Under the floor, at the foundation
Crawl Space & Rim Joist Insulation in Levittown, PA
Cold floors and damp smells often start below the main floor. Closed-cell foam handles both.
- Free on-site estimates
- Written quote listing material, depth and R-value for each area
- Air leaks and moisture checked before anything gets covered
Below the Floor, Where Older Houses Leak
Crawl space and rim joist insulation applies to a lot of Lower Bucks County houses even though Levitt's originals sit on slabs. The older homes in Bristol, Morrisville, Yardley and Langhorne have basements or crawl spaces with stone, brick or block walls. Many additions on Levittown houses were built over crawl spaces. Newer homes in Newtown, Northampton and Lower Makefield have full basements with long runs of exposed rim joist. In every case, the band where the wood framing meets the foundation is usually one of the leakiest spots in the house.
The rim joist
The rim joist runs around the entire perimeter of the house on top of the foundation wall. It is often covered with nothing but a loose fiberglass batt, which does almost nothing to stop air. Closed-cell spray foam sprayed directly onto the rim and sill seals the joint, insulates it and adds a vapor retarder in one step. HomeGuide lists rim joist foam at $2,000 to $2,500 for a typical house.
Crawl spaces
An open, vented crawl space pulls humid summer air under the house. Lower Bucks County gets around 50 inches of precipitation a year in many towns, and the river towns sit low. That moisture condenses on cool surfaces under the floor and can wet the wood and the insulation. We look at each crawl space and recommend either insulating the floor above it or sealing the crawl space and insulating its walls with closed-cell foam, with a vapor barrier over the ground. HomeGuide lists crawl space encapsulation at $3 to $10 per square foot.
Additions over crawl spaces
Many Levittown family rooms and bedroom additions sit on short crawl spaces with little access. These floors are often cold in winter. ENERGY STAR recommends R-19 for floors in zone 4A. Where access allows, closed-cell foam on the underside of the subfloor or on the crawl walls is usually the cleanest fix.
Water first
Insulation does not fix water. If a crawl space floods or a basement wall leaks, we tell you before we quote, because foam over a wet wall only hides the problem. Grading, gutters and sump issues come first.
Want us to look under the house? Get a free estimate
What This Covers
Work below the main floor.
Rim joist foam
Closed-cell sprayed on the band joist and sill around the perimeter.
Crawl space wall foam
Closed-cell on the foundation walls of a sealed crawl space.
Ground vapor barrier
Heavy poly over the crawl space floor, lapped and sealed.
Vent sealing
Closing foundation vents when the crawl space is sealed.
Floor insulation
Insulating the subfloor over a vented crawl or open porch.
Basement wall insulation
Foam on concrete or block walls before framing a finished basement.
Published Crawl Space & Rim Joist Costs
| Job | Range and source |
|---|---|
| Crawl space, spray foam | $2,000 to $4,000 (HomeGuide); $1,000 to $5,900 (Fixr) |
| Crawl space encapsulation | $3 to $10 per sq ft, $3,000 to $15,000 (HomeGuide) |
| Crawl space vapor barrier | $1,200 to $4,000 (HomeGuide) |
| Closed-cell on crawl space walls | $2 to $5 per sq ft (HomeGuide) |
| Crawl space vent sealing | $150 to $450 (HomeGuide) |
| Rim joists, spray foam | $2,000 to $2,500 (HomeGuide) |
These are HomeGuide (2026) and Fixr (2025) national figures. Perimeter length, wall height, access, standing water and prep change the total. We measure first, and the written estimate we hand you is the price.
How It Works
1. Look under the house
We check access, moisture, wood condition, vents and any existing insulation.
2. Plan
Floor insulation or a sealed crawl space, with the reasons, in writing.
3. Prep
Debris out, loose insulation removed where needed, surfaces cleaned.
4. Seal and insulate
Rim joists and walls sprayed; vapor barrier and vent seals installed.
5. Review
We show you the finished space with photos if access is tight.
Why Choose Us for Crawl Space & Rim Joist Insulation
Moisture checked first
We look for water before quoting insulation.
Closed-cell where it counts
Rims and crawl walls get foam that resists moisture.
Access handled
We plan around tight crawl spaces and tell you what is reachable.
Crawl Space & Rim Joist Insulation Questions
Should I insulate the crawl space floor or the walls?
If the crawl space holds ductwork or plumbing, sealing it and insulating the walls usually works better. If it is a simple, dry vented crawl, insulating the floor above can be enough. We explain the choice for your house.
Why spray foam the rim joist instead of using batts?
Batts do not stop air, and air is the main problem at the rim. Closed-cell foam seals and insulates in one layer and slows moisture.
Does crawl space encapsulation stop mold?
It cuts the moisture that feeds mold by keeping humid air and ground moisture out. Existing mold or wet wood should be dealt with first.
My Levitt house has no crawl space. Does this apply?
Maybe not for the original house, but often for an addition built over a crawl space, or a porch enclosed into living space. We check those on the visit.
Crawl Space & Rim Joist Insulation Service Areas
- Spray Foam Insulation in Levittown, PA
- Spray Foam Insulation in Bristol, PA
- Spray Foam Insulation in Bensalem, PA
- Spray Foam Insulation in Fairless Hills, PA
- Spray Foam Insulation in Morrisville, PA
- Spray Foam Insulation in Yardley, PA
- Spray Foam Insulation in Lower Makefield, PA
- Spray Foam Insulation in Newtown, PA
- Spray Foam Insulation in Langhorne, PA
- Spray Foam Insulation in Croydon, PA
- Spray Foam Insulation in Feasterville-Trevose, PA
- Spray Foam Insulation in Northampton Township, PA
- Spray Foam Insulation in Warminster, PA
- Spray Foam Insulation in Doylestown, PA
- Spray Foam Insulation in Warrington, PA
Get a Crawl Space & Rim Joist Insulation Estimate
Tell us what is under the floor: basement, crawl space or both. We will look and price it in writing.