Unreinforced Concrete

Like the wood framing, we knew there were problems with the concrete foundation the moment it was exposed. The demo contractor had seen it many times before and was quick to point out that the concrete slab (floor) in the basement didn’t look right. I had known before demo that there was a section that was sloped significantly but believed it was because it had once been an outdoor porch. With the framing gone it became clear the problem was larger than previously thought. One section, that had been covered with a wood floor, was simply dirt (no concrete at all). We made a decision to remove it and by the following morning the slab was demoed and removed. Some of it, by the way, was 1 1/2 – 2″ thick!

That was done so it was time to say goodbye to the orange monster and bring in some smaller equipment to grade the site, dig for the new portions of the foundation and prepare for the pin piles. As the soil was being moved around we noticed new cracks in the foundation and old ones were widening. It was a major problem and we were quickly entering our first major crisis of the project.

The crack above existed before demo but was much smaller. After some investigation I determined that this corner had sunk over 3″! More cracks developed and others widened. Some of it was due to the weight of the smaller machine compacting the soil and some was due to removing the existing wood structure, which was tied it together. No matter what the reason, the back half of the foundation had completely failed and needed to be reengineered. The original plan was to drive pin piles (more about this later) and attach it to the foundation with large steel brackets. Unfortunately the foundation was far too gone to proceed with that plan.

I took many pictures, sketched up some drawings of the current conditions and sent them off to the structural engineer to help devise a new plan. There was much back and forth, a couple of visits from the geotechnical engineer and some serious buyer remorse. After roughly a month we had a plan and were back on track. The sun rose again!

One thought on “Unreinforced Concrete

  1. Wow! This is going to be good reading. I’ve enjoyed the first four parts of the drama. DO NOT TAKE ME OFF YOUR MAILING LIST!!!! I like the way you so carefully explain all the steps and include photos to clarify.

    The previous owners maybe would not have slept well at night if they’d know how poorly their house was constructed. It’s hard to believe wood over dirt. I’m amazed termites hadn’t saved you the trouble of demolishing it.

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