Pro tip: I watched a crew in Austin pour a slab without checking the subgrade moisture first.

They just started placing concrete on what looked like dry dirt. A week later, I drove by and saw a huge crack running right across the middle. The ground must have been dry on top but damp underneath, and it sucked the water out of the concrete way too fast. I always spray the dirt with a hose the night before now to make sure it's evenly damp. How do you guys test your subgrade before a pour?

3 comments

3 Comments

lopez.quinn1mo ago

Taylor's boss learned the hard way. That Phoenix heat bakes the top layer into dust, but the ground underneath can still hold moisture. You need to check deeper than just the surface. A simple probe or even digging a small test hole can save a huge headache later. Skipping that step is just asking for shrinkage cracks or worse.

nathan_lopez691mo ago

A moisture meter is the only way to be sure. Poking around with a probe can still miss wet pockets deeper down. That cheap tool saves so much time and money in the long run.

taylor.sean1mo ago

My old boss in Phoenix swore it wasn't necessary... until a patio slab failed inspection.