Crawl Space Encapsulation in Everett, WA
Encapsulation turns a vented crawl space into a sealed one. A heavy liner covers the ground and runs up the foundation walls, the vents are closed, the rim joists are insulated, and a dehumidifier or a small supply of conditioned air keeps the humidity down. Done well, the crawl space stays dry all year and the house above it smells and feels better.
It is also the most expensive crawl space upgrade, and it isn't the right fix for every Everett home. This page explains what is included, when it pays off, and what drives the price.
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When encapsulation is worth a look
- Musty air that keeps coming back after the insulation and vapor barrier were replaced
- Crawl space humidity that stays high through the summer
- Heating ducts or a furnace in the crawl space
- Condensation dripping from ducts or pipes
- A plan to use the crawl space for storage
- Allergy or air-quality concerns in the house
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 an encapsulation assessment checks
Sealing the crawl space changes how it handles air and water, so the assessment is broader than a vapor barrier inspection.
- Whether water comes in through the walls or from below, and whether a sump pump or interior drain is needed.
- Current humidity and wood moisture readings, to size a dehumidifier.
- Gas appliances in the crawl space. A furnace or water heater that pulls combustion air from the crawl space needs a plan before the vents are sealed.
- The foundation vents and how they will be sealed.
- Existing floor insulation, and whether it will come out or stay.
- Framing damage or rot that needs repair before the liner goes in.
- Where the dehumidifier will drain and plug in.
What affects the cost of crawl space encapsulation
Encapsulation estimates vary widely because the scope varies widely. Ask for a line-item quote so you can see where the money goes.
Floor area and wall height
The liner covers the ground and the walls, so a larger footprint or taller foundation walls mean more material.
Liner thickness
Most encapsulation liners are 12- to 20-mil reinforced polyethylene. Thicker liners cost more and stand up to traffic and storage.
Drainage and sump pump
If water comes into the crawl space, a perimeter drain and sump pump may be part of the job. This is often the largest single line item.
Dehumidifier or conditioned air
A crawl space dehumidifier is a separate appliance with its own purchase price, electrical needs, and running cost. Some homes use a small supply of conditioned air from the HVAC system instead.
Insulation changes and prep work
Moving insulation from the floor to the walls and rim joists, removing old material, and cleaning the space all add labor.
Is encapsulation a good fit for Everett homes?
Encapsulation got popular in the Southeast, where summer air is hot and humid and a vented crawl space pulls that moisture in. Everett's summers are dry and its winters are cool and wet, so a lot of homes here do fine with open vents, a solid ground cover, and good drainage. That combination costs much less than full encapsulation.
Encapsulation makes more sense when that basic setup has been tried and the crawl space still smells or stays humid, when ducts in the crawl space sweat, or when the space has water coming through the walls. Homes on low ground near the Snohomish River or on sites where runoff collects around the foundation are common candidates.
Washington's building code allows unvented crawl spaces when they meet specific requirements for the ground cover, wall insulation, and air conditioning or dehumidification. A contractor who does encapsulation here regularly should know those details.
From request to estimate
- Request an assessment and describe what has already been tried.
- A contractor checks moisture, drainage, appliances, and framing, and recommends either encapsulation or a simpler fix.
- Any drainage, repair, and cleanout work is done first.
- The liner, vent seals, wall and rim insulation, and dehumidifier are installed, and the system is tested.
Crawl space encapsulation questions
Is crawl space encapsulation worth it in Everett?
It depends on the problem. If a new vapor barrier, working vents, and fixed drainage haven't solved musty air or moisture, encapsulation often does. If you haven't tried those basics yet, start there; they cost a fraction as much.
Do I need a dehumidifier after encapsulation?
A sealed crawl space needs some way to control humidity. That's usually a dedicated dehumidifier with a condensate drain, or a small supply of conditioned air from the furnace or heat pump. Sealing the space without either can make moisture worse.
Does encapsulation stop water from coming in?
The liner blocks ground moisture, but it doesn't stop flooding. Water that enters through the walls or rises from below needs a drain and sump pump.
What happens to my floor insulation?
In a sealed crawl space, insulation usually moves to the foundation walls and rim joists, and the crawl space becomes part of the heated envelope. Some contractors leave dry floor insulation in place. Ask how they plan to handle it.
What maintenance does an encapsulated crawl space need?
Check the dehumidifier and its drain line a couple of times a year, clean or replace its filter, and look for tears in the liner after anyone works under the house. If you have a sump pump, test it before the rainy season.