Jeff Duntemann's Contrapositive Diary Rotating Header Image

December 15th, 2011:

Basement Hydraulics


Talk about a weird feeling: I stood downstairs in one of the bedrooms after the mudjacking crew had drilled six 1 3/4″ holes through the 6″ slab and down almost two feet into the soil. They stuck a hose as thick as my arm through each of the holes in turn, forcing liquid concrete into the soil. Once all the holes had gotten a dose, the hose was moved to a hole near the north wall, and the crew boss pressed the pump button once, twice, three times.

I watched as the slab rose smoothly, almost half an inch in the space of two seconds. Whoa.

It’s been a messy, dusty, ad-hoc sort of project. In summary: They drill a number of holes through the slab. (In our case it was seventeen.) They pump liquid concrete (“mud”) through a hose into the soil and/or voids under the slab. The voids fill up as the soil rises beneath the slab. Eventually, with no more voids to fill, the pressure of the liquid concrete lifts multiple tons of concrete slab back to where it was before it began to sink. The liquid concrete stabilizes the soil beneath the slab, and with some luck we won’t see the slab settle again.

There were a few weirdnesses. Here and there liquid concrete forced itself up between the slab and the stem walls (and out of a few of the holes as well) like a glistening blob in a third-shelf horror movie. The bathtub didn’t quite return to its former position and may have to be pulled and re-set.

Still, as best we can tell, the operation was a success and the patient not only survived but rose from the dead. There’s much mess down there still, with plastic taped up all over the place and my fiction and magazine stacks all boxed and inaccessible, but the flaw that precipitated the whole business has at least been dealt with. Given that we had to empty the rooms completely, we decided to pull the carpet and replace it. And with the carpet gone, there’s no reason not to re-paint. Carol has been meeting with decorators. I’m designing a new layout for the furniture. It will have been a huge amount of work (and way, way too much money!) but when we’re done, the lower level will look very good.

More on the project as it happens. The wind you heard through the pines last night, however, was a massive sigh of relief.