What kind of drainage should I install underneath the shower base?

For proper drainage under a cedar shower base, it’s important to create a setup that keeps water moving away and prevents moisture buildup.

A crushed stone or gravel bed (3–4 inches deep) is a common and effective option, allowing water to drain quickly while keeping the wood elevated.

Alternatively, a pitched concrete pad can also be used, as long as it’s sloped to direct water away from the base and avoid pooling. Whichever method you choose, avoid flat surfaces that trap moisture.