Thursday, April 19, 2012

No More Push-ups...

That Ole' Black Gumbo Clay - standard issue in North Texas!
That ole' black gumbo is our enemy. Looks pretty innocent doesn't it? But with a "potential vertical rise" of anywhere between 3" and 18" it has the ability to pick foundations up and crack them like a pecan! Let me put that in english - when wet, the soil can heave (expand) anywhere from 3" to 18" larger than the size it is when dry. The engineers tell us that the soil's "upward thrust" is 10 tons per square foot! Let me put that in english - in some areas around Dallas that means it can take a ten story building and pick it up off it's foundation supports anywhere between 3" and 18"! No wonder we stay as far away from that ole' black gumbo as we possibly can!

'You mean I paid all that money for this foundation? How can I live on a bunch of concrete beams?'
Gumbo is the reason we've only built pier and beam foundations for all these years. Imagine sitting in your Family Room perched above that nasty old Texas clay some 30", completely isolated from the risks and hazards of uplift. Now imagine sitting in your Family Room on a floor that is a rigid concrete slab laying on something akin to rolling marbles. Which do you think will crack first? The worn out joke amongst the building contractors is that concrete is guaranteed to do three things: get hard, turn gray, and CRACK! It's true! But which foundation stands the better chance of not cracking? 

The almost completed "pier and beam" foundation, ready for the framing members that will span from beam to beam across the waiting piers.
Ahhhhhh, but we have a dirty little secret! A void carton. Huh...a what? Down at the bottom of every form board we position a cardboard box looking thing called a "void carton" that lives in the bottom of the beam between piers that are drilled down into bedrock. Over time the box carton rots away and leaves a void space. When the gumbo swells, it doesn't have anything on which to push. Genius - pure genius!

Sittin' high and sittin' pretty! No "push-ups" for this home!
Many of our client's consider their homes a work of art! How do you think that would look with a big ole' black gumbo crack running right through the center of the picture?

No comments:

Post a Comment