Musty odors reaching your living space, sagging insulation, and visible mold on floor joists all trace back to one root cause: uncontrolled moisture under the house.
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Four commitments that separate a properly trained crawl space encapsulation crew from a generalist showing up with a truck and a hope.
Certification covers proper venting decisions, dehumidifier sizing, and moisture-source diagnosis before any liner goes down.
Local crews carry moisture meters and basic inspection gear on every truck, so the first visit produces real findings, not just a callback.
You'll see a line-item breakdown covering liner, sealing tape, vent covers, and dehumidifier if one is recommended.
Seams are heat-taped or mechanically sealed, and liners are run up piers and foundation walls, not just laid flat on the dirt floor.
Each service below is scoped specifically to crawl space encapsulation, not a generic waterproofing menu with the name swapped in.
A complete encapsulation seals the dirt floor, foundation walls, and piers with heavy-gauge reinforced polyethylene, cutting off the ground moisture that feeds humidity, mold, and wood rot. This is the baseline fix for most crawl spaces showing chronic humidity above 60%.
Older homes with foundation vents are actually pulling humid outside air in during summer months — the opposite of what venting was originally intended to do.
A properly sized dehumidifier, drained to a sump pit or gravity line, keeps relative humidity below the 55% threshold where mold and wood-destroying insects thrive. Units include a humidistat so the system only runs when actually needed, not continuously.
We install a dedicated sump basin and pump sized for the space's water intake, tied into the encapsulation system's drainage channel.
Every encapsulation project includes a joist and subfloor inspection, and we flag any structural concerns before sealing the space, not after.
Four steps, start to finish — from the first call to a sealed, humidity-controlled crawl space.
A quick phone triage helps us bring the right liner mil-thickness and dehumidifier sizing information to the first visit.
You'll get a text confirmation with an arrival window before the technician heads out.
You'll see photos of any wood rot, mold growth, or standing water documented before the quote is finalized.
Encapsulation work carries a written warranty against liner failure and seam separation.
Real feedback from McLean-area customers who called us for crawl space encapsulation.
"The musty smell that used to reach our upstairs bedrooms is completely gone since they encapsulated the crawl space."
"They showed us the mold on the joists with a camera before we ever agreed to anything — appreciated the transparency."
"Dehumidifier they installed keeps the readout right around 45% humidity year-round now. Huge difference from before."
"Sump basin they added handled a heavy rain last month without a drop making it under the new liner."
The questions McLean customers ask us before booking crawl space encapsulation service.
Arrow Tight Waterproofing provides crawl space encapsulation throughout McLean, VA, dispatching from regional staging points to keep arrival times short across our full coverage footprint.
Our encapsulation coverage area grows as we add regional crews, so a past 'outside our area' answer may no longer be accurate.
Notice: Arrow Tight Waterproofing is a free referral service designed to assist homeowners and businesses in connecting with independent local contractors. All contractors and service technicians are independent and Arrow Tight Waterproofing does not warrant or guarantee any work performed. It is the responsibility of the customer to verify that the hired contractor furnishes the necessary license and insurance required for the work being performed. All calls are routed to independent local service providers.
