An unsealed crawl space in a humid continental climate like Cortland is a pipe for ground moisture into the whole house above it. Air inside a crawl rises through subfloor gaps by stack effect, and that air carries whatever humidity, mold spores, and radon are in the crawl straight into the living space. A properly encapsulated crawl cuts indoor humidity by 15 to 25 percent, eliminates the musty smell that follows every spring thaw, and stops the joists from rotting at the sill plate where condensation drips from cold rim joists in winter.
The right scope in Cortland is full encapsulation, not partial. That means a continuous 20 mil reinforced vapor barrier over the ground with 6 inch overlapped and taped seams, the barrier run up the piers and foundation walls and mechanically fastened near the top with a termite inspection gap, foundation vents sealed with rigid foam block and sealant, rim joists spray-foamed with 2 inches of closed-cell polyurethane, and a dedicated crawl-space dehumidifier plumbed to a condensate drain or pumped to the sump. Partial encapsulation, like a cheap 6 mil poly on the ground with vents still open, is 20 percent of the work for maybe 30 percent of the result.
Trumbull County glacial till crawl spaces almost always have standing water during spring thaw and early summer thunderstorms. Before encapsulation, that water has to go somewhere. We install a crawl-space perimeter drain tied into the home's sump, or a dedicated crawl sump pit in the lowest corner, before the vapor barrier goes down. Encapsulating a wet crawl without first solving the water source is a $6,000 mistake, the vapor barrier traps the moisture, mold blooms under it, and in 18 months the whole install has to come out and go back in.
Rim joist air sealing is the piece most contractors skip and it is the piece that pays back the fastest on energy bills. Cortland winters run teens to 20s and a leaky rim joist leaks 20 to 30 percent of a home's winter air changes. We spray 2 inches of closed-cell polyurethane foam along the entire rim joist perimeter after the vapor barrier is up the wall, which seals the air leaks and brings the R-value to about R-13. Homeowners typically see a 10 to 15 percent reduction in winter gas bills in the first full heating season after the install.
What we handle
Full Crawl Space Encapsulation
20 mil reinforced vapor barrier over ground and up walls, foundation vents sealed, rim joist spray foamed, dedicated crawl dehumidifier with condensate drain. The complete scope for a chronic damp Cortland crawl.
Crawl Space Drainage Pre-Encapsulation
Perimeter drain tile or crawl sump pit installed in the crawl before vapor barrier goes down. Solves the water source so the encapsulation seals a dry crawl, not a wet one.
Rim Joist Spray Foam and Air Seal
2 inches of closed-cell polyurethane foam along the entire rim joist perimeter, seals winter air leaks and brings R-value to about R-13. Can be done on its own or as part of full encapsulation.
Crawl Space Dehumidifier Install
Dedicated 70 to 150 pint commercial-grade dehumidifier mounted off the ground in the crawl, plumbed to a condensate drain line or sump. Holds crawl humidity at 50 percent year-round after encapsulation.
Mold Treatment and Joist Cleaning
Antimicrobial treatment and mechanical cleaning of mold on floor joists, subfloor, and rim joists before encapsulation. Pre-work scope that gets the crawl clean before the barrier seals it in.
Crawl Space Access and Door Upgrade
Insulated airtight crawl access door at the exterior or interior entry, replaces leaky wood or vented hatches. Finishes the seal on a full encapsulation install.
How the job goes
1. Phone Intake and Crawl History
You call, tell us whether you have standing water, standing humidity, visible mold, or a musty smell upstairs. We give you a price band and schedule the on-site walk, usually same day before 2 PM.
2. On-Site Inspection with Hygrometer
Tech crawls the full space with a hygrometer and moisture meter, maps water sources, checks joist and subfloor condition for rot and mold, measures linear feet of perimeter and square footage of ground. Inspection runs 60 to 90 minutes.
3. Written Quote and Scope Decision
You see a written quote by end of day with drainage scope first (if water is present), then vapor barrier, vent sealing, rim joist, and dehumidifier line items. We tell you honestly whether partial encapsulation is enough or whether you need the full scope.
4. Drainage Install (If Needed)
Perimeter crawl drain tile or sump pit installed first on crawls with any water history. Fresh gravel bedding and pump tested before the barrier day. Takes 1 to 2 days of on-site work.
5. Encapsulate, Seal, Dehumidify
20 mil barrier down with 6 inch taped overlap seams, run up piers and walls and mechanically fastened, vents sealed, rim joist spray foamed, dehumidifier set and plumbed. Full install runs 2 to 3 days after drainage work. Photos and warranty handed over before pack-out.
What's included
- On-site inspection with hygrometer and moisture meter
- Pre-encapsulation drainage work if water is present
- 20 mil reinforced vapor barrier, not 6 mil poly
- 6 inch overlapped and taped seams on all barrier joints
- Vapor barrier mechanically fastened to walls with termite gap
- Foundation vents sealed with rigid foam block and sealant
- 2 inches of closed-cell spray foam on the entire rim joist
- Commercial-grade dehumidifier plumbed to condensate drain
- Install photos emailed day of pack-out
- Transferable written warranty
What it costs
Full crawl space encapsulation in Cortland runs $4,500 to $9,500 for a typical 1,000 to 1,500 square foot crawl. Drainage pre-work adds $1,500 to $4,000 on crawls with water. Rim joist spray foam alone runs $1,200 to $2,800.
| Job | Typical price | Notes |
|---|---|---|
| On-Site Inspection and Written Quote | Free | Standard residential homes in Cortland and the 8 towns we cover. Multi-crawl homes and commercial carry a small drive-and-diagnose fee. |
| Full Crawl Space Encapsulation | $4,500 to $9,500 | 1,000 to 1,500 square foot crawl. 20 mil barrier, sealed vents, rim joist spray foam, dehumidifier. Does not include pre-encapsulation drainage. |
| Crawl Drainage Pre-Encapsulation | $1,500 to $4,000 | Perimeter drain or crawl sump pit installed before barrier. Required on any crawl with a history of standing water. |
| Rim Joist Spray Foam Only | $1,200 to $2,800 | 2 inches of closed-cell polyurethane along entire rim joist perimeter. Priced per linear foot of rim joist. |
| Crawl Space Dehumidifier Only | $1,400 to $2,400 | Commercial-grade 70 to 150 pint dehumidifier installed in an existing partially encapsulated crawl, plumbed to a condensate drain or pumped to sump. |
| Insulated Airtight Access Door | $350 to $850 | Replaces a leaky vented hatch with a fully sealed insulated door, interior or exterior entry. |
Ranges are typical for Crawl Space Encapsulation jobs in Cortland and confirmed with an exact written quote before any work starts.