dfreund
August 7, 2023, 5:57pm
21
Its hard to tell but that is a cobweb.
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dfreund
August 7, 2023, 6:07pm
22
Brian Hoefer:
supported by four 4x4 wood posts in the crawlspace. So, I ran the calculations and was surprised to find out that whereas the (albeit) narrow chimney weighed a few thousand pounds, the combined posts were able to support almost 20,000 lbs.
Yes its amazing what you learn when you run the numbers. I learned from my neighbor who moved houses how much load a vertical 2x4 can carry which surprised me. As a machinist, when engineering or reengineering a design, I would use the machinist bible to reference clamp loads of machine screws. Its amazing how much clamp force a small screw can provide…for example:
dfreund
August 7, 2023, 6:22pm
23
Darren Tews, P.E.:
That’s an unbalanced cantilevered slab. They do exist, but not like this. The footings required for these things have to resist overturning, and the stem wall has to resist bending. So relying on the existing stem wall and whatever footing it has is a big no-no.
The whole thing looks ad-hoc to me. I really doubt an architect was involved.
In addition, it looks pretty old. And this is a good lesson for home inspectors. There’s a bedrock concept in structural engineering that structures have to withstand the test of time. This assembly has not. There is a long crack near the point of highest moment that somebody tried to repair with epoxy. The crack is above grade and not anywhere near the cold joint along the top of the original foundation. Did the cantilever cause the crack? Unknown, but it’s located near the point of highest moment, at the outer fiber where you’d expect a crack. If it were me, I would be letting my client know that if he really wants the property, a repair is in order. Simplest thing to do is one or two piers.
Great feedback Darren, thanks so much!
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