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Model #20WE

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FOAMULAR 150 1 in. x 4 ft. x 8 ft. R-5 Scored Square Edge Rigid Foam Board Insulation Sheathing

  • Saves energy and resists moisture with limited lifetime warranty
  • Scored edge easily snaps into smaller boards for best fit
  • Strong, lightweight pink foam panels don't require special tools
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Product Overview

Home with pink outline and Owens Corning logo

A Home is a Fortress

It keeps comfort and safety in - and the other stuff out. Help create the year-round protection every home deserves with proven solutions that work where and when you need them most.

close up of Owens Corning Foamular with water beads

Owens Corning FOAMULAR XPS

FOAMULAR is a rigid insulation board made of extruded polystyrene. XPS for short. Compared to EPS products, FOAMULAR XPS has 25% more insulating power and is 10 times more water resistant.

Cutaway image of a house with Foamular installed in different locations

Choose Above- and Below-Grade Protection

FOAMULAR provides continuous insulating power around the entire home from the foundation to the roofline and all kinds of spaces in between.

man installing fiberglas insulation  over Foamular

Insulating Basement Walls

FOAMULAR is the easy-to-install insulating solution for basement walls. Get added comfort with PINK Fiberglas insulation and finish with drywall board.

man installing Foamular in exterior foundation application

Insulating Foundation Walls

FOAMULAR is ideal for insulating exterior foundation walls. Extremely durable, it can withstand up to 15-25 psi and resists common acid soils and decay.

man installing siding over Foamular

Insulating Under Exterior Siding

FOAMULAR provides a higher R-value per inch than other materials commonly used for exterior wall sheathing.

man installing Foamular fanfold insulation

Also Available in Fanfold

FOAMULAR Fanfold is generally intended for use as a backer board for residing applications and comes in 50-foot sections for a faster install.

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Superior Moisture Resistance

Virtually impervious to moisture. FOAMULAR has up to 10X more resistance to water than EPS insulation.

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Durable, Yet Flexible

A wide range of compressive strengths –up to 100 psi – to handle heavy loads.

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Easy to Cut, Form and Fit

Easy to handle, score, cut and install; no special tools needed.

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Outstanding Insulating Properties

High, stable R-value (5 per inch of product thickness) - more than wood fiber, plywood or 1/2” gypsum board.

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Foamular is certified to meet indoor air quality standards under the stringent GREENGUARD Gold Certification Program.

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Lifetime Guarantee

The only XPS with a limited lifetime warranty that guarantees a minimum 90% of R-value for the life of the product.

FOAMULAR Extruded Polystyrene (XPS) Rigid Foam Insulation offers a comprehensive line of products - choose the strength you need, from 15 to 60 PSI and exceptional moisture resistance. Products provide superior insulating properties; R-value (5- in. of product thickness). The products are easy to handle, score, cut and install and no special tools are needed. Products can be used on wood, steel framing or concrete walls. Owens Corning provides home builders and home buyers with a number of insulation solutions to meet their needs.
  • Closed cell product is equal to moisture resistance
  • Lifetime limited warranty
  • Wide choice of sizes, thicknesses and edges
  • Retains R-value even after exposure to moisture and freeze thaw cycling
  • Click here to shop Loctite foamboard adhesive
  • FOAMULAR 150 and 250 are available in various thicknesses and R-values, the difference is the compressive strength. FOAMULAR 150 has a compressive strength of 15 psi and FOAMULAR 250 is 25 psi
  • FOAMULAR is not rated for STC (sound transmission) and does not have any soundproofing properties. Owens Corning fiberglass batts and rolls are great options for acoustic applications.
  • When using FOAMULAR or any low perm insulation, always verify the moisture vapor flow and dew point characteristics of the wall system.  Please check your local building codes for vapor retarder/barrier information.
  • If being used in an interior construction application, painting the FOAMULAR is not recommended as FOAMULAR cannot be left exposed and will need to be covered by a 15 minute thermal barrier such as drywall.
  • If being used for crafts, acrylic or latex based paints can be used with FOAMULAR products.
  • If you're looking to insulate your garage door, Owens Corning Garage Door Insulation Kit is an easy, fast and affordable way to keep your garage warm in winter and cool in the summer.
  • If you’re looking to ventilate your attic rafters, Owens Corning Raft-R-Mate is a XPS foam vent designed to assure unrestricted airflow from the soffit to the ridge vent.
  • FOAMULAR is available in two edge configurations:
  • Square Edge - designed to fit flush next to adjoining boards
  • Scored Square Edge - comes with 3 factory scores, so that you can take a 4' sheet, break it in two and have two, 2' wide sheets (middle score), or you can break it into three 16" wide pieces by snapping at the left and right score.
  • Click here to shop Loctite foamboard adhesive

Info & Guides

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Cover Area Per Bag (sq. ft.)
384 ft²
Coverage Area (sq. ft.)
32 ft²
Product Length (ft.)
8 ft
Product Thickness (in.)
1 in
Product Width (in.)
48 in


Compatible Install Surface
Faced or Unfaced
Insulation Features
Formaldehyde Free
Insulation Location
Exterior Wall
Insulation R-Value
Insulation Type
Foam Board Insulation
Number of Pieces
Pack Size
Product Weight (lb.)
0.131 lb
Sheathing Size
8 ft. x 1 in. x 48 in.
Sheathing Type

Warranty / Certifications

Warranty Information
Limited Lifetime

Questions & Answers

Typical questions asked about products:

  • Is the product durable?
  • Is the product easy to use?
  • What are the dimensions of the product?

Customer Reviews

  • 4.8
    out of 435 reviews
  • 98% recommend this product
Filter by:
Showing 1-10 of 435 reviews
Great for installing Window AC Units
Our AC went down and we need to upgrade from a 4 ton to a 5 ton system w/ additional duct work/electric costing $7000min here in Central Florida. Bought x5 Window units, and installed with this R-5 Foam Insulating Board. Got the idea at first off Reddit, which brought me here. The smaller 1"x2'x2' panels weren't in stock, so had to get the 8' board instead. Very easy to cut down with a box cutter knife. Sealed up with some window/door flashing tape (which was recommended by the sales associate). As we are in a area that gets lots of bugs and rain, wanted to be sure everything was tight.
    • Recommended
    I had to use this product on an attic re-insultation project that required a new engineered appro...
    I had to use this product on an attic re-insultation project that required a new engineered approach to the solution. The product was a success in its application. It is super easy to use and cut or trim in place, especially for tight quarters. The house was a 1930s cape cod with shallow 2x4 ceiling joists. The detail required building up the 2x4 ceiling joists to provide a cavity depth that accepts 2 layers of R-19 or one layer of R-38, then cap the enitre area of rolled insultation with R-10 rigid foam to provide a minimum R-rating of 48. Additionally, capping the entire area with rigid foam enabled a platform working surface for future attic accessibility and wiring/ventilation/interior roof maintenance. Overall, very impressed with the product.
    • Verified Purchase
    • Recommended
    1 person found this helpful
    Used to make a quilters station on a wall
    Used to make a quilters station on a wall
    • Verified Purchase
    Product does what I needed to. Used as full sheet...
    Product does what I needed to. Used as full sheet to insulate along my basement walls and then frame next to it. This helped reduced install time so I wasn’t cutting them to fit perfectly in between studs. You can feel the difference in temperature and the price was better on my wallet too
    • Verified Purchase
    Did not work as advertised
    I put up Foamular sheets under polycarbonate roofing panels in my gazebo. Figured since the sheets were advertised at able to withstand temperatures of 165 Deg F, they would be fine. Not so. The sheets just buckled and warped and stuck to the polycarbonate. They also shrank in thickness from 1in down to less than 1/2in. The sheets became very brittle and just cracked. The temperature was over 100 Deg F, maybe 110 Deg F, but nowhere near 165 Deg F. Looks like they do not handle being exposed to sunlight - even if under polycarbonate sheets. Have to peel them off - they are stuck to the polycarbonate - in pieces. Also the polycarbonate sheets are ruined. Have to figure out how to maybe sand down the stuck on bits of Foamular.
    Response from OwensCorningJun 3, 2020
    Hello KP, Thanks for sharing your experience. It helped us learn a little bit more about how customers use our products. Please feel free to contact us at 1-800-GET-PINK so we can address your concerns directly. Thank you for your review.

    Thank you!
    Owens Corning
      7 people found this helpful
      I used this to insulate my garage door from the heat of the morning sun. It did that, plus much m...
      I used this to insulate my garage door from the heat of the morning sun. It did that, plus much more. The sound insulation is better than anything I could have expected. I live on a busy four lane road and the difference is DRAMATIC! I can still hear the road noise, but not much. Also I have a neighbor that likes to play load music while working on their car. So loud that the garage door would literally rattle, that is no more. Oh yeah, the garage doesn't heat up as much either. Other things worth mentioning. The sheets were perforated every 12 or 24 inches which saved my life once I realized it was NOT going to fit in my Honda Pilot. I was able to break it down in the parking lot. When I was cutting it to size, it was easy to mark with a pencil and then cut with a utility knife. I found that if I cut firmly and confidently I could cut the sheet and then snap it apart without the need for a second pass. It breaks super cleanly.
        • Recommended
        14 people found this helpful
        Easy to use and insulated my basement ...
        Easy to use and insulated my basement
        • Verified Purchase
        1 person found this helpful
        This was a life saver this winter keeping a hermit...
        This was a life saver this winter keeping a hermit crab tank at the proper temperature.
        • Verified Purchase
        We use these boards to make light weight set for stage performances. They cut and paint easily an...
        We use these boards to make light weight set for stage performances. They cut and paint easily and glue together using the recommended glue and wood skewers to hold them together. The 4 star rating rather than a 5 star was because the shelf was not fully stocked and I had to take a couple culls!
        • Verified Purchase
        • Recommended
        6 people found this helpful
        I used these sheets to build foam blocks as a Christmas present. I cut them on my table saw at a ...
        I used these sheets to build foam blocks as a Christmas present. I cut them on my table saw at a 45 degree angle. They cut very smoothly and the end product was loads of fun on Christmas day and New Year's Eve. I glued the pieces with Gorilla glue and taped them with metal heat duct tape.
        • DIY
        • Verified Purchase
        • Recommended
        1 person found this helpful
        Showing 1-10 of 435 reviews