Crawl space
Crawl Space and Rim Joist Insulation in Houston, TX
Most of Houston is on slab, so the houses that do have a crawl space tend to have it for a reason — and it is usually the wettest part of the building.
Free on-site assessment across Greater Houston. A written scope before anything is ordered.
The work
Two different jobs that get called the same thing
The rim joist is the band of framing that sits on top of the foundation wall, around the whole perimeter of the floor. It is a small area and it leaks badly — it is where the floor structure meets the outside world, and it usually arrives at us still open. On a house with a crawl space or a raised foundation, it is usually the highest-value square footage in the building.
The crawl space itself is the volume under the floor. Insulating it is a decision about where you want the boundary between inside and outside to sit: at the floor above, or at the perimeter walls with the crawl space brought inside the envelope.
Getting that decision wrong is how crawl spaces end up damp. We quote one after looking at the drainage, the ground cover and the vents, and the result appears on the written scope with its reasoning attached.
Is this you?
When this is worth doing
Crawl space work earns its place case by case. These are the signs it is the right one.
Floors are cold or damp underfoot
Especially over an unconditioned crawl space in winter.
The house feels humid in shoulder season
Air pulled up from a damp crawl space carries its moisture with it.
Raised or pier-and-beam foundation
Older Houston stock, and the rim joist is nearly always untouched.
On the written scope
What the scope covers
Ventilation and drainage get assessed before anything is sprayed. A sealed crawl space with a water problem is worse than a vented one.
- Written scope, priced With the reasoning for the approach we are recommending.
- Rim and band joist Closed-cell, because this is an area where water contact is possible.
- Perimeter walls or floor above Whichever the assessment supports.
- Penetrations sealed Plumbing, ducts and wiring through the floor deck.
- Existing conditions recorded Standing water, ground cover, vents and drainage, written down before we quote.
- Access and clean-up Including getting our material back out of a space with two feet of headroom.
How it runs
One process, three stages
The assessment matters more here than on any other service we run.
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1
Inspect
Where we can, we want to see the space after rain. Drainage tells you more than framing does.
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2
Scope
In writing, including anything we think needs fixing before insulation makes sense.
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3
Install and verify
Protection through the house if the hatch is inside, a clear route for material, depth checked as we go, and everything we brought in comes back out.
Related
Where to go next
Questions
Asked about this service
Sometimes, and only as part of a properly designed assembly. Closing vents on a crawl space that still has a moisture source makes things worse. That is why the drainage and ground cover get assessed before we quote.
Closed-cell, in almost every case. It sheds bulk water, which matters in a space that can get wet.
Yes, and it is often the sensible place to start. It is a small area with a disproportionate effect, and it leaves the whole-crawl-space decision open for later.
The visit is free. Someone comes out, looks at the building and gives you a written scope and a price, and the decision stays yours.
We work across 48 cities in the eight-county Houston–Galveston area — Harris, Fort Bend, Montgomery, Brazoria, Galveston, Chambers, Liberty and Waller — plus a set of extended project markets beyond it. If you are near the edge of that, call and ask.
From underneath. On a raised or pier-and-beam house we spray closed-cell foam to the underside of the subfloor between the joists and seal the rim joist around the edge. We check the clearance, the ground below and the drainage first, and the written scope says what gets sprayed and how deep.
The rim joist is the band of framing around the edge of the floor, where the floor framing meets the foundation and the outside wall. In older Houston houses it is nearly always left untouched. Closed-cell foam, such as Accufoam CC-HFO, insulates it, and the Department of Energy notes that sprayed foam can fill small cavities to create an effective air barrier.
Mold needs moisture. The EPA's guidance is that the key to mold control is moisture control. Closed-cell foam on the underside of the floor covers the subfloor so humid crawl space air does not condense on it, but it does not dry out the crawl space. Foam over a plumbing leak or standing water hides a problem, so we assess the drainage first and tell you if there is a leak or a drainage issue to fix.
Free assessment
Tell us about your building
Someone comes out, walks it with you, and puts the scope in writing before anything is ordered.
- An on-site assessment, with the price written after someone has seen the building.
- A written scope: assembly, system, applied depth, exclusions and price.
- A straight answer when the cheaper system is the right one.