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Attic Pros
Bay Area Foam Board Insulation · Licensed · 13+ Years

Foam Board Insulation in the San Francisco Bay Area

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.

Free assessmentLicensed (CSLB #1022608)High R per inch13+ years experience
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Free on-site estimate · No pressure · We come to you

Rigid foam board insulation being fitted and sealed

The High-R,
Moisture-Tough Panel

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.

  • High R-value per inch — more in less space
  • Resists moisture — good below grade
  • Continuous coverage cuts thermal bridging
  • Rigid — durable and stable over time
  • Great for rim joists & foundation walls
  • Pairs well with cavity insulation

EPS, XPS &
Polyiso

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.

EPS (Expanded Polystyrene)

The white bead-board panel — the most economical of the three.

Pros
  • Most budget-friendly
  • Holds its R-value over time
  • Works below grade with drainage
Trade-offs
  • Lowest R per inch of the three
  • Absorbs more moisture than XPS

XPS (Extruded Polystyrene)

The dense colored board (often pink/blue) built for moisture.

Pros
  • Strong moisture resistance
  • Solid R per inch
  • Durable for below-grade walls
Trade-offs
  • Pricier than EPS
  • R can ease slightly over decades

Polyiso (Polyisocyanurate)

The foil-faced board with the highest R of the three.

Pros
  • Highest R-value per inch
  • Foil facing adds a radiant/vapor layer
  • Great for walls & roofs above grade
Trade-offs
  • R drops in very cold temperatures
  • Not the pick for below grade
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When Foam Board
Is the Right Choice

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.

Not sure foam board is the right material — or whether batt, cellulose, or rockwool would serve better? Book a free assessment and we'll give you an honest recommendation for your space.

Our Foam Board Insulation Installation Process

Foam board only performs when the panels are cut tight, sealed continuous, and covered to code. Here's how we handle every install.

Free assessment

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.

Select board type & thickness

We recommend EPS, XPS, or polyiso and the right thickness to hit your R-value and moisture target for the location.

Prep & remove if needed

If existing insulation is old, wet, or contaminated, we remove and haul it away so the foam board seats on a clean, sound surface.

Cut, fit & seal

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.

Verify & clean up

We confirm full, gap-free coverage and proper sealing, clean up completely, and walk you through the finished job.

Free assessmentLicensed (CSLB #1022608)Sealed, code-compliant install
Attic Pros insulation team

The Bay Area's Trusted
Insulation Installers

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.

  • Licensed contractor (CSLB Lic. #1022608)
  • SPCB-registered for pest-related work (Co. Reg. #9901)
  • Diamond Certified & Angi Super Service Award winner
  • Independently reviewed — verified Google ratings
  • Free, no-obligation on-site assessment
  • Local team with 13+ years in Bay Area homes

Trusted by Bay Area Homeowners

4.8
★★★★★
Based on 1,900+ verified Google reviewstrusted for insulation & home services across the Bay Area
Google Review
★★★★★

Tom was a great help Thanks again tom for make sure this all goes smoothly G

amos jack
recently
Google Review
★★★★★

Attic Pros recently replaced my old insulation with new insulation. I called them back today 3 weeks later to check on the Rat traps they placed in the Attic as I experienced an unusual odor coming from the air vents throughout the house. Jose of Attic Pros responded and was a very upbeat chearful person who explained what he was going to do prior to going into the Attic to check on the Rat Traps. Fortunately the traps were still set with no activity. Jose took photos ( see attached) while he was in the Attic which showed no activity. I later found that the odor was a filter in the hvac systrem which had debris which causec the odor. Jose completed the inspection by walking around the house and inspecting the outside vents which I appreciated. All the Attic Pro employees which I have come into contact with are Professional, friend;y an do a thouough job completing whatever jobs in their field are requested.

DAVID BERTI
recently
Google Review
★★★★★

These guys are great! Wais Amiry came out to take a look at my attic for rat infestation, they showed up fast and they were super professional. Would use them again!

Carmen Garcia-Jones
recently
Google Review
★★★★★

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.

Colleen Burns
3 weeks ago
Google Review
★★★★★

Tom is a professional and did a very detailed inspection, also gave additional details to prevent in future infestation.

ajit rathi
3 weeks ago
Google Review
★★★★★

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.

Will Le
3 weeks ago

QUESTIONS, ANSWERED

Frequently Asked Questions

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.

Still have questions?

Talk to our team — we're here to help.

(800) 543-0382
It's rigid panel insulation — stiff sheets of plastic foam that are cut, fit, and sealed into place rather than stuffed into a cavity like a batt. It's valued for a high R-value in a thin profile, moisture resistance, and continuous coverage that cuts heat loss through framing.
They're the three generic types of foam board. EPS (expanded polystyrene) is the economical white bead-board; XPS (extruded polystyrene) is the denser colored board built for moisture; and polyiso (polyisocyanurate) is the foil-faced board with the highest R-value per inch. Each trades off R-value, moisture resistance, and cost differently, and we match the right one to your job.
It's among the highest per inch of common insulations. Roughly speaking, EPS is the lowest of the three, XPS sits in the middle, and polyiso is the highest per inch — so foam board delivers more R in a thinner layer than fiberglass or cellulose. Your total R-value depends on the type and thickness installed, which we size to your target.
Yes — that's one of its biggest advantages. XPS and polyiso in particular resist moisture well, which is why rigid foam is a strong choice for foundation walls, crawl spaces, and other damp or below-grade spots where fiber insulation would sag and lose performance.
Foam board is a rigid, continuous layer with a high R per inch that cuts thermal bridging through framing. Batt and blown-in are cavity insulations that fit or fill between studs and joists and are more economical for open areas. Foam board wins in tight, damp, or exposed assemblies; cavity insulation wins for filling open attic floors and stud bays. See our batt, cellulose, and rockwool pages to compare.
Common spots include rim and band joists, foundation and crawl-space walls, under slabs, exterior wall sheathing, and cathedral ceilings or roofs — anywhere continuous coverage, a high R in a thin profile, or moisture resistance matters most.
In living spaces, yes. Rigid foam is a plastic-foam product, so building codes generally require it to be covered with a code-approved thermal or ignition barrier (such as drywall) where it's exposed. We handle that to code as part of the installation.
Absolutely — it's often paired rather than used alone. A common approach is continuous foam board over the framing plus a cavity insulation like batt or blown-in inside, combining foam board's thermal-bridge control with the cavity fill's economy. We'll recommend the right combination for your home.
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Get Your Free Insulation Estimate

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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