Sunday, June 14, 2009

Building our own SIPs house. Part 03

Aug 29,2002
Time to pour some concrete!

We decided to go with a post tension concrete slab. High strength steel cables are laid in the foundation. After the concrete is poured and set for a few days, they pull about 20,000psi tension on the cables. The advantages of this method is to GREATLY reduced the uneven settling of the slab. In theory, you could wash out about half the dirt under the slab, and the slab would still stay unbroken. They dig footers in a pattern in the foundation. Lay the cables down. And then pour the concrete. You can see the footers and cables in the photo above.

The concrete trucks are arriving and it is a sweet site. This is the moment when it really feels like it is finally happening. The finishing crew is actually a good crew. No complaints about them, just about that lazy son. There are one or two spots around the foundation where they should have put in a couple of more form boards. It is not a pretty site to see 1/3 of a yard of concrete oozing out from under a form where the land slopes away. Wood 2x's are a lot cheaper than concrete.In this photo you can see if you look close enough at the slight rise in the front porch section to the right. Also, well into the construction, we found that the atrium which is about seven inches lower than the rest of the foundation is very unlevel. I definitely would ask for a few references on the next concrete crew I hire. Also, this was the first foundation for me, so I was not savvy on potential problems to look out for.

I made a mistake. I had always planned to separate the hot and cold water lines before entry into the slab. This would allow for me to put a solar pre heater on the hot water line. These are very capable of raising the water temperature from 67 degrees to +90 degrees before the water enters the house. This would save a considerable amount on utility bills.

I completely forgot about this until much later.


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