Vapor barrier installation in Santa Maria CA - a crawl space floor covered wall to wall

Most calls we get at D&M Santa Maria Insulation Company for this work start with a musty smell, damp wood under the floor, or someone finally looking through the hatch and seeing bare dirt. We're based in Santa Maria and work across the cities around it in northern Santa Barbara County and southern San Luis Obispo County, and the price on these jobs mostly turns on how big the crawl space is, how much has to be cleared out, which plastic you choose and whether you want a plain ground cover or a fully sealed crawl space. The schedule follows the same things, plus any drainage repair that has to come first, so the number for your house comes from the estimate I write after I've been underneath it.

We start by clearing out whatever's stored down there, old boxes, scrap wood, leftover pipe, because the plastic has to lie on open ground to cover all of it. Before anything goes down, I go over the two kinds of sheet with you, a thinner plastic and a tougher reinforced one, and I'll steer you to the tougher one anywhere people crawl through to reach the furnace, water heater or ductwork, since that's where thin sheet tears first. Then our crew lays the plastic across the floor, overlaps the seams and runs it up the foundation walls and around each pier so there's no strip of dirt left open at the edges.

A vapor barrier deals with moisture from the ground, not the air leaking through the rest of the house. If rooms upstairs run hot or the house feels drafty, attic air sealing closes the gaps that let air escape before any insulation goes on top. In an older house that's short on insulation, retrofit insulation adds it to the walls or floors, and it's easier to plan while we're already under there.

Before work starts, I check with the building office that covers your address. Inside city limits that's the City of Santa Maria Building Division, and outside the city it may be the county. I don't assume either way whether your job needs a permit, so we ask, and if they say one is needed, we take care of the application and set up the inspections.

The bigger local factor is the marine layer, the wet fog that pushes in off the Pacific most mornings from late spring through summer, which usually keeps the air and dirt under houses here on the damp side. That's why I want the plastic tight to the walls and piers and not just thrown down the middle, and it's the same thing we see on jobs in Orcutt and Nipomo.