of the old slab and install a new properly insulated one. My question is can I proceed in a way that makes sense or do I need to start over? I was thinking of acid staining the floor and then applying a sealant, but I now see that this product is not LEED approved.
Thanks for your time reading and any advice you can offer.