Moisture & Odor Control
Closed-cell spray foam helps halt condensation, damp smells, and mold risks common to Gulf Coast climates.
Crawl Space • Rim Joist • Greater Houston
Crawl Space & Rim Joist Spray Foam in Houston
Your home’s comfort and air quality start at the foundation. Phantom Foam seals the crawl space and rim joist to stop moisture, drafts, and pests—so the floors feel warmer, the air smells fresher, and your HVAC finally gets a break.
Real Air Sealing
Foam expands to fill gaps at the rim joist and band board—where fiberglass can’t actually stop air movement.
Energy Savings
Less infiltration = smaller swings in temp and humidity. Many homeowners report noticeably lower bills.
Cleaner Indoor Air
Seal out dust, pollen, insects, and soil gases that creep in from the perimeter.
Why Crawl Spaces & Rim Joists Need Foam
The rim joist is the band of wood that sits on top of your foundation walls—it’s full of plumbing, wiring, and seams. In Houston’s humidity, those seams pull in moist air. Traditional batts don’t air seal and can even trap moisture against wood. Spray foam combines insulation + air barrier, and closed-cell adds a vapor retarder for better moisture control.
Open-Cell (Interior)
- Great sound dampening for floor cavities
- Budget-friendly; flexible in odd cavities
- Use where vapor control is less critical
Closed-Cell (Foundation)
- High R-value per inch + rigidity
- Acts as a Class II vapor retarder at typical thicknesses
- Ideal for rim joists and crawl space walls
Recommended Thickness & Assembly
- Rim Joist: Closed-cell 2–3" (target code-min R and vapor control)
- Crawl Space Walls (conditioned crawl): Closed-cell 2–3" on interior walls; seal vents
- Floor Above Crawl (if crawl stays vented): Open-cell 5–7" between joists + careful air sealing
- Vapor & Ground: 10–20 mil poly on soil (taped & sealed) when encapsulating; seal piers & seams
We’ll verify local code, HVAC sizing, and moisture conditions before final spec.
Common Signs You Need This
Before
- Cold floors, musty smells
- Visible gaps at rim/band board
- Condensation on ducts or subfloor
- High humidity, pests, or rusting fasteners
After
- Warmer floors & steadier temps
- Noticeably drier, cleaner air
- Quieter spaces above
- HVAC cycles less often
Our Crawl Space Process
- Inspection & Metering: moisture readings, venting, visible mold/rot checks.
- Scope & Spec: open vs closed cell, thickness, ground vapor barrier, vent strategy.
- Prep: mask mechanicals, protect wiring/plumbing, stage ventilation.
- Install: consistent passes, correct lift thickness, perimeter air sealing.
- Encapsulation (if chosen): ground poly + wall seal + column wraps + tape at seams.
- QA & Cleanup: cure check, touch-ups, photo documentation.
Special Conditions We Address
- Existing Moisture/Mold: we’ll remediate or refer before sealing the assembly.
- Termite Inspection Gaps: maintain code-required viewing strips where applicable.
- Combustion Safety: verify clearances and makeup air around gas appliances.
- Ductwork in Crawl: sealing + insulating ducts can deliver huge comfort gains.
Request a Free Crawl Space Quote
Fast scheduling. Weekend options by scope.
Crawl Space & Rim Joist — Frequently Asked Questions
Is spray foam safe for crawl spaces in humid climates?
Yes—when properly specified and installed. Closed-cell foam adds vapor resistance and helps curb condensation that feeds mold.
Do I need to encapsulate or can I just insulate the floor?
Both work, but encapsulation (sealed walls + ground poly) delivers better humidity control and comfort in Houston.
How thick should foam be at the rim joist?
Typically 2–3" of closed-cell for R-value, air seal, and vapor control. We confirm on site.
Will this fix cold floors?
In most homes, yes. Sealing drafts at the perimeter and insulating the assembly warms floor surfaces.
What about termites and inspections?
We maintain inspection gaps per local code and coordinate with your pest provider if needed.
How long does it take?
Many projects finish in a day. Larger/encapsulation jobs may take 1–2 additional days.
Does spray foam help with odors?
By controlling moisture and air movement from the crawl, most musty odors diminish significantly.
Can I foam over fiberglass?
We typically remove deteriorated batts first to avoid trapping moisture and to ensure full adhesion.
Open-cell vs closed-cell — which is better?
For rim joists and crawl walls: closed-cell. For floors/joists in vented crawls: open-cell for depth and acoustics.
Will this reduce noise?
Yes—especially with open-cell in the floor assembly. We’ll size for practical acoustic improvement.
Financing or phased installs?
We can phase scope (rim joist first, then walls/ground poly) and discuss payment options.
Will foam trap moisture in wood?
Not when installed on dry substrates with correct thickness and vapor strategy. We meter before we foam.