Home › Services › Crawl Space Mold & Encapsulation › Washington, DC
Serving DC
Vented dirt crawl spaces in a Mid-Atlantic summer are mold factories. Removal, then encapsulation so it stays fixed.
Free inspection in DC
Pick a time on the calendar, or call and we will get you in today.
Pick an inspection timeActive water right now? Call 202-798-7663 instead of booking a slot — mold starts in 24–48 hours.
The physics are simple and they work against you. Open foundation vents pull humid summer air into a space where the ground and the floor joists sit well below the dew point. Moisture condenses onto the wood, the joists and subfloor colonize, and the stack effect pulls that air up into the living space all season.
Cleaning it without changing the space is money burned. The fix is removal, then encapsulation: sealed vents, a fully lapped vapor barrier up the piers and walls, insulation corrected, and a dedicated dehumidifier that holds the space dry year round.
Washington's housing stock is what makes this a District-specific problem. Rowhouses built between 1900 and 1940 sit tight against their neighbors with shared party walls, below-grade kitchens and rentals, and original brick that wicks groundwater straight through the foundation. Add a flat or low-slope roof with a single failed seam, a cellar apartment two feet below grade, and a summer that runs at 70% humidity, and you get the pattern we see most: growth behind the drywall of a finished basement that nobody notices until the smell reaches the first floor.
Pricing
DC jobs tend to sit at the upper end of these ranges. A licensed DOEE assessment, clearance by a separate company, and tighter containment requirements all carry cost that the other two jurisdictions do not always impose.
| Scope | Typical range |
|---|---|
| Mold removal and HEPA treatment of joistsVaries with square footage and access | $1,500 – $5,000 |
| Full encapsulation with 12–20 mil vapor barrierIncludes sealing vents and rim joist | $3,500 – $12,000 |
| Crawl space dehumidifier, installed | $1,200 – $2,800 |
| Sub-slab or perimeter drainageOnly where water is entering, not just humidity | $2,500 – $9,000 |
| Structural repair of rotted joists or subfloorQuoted after inspection | Quoted per scope |
Typical range for this market — not a quote. Every property is different, and the number that matters is the written scope you get after the free inspection.
Code & regulation
Under the Mold Assessment and Remediation Act, mold remediation covering more than ten square feet of a residential or commercial property must be performed by a professional licensed by the Department of Energy and Environment. The Act also separates the two roles: the company that assesses and clears the work should not be the company that performed it. DC is the only jurisdiction in our service area that licenses mold work specifically, and it is worth asking any contractor here to produce their DOEE license before you sign anything.
Removal itself does not pull a permit. The rebuild often does: DC's Department of Buildings requires permits for structural work, and separate trade permits where plumbing or electrical is disturbed — which is common once a basement wall is opened. Cosmetic replacement of drywall and finishes in kind generally does not. We handle the filing where the scope requires it, and we tell you at estimate time whether yours does.
DC housing code treats mold as a habitability defect, and the Mold Act sets a window for a landlord to assess and remediate after receiving written notice from a tenant. Two practical consequences: tenants should give notice in writing and keep a copy, and landlords should get a licensed assessment on the record quickly, because an undocumented delay is what turns a repair into a dispute. We work for either side and the documentation package is the same.
Before we arrive
In order. The first two matter more than everything after them.
Why DC specifically
Washington's housing stock is what makes this a District-specific problem. Rowhouses built between 1900 and 1940 sit tight against their neighbors with shared party walls, below-grade kitchens and rentals, and original brick that wicks groundwater straight through the foundation. Add a flat or low-slope roof with a single failed seam, a cellar apartment two feet below grade, and a summer that runs at 70% humidity, and you get the pattern we see most: growth behind the drywall of a finished basement that nobody notices until the smell reaches the first floor.
How the work runs
No hand-offs, no second contractor to hire for the rebuild, and no testing done by the same people who did the removal.
A licensed technician walks the property with moisture meters and a thermal camera, finds the water source, maps the affected square footage, and photographs everything your insurer will ask about.
You get a written scope and line-item estimate the same day, built in the estimating format carriers expect — plus the photo log and moisture readings that support the claim.
The work area is sealed in 6-mil poly with a negative-air machine and HEPA filtration so spores are not pushed into the rest of the house while we work.
Non-salvageable porous material is cut out and bagged, framing and salvageable assemblies are HEPA-vacuumed and treated with an EPA-registered antimicrobial, then the space is dried to a documented moisture target.
An independent hygienist samples the area and issues a clearance report. We do not test our own work — the document is yours, and it is what a buyer, a lender, or a tenant will accept.
Remediation without repair guarantees a callback. We correct the roof, siding, window, flashing, or grading failure that let water in — then put the drywall, paint, and flooring back.
Straight answers
If the crawl space is dirt-floored and vented, it is usually the difference between fixing this once and fixing it repeatedly. It also typically improves comfort and energy performance on the floor above, since you stop conditioning outdoor air.
Surface treatment without changing the humidity buys you a season. The colony returns because the conditions that created it are unchanged.
Two to four days for most residential crawl spaces, longer where there is structural repair or drainage work in the scope.
What we do
Every service page carries the typical price range, what the code requires in that jurisdiction, and the steps to take before anyone arrives.
Moisture mapping, thermal imaging, and independent lab sampling — so you know what you have before anyone sells you a remediation.
See pricing & steps →Containment, negative air, removal, and independent clearance — with the leak that caused it repaired under the same contract.
See pricing & steps →Stachybotrys handled to the same containment standard as everything else — because the response does not change with the species.
See pricing & steps →The most common mold job in the DMV — finished lower levels built tight against below-grade block, with no drainage correction.
See pricing & steps →Vented dirt crawl spaces in a Mid-Atlantic summer are mold factories. Removal, then encapsulation so it stays fixed.
See pricing & steps →Almost always a roof leak or a ventilation failure. We remove the growth and correct whichever one caused it.
See pricing & steps →24/7 emergency extraction and structural drying — the 24-to-48 hour window where a water loss has not become a mold loss yet.
See pricing & steps →Growth in the air handler or duct liner does not stay in one room — it gets distributed to every register in the building.
See pricing & steps →Free, written, no obligation. If it turns out you do not have a mold problem, we will tell you that and leave — it costs you nothing to find out.