Vapor Barrier Installation in Everett, WA
A crawl space vapor barrier is a sheet of polyethylene laid over the dirt floor. It keeps moisture in the soil from evaporating into the crawl space air, which is where damp insulation, musty smells, and wet framing usually start. In Everett, where the ground under a house stays wet for half the year, it is one of the cheapest and most useful things you can put under a home.
This page covers ground cover installation and replacement. For fully sealed crawl spaces with liners on the walls and a dehumidifier, see crawl space encapsulation.
Call (425) 552-1521
Signs the vapor barrier needs replacing
- Bare dirt showing between sheets or around the edges
- Plastic that is torn, brittle, or bunched into piles
- Clear plastic that has turned cloudy and cracked
- Water pooled on top of the barrier
- Condensation on the underside of the floor or on ducts
- No ground cover at all
Request an estimate
- Tell us what’s wrong. A name, a phone number and what you’ve noticed is enough.
- A local crawl space contractor calls you back to book a look underneath.
- You get a price, and decide whether, and when, to go ahead.
For homes in Everett, Marysville, Arlington, Lake Stevens, Snohomish, Stanwood, Mukilteo and Mill Creek.
What a vapor barrier inspection checks
Before new plastic goes down, the contractor should confirm the ground is ready for it and that water isn't coming in from somewhere a barrier can't fix.
- How much of the soil is covered, and how much the sheets overlap at the seams.
- Tears, holes, and areas where foot traffic has worn through.
- Whether water is sitting on top of the barrier, which points to a leak or drainage problem.
- Debris, rocks, and old insulation that should be cleared first.
- The number of piers and posts the barrier has to fit around.
- Where the barrier meets the foundation walls.
What affects the cost of a vapor barrier
A basic ground cover is one of the less expensive crawl space jobs. These are the things that change the price.
Square footage
Material and labor scale with the area of the crawl space floor.
Thickness of the barrier
Plain 6-mil polyethylene meets code and costs the least. Reinforced 10-, 12-, or 20-mil liners cost more but hold up far better where people crawl through for repairs and inspections.
Removal of the old barrier and site prep
Pulling out old plastic, raking debris, and leveling rough spots can take as much time as laying the new barrier.
Seams, piers, and walls
Lapped seams are standard. Taped seams, wrapped piers, and running the barrier partway up the foundation walls take longer and use more material.
Access
A small hatch and low clearance make it hard to move large rolls of material and slow the job down.
Ground cover rules and conditions in Everett
Washington's residential codes call for a ground cover of at least 6-mil black polyethylene in crawl spaces, with seams lapped at least 12 inches and the edges carried to the foundation walls. Many older Everett homes were built before this was required, and others have a barrier that has been walked on, torn, and never replaced.
The soil under Everett homes stays damp from fall through spring. Without a ground cover, that moisture rises into the crawl space and ends up in the floor insulation and framing. Covering the soil lowers crawl space humidity without changing how the space is vented.
A vapor barrier won't stop liquid water. If the crawl space floods after heavy rain, the drainage needs attention first, and the barrier goes in once the water is handled.
From request to estimate
- Request an estimate and mention whether there is an old barrier down there now.
- A contractor inspects the crawl space and checks for standing water or debris.
- The old barrier and debris are removed, and the ground is raked smooth.
- New barrier is laid with lapped or taped seams, fitted around piers, and secured at the walls.
Vapor barrier installation questions
Is 6-mil plastic enough, or do I need 20-mil?
Six-mil black polyethylene meets Washington code and works fine in a crawl space nobody visits. If plumbers, inspectors, or you will be crawling through regularly, a reinforced 10- to 20-mil liner resists tears and lasts much longer.
Should the vapor barrier be black or clear?
Washington's code calls for black polyethylene. Clear plastic lets light through and tends to break down faster, and it doesn't meet the local requirement.
Why is there water on top of my vapor barrier?
Water sitting on the plastic came from above or from the sides: a plumbing leak, condensation off a duct, or runoff coming through the foundation vents or walls. Find and fix that source. The barrier is only meant to block moisture coming up from the soil.
How long does a crawl space vapor barrier last?
A thin barrier that nobody walks on can last decades. One that gets crawled over for repairs may tear within a few years. Thicker reinforced liners hold up much better.
Is a vapor barrier the same as encapsulation?
No. A vapor barrier covers the soil in a vented crawl space. Encapsulation seals the whole space, with liner on the walls, closed vents, and a dehumidifier or conditioned air. Most Everett homes start with a good ground cover.