Rigid foam panels deliver a high R-value in a thin profile, resist moisture, and give continuous coverage that cuts the heat leaking through your framing — the go-to for rim joists, foundation and crawl-space walls, and tight assemblies.
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What It Is
Foam board is rigid panel insulation — stiff sheets of plastic foam that you cut, fit, and seal into place rather than stuff into a cavity. Two things make it stand out: it packs one of the highest R-values per inch of any common insulation, so it does more in a thin profile, and it resists moisture, so it holds up in damp, below-grade, and exposed spots where fiber insulation would sag and fail.
Because the panels form a continuous layer, foam board also cuts thermal bridging — the heat that shortcuts straight through wood or metal framing. That's why it's the natural pick for rim joists, foundation and crawl-space walls, and roofs, and why it's often paired with cavity insulation rather than used alone. It costs more than a fiberglass batt, so it's about using it where those strengths actually pay off — which is what we help you decide.
Types of Foam Board
Rigid foam board comes in three generic types. They trade off R-value, moisture resistance, and cost differently — here's the honest comparison, and we'll match the right one to your job.
The white bead-board panel — the most economical of the three.
The dense colored board (often pink/blue) built for moisture.
The foil-faced board with the highest R of the three.
Is It Right for You?
Foam board is a premium material that shines in specific spots — the places its high R and moisture resistance beat a standard batt.
Rim & band joists
Foam board seals and insulates the rim joist far better than a loose batt that sags and leaves gaps in that leaky spot.
Foundation & crawl-space walls
Below grade, rigid foam handles the moisture and stays put where fiber insulation would soak through and lose value.
Thin space, high R needed
Where you can't add cavity depth, foam board's high R-value per inch squeezes more performance out of a shallow assembly.
Stop thermal bridging
A continuous layer of foam over the framing cuts the heat that shortcuts straight through studs and joists.
Damp or exposed areas
In moisture-prone spots, XPS and polyiso keep performing where batt or cellulose would sag, mat, and fail.
Cathedral ceilings & roofs
In vaulted assemblies with little cavity, rigid boards deliver continuous coverage that cavity insulation can't.
How We Work
Foam board only performs when the panels are cut tight, sealed continuous, and covered to code. Here's how we handle every install.
We inspect the space and your goals — R-value, moisture, thermal bridging — and confirm whether foam board is the right call or a cavity material would do.
We recommend EPS, XPS, or polyiso and the right thickness to hit your R-value and moisture target for the location.
If existing insulation is old, wet, or contaminated, we remove and haul it away so the foam board seats on a clean, sound surface.
We cut the panels to size, fit them tightly, and seal seams and edges so the layer stays continuous — plus a code-required cover where the foam is exposed to living space.
We confirm full, gap-free coverage and proper sealing, clean up completely, and walk you through the finished job.
Why Attic Pros
For over 13 years, Bay Area homeowners and businesses have trusted us for insulation — because we recommend the right material for the job (not just the priciest), install it properly and to code, and stand behind our work.
Real Customers, Real Results
Shah turned my experience around from a bad one to a good one in the very beginning. Aleksandra at the office answered and addressed all my questions and concerns very thoroughly. Jose who did the rodent proofing, answered all my questions and took his time going through the crawlspace and making sure he found and covered all potential access points for rodents into the crawlspace. He was very patient and thorough.
Just had a great inspection from Tom. Very informative and helpful!
Dennis is extremely professional, communicated all that was happening, explained where the critters were invading and did a very thorough job sealing the house, along with his helper. Thank you!
Denis, German,& Alexander were great. Very professional, thorough and customer oriented. I would recommend them for any attic, crawl space, HVAC, insulation, rodent & sub pump work. They were nice, hard working & non intrusive.
Tom was professional, knowledgeable and efficient. I got the quote fast and I look forward to Attic Pros doing the work.
We had Samim come out to our house. He was so kind, fair, and professional, and put me at ease following an exorbitant price gouging experience. I highly recommend Attic Pros and if you can, ask for Samim. You will be happy with the quality of their work as well.
QUESTIONS, ANSWERED
Straight answers to what people actually ask about foam board — the types, its R-value and moisture resistance, and how it compares. Still weighing your options? Our team is happy to help.
Talk to our team — we're here to help.
(800) 543-0382Explore More
Ready when you are
Tell us about your project — R-value, moisture, or thermal bridging — and we'll assess the space, recommend whether foam board is the right fit, and give you a clear, no-pressure estimate.
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