Archive for February 10th, 2009

Starting to Set the Rebar

Tuesday, February 10th, 2009

After completing the waterproofing, setting the rebar in place is next. 

Let’s pause for a moment …

Some people have asked us, ‘why is building your foundation so difficult?’  Let us explain.

Foundation Design, In Simple Terms

Given that our house is sitting on a ‘seasonal perched water table’, we need to have a completely watertight basement that is heavy enough to withstand hydrostatic pressures that can be up to 500 lbs per sq ft.  In simple terms, we need to build a:

Concrete boat that is heavy enough to sink
and
strong enough to resist cracking as it sinks.

The rough numbers go like this:

Building footprint      = 3,000 sq ft

Hydrostatic pressure  =  500 lbs per sq ft

Total building weight –> 1.5 million lbs

So, we need to have dead weight of 1.5 million lbs in our concrete boat and it has to be strong enough so it doesn’t break up or crack while it is sinking.

Sounds easy?  Yes.  And expensive.  Ouch!

The strength in the ‘concrete boat’ will come from the steel rebar placed in the concrete.  Thus, Bill Brown’s team is putting the rebar in place, per Duquette Engineerings’ design.  Yes, all to meet the soil engineer’s recommendations (JF Consulting).  What fun …

Placing Rebar

This was the first day of placing the rebar.  The rebar will cover the walls and go over the protection slab (which protects the waterproofing from being damaged by the rebar and construction activities).  The protection slab is 3 inches thick and adds weight to our ‘concrete boat’ so it sinks, even though it is completely waterproof.

Waterproofing completed on the east wall.

Waterproofing completed on the east wall.

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