How to waterproof a stone foundation
After being hit by 2 floods in 10 months, the first filling the basement to the ceiling with mud and water the second leaving a foot of water with the sump pump working continuously, our stone foundation now has water coming thru between the stones and between the floor and walls during most every rainfall. We have contacted several of the local contractors and waterproofing companies and no one has been able to tell us anything except we can't fix it from the inside which would trap the water in the stone and mortar causing the foundation to fail and we can't dig more than 10 feet away from the foundation on the outside or the foundation will fail. Is there anyway that we can fix this or do we have to live with water and mold forever? Any help would be appreciated.
Re: How to waterproof a stone foundation
Unfortunately, we had this occur with many old homes- old limestone foundations that are now failing miserably. The solution for us here in NW illinois is build 'curtain walls' on the interior. They have now become the most effective way to get dry for us personally and clients. The process runs as follows: We dig a footing along the interior of the wall, with form-a-drain used for the edges. These run to a sump, which we usually have to install as well. Dimplex or equal type waterproofing is installed after we tuckpoint and reinforce the exisiting wall; then we use spray polyurethane (handi-foam or = in the 600bdft kit) agains the waterproofing. We pour the footings, then either build forms to do a 6-8"poured wall, or build walls using concrete block. The top 8-10" is left open for pressure treated framing, and utilies, etc. This also allows to fill block voids with concrete if using hollow block. If a space remains between the exterior of the concrete and the srayed polyurethane, we use pourable foam beads with insect/fungi/mildewacides (borax) to fill any gaps (not usually). Last step is a floor pour- most sites we excavate the basement 24-30" as much as possible for increased headroom. Clean gravel, 2"ridgid, in-floor heat (electric or tube) and a 4" floor slab. Yes, a lot of space must often be sacraficed. But this is often much cheaper than supporting the home on steel beams and removing the entire old foundation to build new.
We usually see these walls lined with stone or spaces transformed in to dens, living, etc because they are so dry. These are not easy jobs for diy, but doing the grunt work in preperation for a crew saves LOTS of money. Most homes only need 1 or 2 walls done, and maybe a portion of the floor- cost is generally 75-100 per running foot of wall, floors are 40-60 sq ft depending on the size and extent. Most old homes here have lead mine tailings cement- breaks out easy, but dirty. Contact a structural engineer- most call these 'curtain' walls, but that depends on the local area and lingo.