Do I Need a Vapor Barrier Under My Shed or Portable Building?

For a properly prepared, well-drained site, a plastic barrier usually is not needed. A dry location and the right support are the place to start.

Start with a dry, well-drained site

Choose a location where water drains away from the building. Avoid low spots, standing water, and ground that stays wet. A sheet of plastic is not a substitute for correcting a drainage problem.

How the building sits matters

Portable buildings sit on skids that raise the floor above the ground. This space allows air to circulate underneath, which can help moisture dry. Depending on site conditions and the required setup, the skids may be supported on suitable ground, blocks, gravel, or concrete. We recommend blocks, a properly prepared gravel pad, or concrete for a stable setup.

What happens to the grass underneath?

Grass beneath the building typically dies back when it no longer gets enough sunlight. You can usually mow close alongside the installed building to keep the surrounding area tidy.