If you're dealing with a crawl space with a thin, torn plastic sheet from the original builder that's doing nothing anymore, Arrow Tight Waterproofing's Crawl Space Encapsulation specialists are ready to diagnose it right and fix it for good — not just patch the symptom.
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Our technicians are trained in vapor-barrier and moisture-control building science, not just plastic sheeting installation — we understand stack effect, dew point, and why sealing vents matters as much as the liner.
We dispatch regionally across Washington, DC, so an encapsulation inspection is typically scheduled within days, not weeks.
Encapsulation is priced by your actual crawl space square footage and drainage condition — quoted after a real walk-through, not a phone estimate.
Wall termination is mechanically fastened and sealed to the sill plate or foundation wall, not just draped and left loose.
We diagnose before we quote, so the Crawl Space Encapsulation scope you approve is built around your property, not a generic package.
We install a 20-mil reinforced poly liner across the entire crawl space floor, running it up the foundation walls to the sill plate and sealing every seam — creating a continuous barrier between the ground and your living space.
Support piers and ductwork get individually wrapped and sealed rather than draped over, which is where most DIY encapsulations fail within a year. This is why our encapsulations hold up years after the crew has left the property.
📞 Get a Free Quote →Foundation vents that were originally designed to 'air out' the crawl space actually pull in humid outside air most of the year — we seal them permanently as part of a proper encapsulation.
Sealed vents only work safely alongside a dehumidification plan, which is why we never sell vent sealing as a standalone service. Getting this part right is what separates a real encapsulation from plastic sheeting laid on dirt.
📞 Get a Free Quote →For crawl spaces with active groundwater, we install a low-profile sump pit and pump sized for confined-space clearance, tied into a perimeter drain channel along the interior footing.
The discharge line routes water well away from the foundation, and the pit lid is sealed to keep the encapsulated space airtight. It's a step a lot of budget crawl space jobs skip, and it's usually why they fail early.
📞 Get a Free Quote →A properly sized crawl space dehumidifier with a direct drain line keeps relative humidity below 55% year-round — the level where wood rot and mold stop being viable.
We size the unit to your actual square footage and ceiling height, not a generic one-size-fits-all model. We won't call a job finished without it, even if it adds a little time to the visit.
📞 Get a Free Quote →Before encapsulating, we probe exposed floor joists and sill plates with an awl to check for soft, rotted wood — because sealing over existing rot just hides an active structural problem.
Any rot findings are documented with photos and a repair recommendation before we proceed with the liner. It's a step a lot of budget crawl space jobs skip, and it's usually why they fail early.
📞 Get a Free Quote →Call +1-866-476-1348 and describe your crawl space concern — musty smell, cold floors, visible mold. Dispatch routes a crew equipped specifically for confined-space encapsulation work.
Crews reach most Washington properties within days of the call, carrying full encapsulation equipment so the assessment can move straight into scoping if you're ready.
Your technician enters the crawl space, checks for rot, standing water, and existing vapor barrier condition, then quotes a fixed price by square footage on-site.
Once approved, we install the full system — liner, sealed vents, dehumidification, and drainage if needed — and hand you a written warranty on the liner and seams.
"Previous owners had put down some thin plastic that was basically decorative at this point. Full encapsulation with the thick liner and a dehumidifier — floors upstairs stopped feeling cold within two weeks.Should have done this the day we moved in."
"Could see mold starting on a couple of the floor joists when we bought the house. They caught early wood rot during the walk-through before sealing anything, which we appreciated — no surprises hidden under the liner.Should have done this the day we moved in."
"Musty smell used to hit you the second you opened the basement door, and it was actually coming from the crawl space below. Sealed vents, new liner, dehumidifier tied to a drain — smell's completely gone now.Should have done this the day we moved in."
"Had standing water under the house every spring. They put in a low-profile sump before encapsulating so it wasn't just sealing over a wet problem. Been dry under there through two full rainy seasons now.Completely different space down there now."
Our Crawl Space Encapsulation coverage spans Washington, DC, with the same certified standard applied whether your property is in Washington or just outside it.
