We are in earthquake country (Oregon), looking at seismic upgrade on our foundation, which is 115 years old and in dubious condition. Are there options for strengthening a dodgy foundation by installing posts all around the perimeter? So maybe digging out every few feet and reinforcing, rather than digging out all around.

It seems to me that in theory this would work. We just want our house to not fall down in an earthquake - having post-earthquake gaps where the old foundations have collapsed isn't a big deal if the new posts are still holding up the house.

  • Personally, I'd strongly recommend calling around for a qualified inspector and retrofitter. Your home is a big investment, and your life is important too. :) Sep 1, 2018 at 3:59
  • Being an Oregon resident myself I would be more concerned that the foundation is strapped to the mud sill. Keeping the frame of the home on even dodgy foundation will be more effective. Than concrete piers next to the foundation (wooden posts would be a complete waste of time because of termites and carpenter ants). In fact digging next to the foundation may weaken it further. A photo of the foundation may help us provide better answers as this area has everything from large rocks used as pilings, rock foundations held together with mortar to cinder block.
    – Ed Beal
    Sep 1, 2018 at 20:31
  • Ed, that's reassuring. We are about to install Simpson plates to tie the foundation to the mud sill, then proper earthquake plates to tie the mud sill to the rim joist, then whatever's next to improve the tying-in of the rim joist to the floor joists. Those Simpsons are expensive suckers! So knowing that even with a sub-optimal foundation, the work is worthwhile is nice to know. We have researched all this and looked at lots of videos (including the great ones about how not to do it!). Thx.
    – Catherine
    Sep 2, 2018 at 17:21


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