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
Denis from Attic Pros was very thorough and does a great job. He is thoughtful, patient and a good listener to all my concerns. Our home is peaceful now that we don’t have any rodents! I recommend him highly.
Tom is a professional and did a very detailed inspection, also gave additional details to prevent in future infestation.
My wife and I found mice droppings in our kitchen cabinet. We reached out to Attic Pros and was connected with Tom. He was very professional and thorough with his inspection. We went through our crawl space and attic. Gave us a full rundown of issues/problems we may be experiencing now and potentially in the future. Thanks for your expertise and quick follow up with the quote and service Tom.
These guys are awesome. Super clear comms to schedule, then received an extremely thorough consultation. We eventually decided to go with them as other shops in the area didn't communicate as well as Attic Pros.
Tom from Attic Pros was great to work with! He was friendly, professional, and thorough during the inspection. He clearly explained everything he found and answered all of my questions. The whole process was straightforward. Thank you, Tom!
Finding out we had a rodent infestation for the first time was incredibly stressful, but Attic Pros made the entire process so much easier! Jeremy was very knowledgeable when help preparing the estimate and the work that needed to be done. Their team that came to perform the work—Nico Otten, Juan Rodriguez, and Antonio Lopez—were amazing from start to finish. Communication was fantastic right from the beginning. The crew was super fast, highly efficient, and left everything very clean after sanitizing our attic, crawl space, and garage. They definitely gave us total peace of mind. They were also able to finish in one day!!
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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