A structure is only as level and lasting as the pad under it. Here’s how a proper base is built so your shed or ADU doesn’t sink or heave.
Strip the topsoil
Organic topsoil compresses and rots — never build on it. We strip down to firm subgrade before anything else goes in.
Build up in lifts
Crushed base goes in 6–8 inch lifts, each one compacted before the next. Dumping a foot of rock and tamping the top is how pads settle unevenly a year later.
Get it flat and draining
- Compact to a firm, even surface
- Crown or slope it slightly so water sheds
- Check level corner-to-corner, not just by eye
When to call a pro
Anything you’ll permit — an ADU, a garage, a big shop — needs compaction and grade you can stand behind. That’s machine-and-experience work, and getting the base wrong is the expensive kind of mistake.
Often Missed
Compact in 6–8 inch lifts, not all at once — a pad can feel solid on top while the middle keeps settling for a year.