1910 Foundation Bolting
North Monrovia, circa 1906
Today our foundation retrofitting and bolting begins with a Structural Engineer who after inspecting the site draws plans that are submitted to the local building department for approval. The plans specify the specific hardware, bolts, epoxy, concrete mix (usually at least 3000psi), etc. that we use.
In the photo above a new foundation bolt dropping through the sill plate will be encased in the new concrete sister wall. The following photos are a sister wall and foundation bolt retrofit that we did on a 2 story house character home built in 1910 in North Monrovia. The physical job took 3 weeks and a little over 30 yards of concrete to complete.
Visible are the original fieldstone and mortar foundation wall with a 2″ x 4″ wood cripple wall supporting the floor joists. In an earthquake the cripple wall can fall over so part of our job will be to install plywood to
provide sheer strength. Rebar for the new sister wall has been formed and set in the trenched footing area.
Photos #2, 3 & 4
6′ high sister wall with keyed base and sheer wall in furnace room.
New concrete sister wall and sheer wall.