Houses near the Hackensack River and the Meadowlands, in towns like Secaucus, Little Ferry and Moonachie, sit on low, wet ground. The crawl space or basement smells damp, the floor above it is cold in winter, and the rim joist shows dark staining or mold. That moisture does not stay below. It rises into the living space, soaks into any insulation that is down there and keeps the floors cold.
We handle the moisture first and the insulation second. A crawl space gets a continuous vapor barrier over the ground and up the walls, sealed seams, a sealed and insulated rim joist and, where the air stays humid, a dehumidifier. For existing homes the targets are R-10 to R-15 continuous on crawl space and basement walls, and R-25 to R-30 on a floor over an unheated space.
What's included
- Inspection of the crawl space: standing water, drainage, framing condition, existing insulation and any mold on the rim joist.
- Cleanup of debris and old, damaged insulation so the vapor barrier sits on a clean surface.
- Heavy-duty vapor barrier over the ground and up the walls, with seams and penetrations sealed.
- Insulated walls at R-10 to R-15 continuous, or a floor over an unheated space at R-25 to R-30, depending on how the space is built.
- Rim joist sealed and insulated with foam, listed as its own line.
- A dehumidifier sized to the space, when the air stays humid after sealing.
- Sealed and insulated access door.
What it costs in North Jersey
Typical range
$5,000 to $12,000 per crawl space
Crawl space encapsulation and insulation typically runs $5,000 to $12,000 per crawl space. Foaming the rim joist typically adds $800 to $2,000, and a dehumidifier typically adds $1,200 to $2,000.
If the project includes basement walls, rigid board or closed-cell foam typically runs $3.00 to $6.00 per square foot of wall. If mold is found, we deal with it before any insulation goes in; see our mold remediation page for how that is priced.
What moves the price
- Size and shape: a larger crawl space, or one that is broken into low sections, takes more material and more labor.
- Access: a tight access hole slows every step.
- Condition: standing water, rot or old damaged insulation add work before the barrier goes down.
- Add-ons: rim joist foam and a dehumidifier are separate lines.
How the work goes
- 1
Assessment. We inspect the space, photograph problem areas and look for the moisture source. You get a written scope with ranges.
- 2
Clear and fix. We remove debris and ruined insulation. If we find mold, it is dealt with before the barrier goes down.
- 3
Barrier and insulation. The vapor barrier goes in, seams are sealed, and the walls or rim joist are insulated.
- 4
Dehumidifier. If the space needs one, we install and set it up.
- 5
Walkthrough. Most crawl spaces take one to two days, depending on size and condition. We show you the finished space and the settings on any equipment.
When to choose encapsulation vs insulating the floor
Choose encapsulation when the crawl space is damp, smells musty or shows mold on the rim joist. Sealing the space and insulating the walls keeps moisture out of the framing and keeps the whole space dry.
Choose floor insulation at R-25 to R-30 only when the crawl space is dry and vented and stays that way. If there is any sign of mold, start with our mold remediation service before insulating anything.