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FOAMULAR 250 1 in. x 2 ft. x 8 ft. R-5 Tongue and Groove Rigid Foam Board Insulation Sheathing

  • Saves energy and resists moisture with limited lifetime warranty
  • Tongue and groove board edge to reduce gaps and eliminate drafts
  • 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 in a wide choice of sizes, thicknesses and edges with a Lifetime Limited Warranty for the life of the home or building. The products are easy to handle, score, cut and install & no special tools are needed. Products can be used on wood, steel framing or concrete walls. FOAMULAR XPS resists moisture and retains R-value even after exposure to standing water and wet soil. Only XPS foam to be GREENGUARD Gold Certified and the first XPS foam certified by Scientific Certification Systems (SCS) to contain a minimum of 20 percent recycled content.
  • Dimensions: 1 in. x 2 ft. x 8 ft.
  • Application: Exterior Foundation Walls, Underslab, Foundations and Crawlspaces
  • Designed to resist moisture and helps to block mildew
  • Has a higher R-value than wood fiber, plywood or 1/2 in. gypsum board products
  • 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
  • Click here to learn more about Eco Options and Energy Efficiency

Info & Guides

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


Compatible Install Surface
Faced or Unfaced
Insulation Features
Formaldehyde Free
Insulation Location
Insulation R-Value
Insulation Type
Foam Board Insulation
Number of Pieces
Pack Size
Product Weight (lb.)
2.2 lb
Sheathing Size
8 ft. x 1 in. x 24 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 7 reviews
  • 100% recommend this product
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Showing 1-7 of 7 reviews
Very Satisfied
Very Easy to install. will definitely buy this product again. we noticed a difference immedately after installing this in our basement.
  • DIY
  • Recommended
5 people found this helpful
Easy to use - works like a charm
I recently used this to insulate the interior of my basement. It went up easily. In fact, it went up so quickly that insulating the basement was the most satisfying part of the entire basement finishing project. When needed I trimmed with a utility knife before using adhesive to stick these to the cinder block walls. I did not think of my basement as cold before this work, but I noticed a difference immediately - it is now the coziest room in the house. I would use this stuff again in a heartbeat. I spent a great deal of time reviewing the various insulation options before choosing foamular XPS. So glad I made this choice. The combination of ease of use, effective insulation, and ability to use below grade made this exactly what I needed.
  • DIY
  • Recommended
1 person found this helpful
I needed to fill in a misplaced window. I used this product to insulate the outside. Since the outside of the project was inside my garage I asked the employee that was helping me if this product was paintable. I was told it was and used a waterproof primer/paint spray. It was melting the board. It wasn't major but I would recomend some sort of over boarding or paneling if you want to paint for weatherproofing. In all I liked the product's ease of instillation, and was impressed at the insulationing effect for my kitchen.
  • DIY
  • Recommended
1 person found this helpful
Dood Stuff
Does the job. I installed it on the underground walls of the basement. This winter my laser temperature gun showed room temperature on the foam and 5 to 10 degrees lower on adjacent uninsulated wall. I used 2 inch foam board on above ground walls with similar results.
  • DIY
  • Verified Purchase
  • Recommended
Expensive but efficient
I used this to muffle the sound of an inline fan on a false wall and it worked great. it's very easy to work with which is why i pay for it but on the expensive side for insulation.
  • DIY
  • Recommended
3 people found this helpful
this product is awsome
Do you want to save energy, this will do it. Its tough and the r value is very good compared to the other products and easy to install. Thanks home depo for another great item
    • Recommended
    11 people found this helpful
    It may be sold as insulation, but it's the ONLY sheet foam product you want to use for hobby projects! Lightweight and quite strong, it cuts and shapes easily - and without those annoying "sticky balls" that get all over everything when you use "white styrofoam" which is easier to find. This pink foam sheet is the first choice of serious model railroaders and model airplane builders, and even sculptors who do lightweight sculptures!
    • DIY
    • Recommended
    13 people found this helpful
    Showing 1-7 of 7 reviews