Warmer floors, fewer drafts
Crawl Space & Rim Joist Insulation in Grand Junction, CO
Seal the bottom of the house where cold air gets in.
- Free on-site estimates
- Foam type, inches and R-value written out per area
- Air leaks, ducts and moisture checked before we insulate
Fixing Cold Floors from Below
Crawl space and rim joist insulation is often the most noticeable upgrade in a Grand Junction house. Many homes in the valley, especially ranches and split-levels from the 1950s through the 1980s, sit over crawl spaces. In winter, when average January lows sit around 17F, cold air moves in through foundation vents, around the rim joists and through gaps in the floor. The result is cold floors, drafty lower rooms and pipes at risk in a hard freeze.
Rim joists
The rim joist is the band of framing that sits on top of the foundation wall and holds the ends of the floor joists. In most houses it is just a single board between the outdoors and the crawl space or basement, with a lot of small gaps along the sill. Closed-cell spray foam on the inside face of the rim seals those gaps and insulates in one step. HomeGuide puts spray foam on rim joists at $2,000 to $2,500. It is one of the best values in a cold-climate house.
Two ways to treat a crawl space
Insulate the floor. Keep the crawl space vented and insulate the underside of the floor, ideally to the R-30 the 2021 IECC lists for Zone 5 floors. This works when nothing that can freeze, like water lines or ducts, runs through the crawl space.
Seal the crawl space. Lay a ground cover, seal the vents, and insulate the foundation walls with closed-cell foam. The 2021 IECC lists R-15 continuous, R-19 or R-13 plus R-5 continuous for crawl space walls in Zone 5. This brings ducts and plumbing inside the warm envelope, and is usually the better choice when they are down there. HomeGuide lists closed-cell on crawl space walls at $2 to $5 per square foot.
Dry climate, but still check moisture
Grand Junction gets only about 9 inches of precipitation a year, but crawl spaces can still be damp from irrigation, leaking pipes or poor grading. The Colorado Geological Survey also notes collapsible soils in parts of the region, which can settle when wetted. We check the soil, the framing and the plumbing before insulating, and point out water problems that need fixing first.
Basements
Houses with basements have the same rim joist issue, plus walls that may need insulation. The 2021 IECC lists R-15 continuous, R-19 or R-13 plus R-5 continuous for basement walls in Zone 5. Closed-cell foam on the rim and the walls is a common combination.
What This Covers
We pick the approach after seeing what runs through the space.
Rim joist foam
Closed-cell sealing the band joist and sill.
Crawl space wall foam
Closed-cell on foundation walls in sealed crawls.
Floor insulation
Insulating the underside of the floor in vented crawls.
Ground cover
Heavy poly over the soil, sealed at seams and walls.
Vent sealing
Closing foundation vents in sealed crawl spaces.
Basement walls
Closed-cell or other insulation on below-grade walls.
Published Crawl Space & Rim Joist Costs
| Job | Range and source |
|---|---|
| Rim joists, spray foam | $2,000 to $2,500 (HomeGuide) |
| Closed-cell, installed | $3.00 to $5.00 per sq ft (HomeGuide) |
| 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) |
National ranges from HomeGuide's 2026 spray foam and crawl space guides and Fixr's 2025 guide. Rim length, wall height, crawl access and any cleanup set the total. The written estimate we give you after looking is the price.
How a Crawl Space Job Runs
1. Inspect
Check soil moisture, framing, plumbing, ducts and pests.
2. Recommend
Floor insulation or a sealed crawl, with reasons.
3. Prep
Remove debris and fallen batts; fix small items we agreed on.
4. Install
Foam the rims and walls, lay the ground cover, seal vents as planned.
Why Choose Us for Crawl Space & Rim Joist Insulation
Rims included
We do not insulate a crawl space and skip the rim joists.
Plumbing protected
We plan around pipes that could freeze.
Moisture checked
Water problems get named before we insulate.
Crawl Space & Rim Joist Insulation Questions
Why are my floors so cold in winter?
Most often the rim joists and crawl space are unsealed and uninsulated, so cold air moves in under the floor. Sealing the rims and treating the crawl space usually fixes it.
Should I seal my crawl space or insulate the floor?
If ducts or water lines run through it, sealing the crawl space and insulating the walls usually works better. If not, insulating the floor is simpler.
Is rim joist foam worth it by itself?
Often, yes. It is a relatively small job that closes one of the leakiest parts of the house.
Do crawl spaces here need a vapor barrier?
A sealed crawl space needs a ground cover. Even in a dry climate, soil gives off moisture.
Crawl Space & Rim Joist Insulation Service Areas
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Get a Crawl Space & Rim Joist Insulation Estimate
Ask us to look at your crawl space and rim joists, and we will price the fix in writing.