Moisture Management of the Crawlspace – Gravel Base

As designers and builders of high-performance homes, we believe in buildings that will remain durable over a long time (like 100 years or more at a minimum). Persistent moisture on wood will eventually lead to rot and failure of joists, sills and posts. Moisture also creates an ideal environment for mold, mildew and fungus which causes poor indoor air quality. Keeping everything dry is the single most important element of durable, healthy buildings.

Our starting point is the installation of gravel below the insulated crawlspace floor so there is a drainage plane underneath the building. Later we install a perimeter drainage system around the exterior foundation walls, but here we are first concerned with the interior area. We installed about 22 cubic yards of 3/4″ drain rock, or a depth of 3 to 4″ throughout the crawlspace.

Our bobcat delivers the gravel from the street to our crawlspace floor.

Freddy spreads the gravel evenly thoughout the space.

Any moisture that might accumulate under the foundation will channel to the drain. See another story about the crawlspace drain.

The first layer of our moisture-managed foundation is completed. On to Step 2: The Vapor Barrier.