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FOAMULAR 1/2 in. x 4 ft. x 8 ft. R-3 Square Edge Rigid Foam Board Insulation Sheathing

  • Saves energy and resists moisture with limited lifetime warranty
  • Blocks mildew, corrosion and rot; easy to cut and install
  • 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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Sustainable

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: 1/2 in. x 4 ft. x 8 ft.
  • Application: Exterior above grade walls, underneath vinyl siding / claddings
  • Closed cell rigid foam board, 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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FOAMULAR 1/2 in. x 4 ft. x 8 ft. R-3 Square Edge Rigid Foam Board Insulation Sheathing

Compare Similar Foam Board Insulation

FP Ultra Lite 1 in. x 2 ft. x 4 ft. Stucco Grey Foundation PanelTop Rated24 in. x 1 in. x 48 in. R5 Radiant Acoustic Insulation Kit - STC 19 (5-Piece)
current product
FOAMULAR 1/2 in. x 4 ft. x 8 ft. R-3 Square Edge Rigid Foam Board Insulation Sheathing
BrandSTYRO IndustriesSilveRboardOwens Corning
NameFP Ultra Lite 1 in. x 2 ft. x 4 ft. Stucco Grey Foundation Panel24 in. x 1 in. x 48 in. R5 Radiant Acoustic Insulation Kit - STC 19 (5-Piece)FOAMULAR 1/2 in. x 4 ft. x 8 ft. R-3 Square Edge Rigid Foam Board Insulation Sheathing
Price
$2295
$3720
/package
Ratings
(39)
(240)
(163)
Product Thickness (in.)1 in1 in0.5 in
Insulation LocationExterior Wall Foundation2x4 Wall,2x6 Wall,2x8 Wall,Attic,Basement,Ceiling Insulation,Exterior Sheathing,Garage,Metal Building,Re-SidingExterior Sheathing
Insulation R-ValueR5R5R3
Insulation FeaturesMold Resistant,Paintable,Water ResistantFormaldehyde Free,Vapor RetardantFormaldehyde Free
Sheathing TypeXPSEPSXPS
Compatible Install SurfaceCement,Concrete,Existing InsulationCement,Concrete,Existing Drywall,Existing Insulation,PlywoodPlywood,Wood
Faced or UnfacedFacedFacedFaced
View ProductView ProductView Product

Specifications

Dimensions

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

Details

Compatible Install Surface
Plywood,Wood
Faced or Unfaced
Faced
Insulation Features
Formaldehyde Free
Insulation Location
Exterior Sheathing
Insulation R-Value
R3
Insulation Type
Foam Board Insulation
Interior/Exterior
Exterior
Number of Pieces
1
Pack Size
4
Product Weight (lb.)
2.7 lb
Sheathing Size
8 ft. x 0.5 in. x 48 in.
Sheathing Type
XPS

Warranty / Certifications

Warranty Information
Limited Lifetime

Questions & Answers

Typical questions asked about products:

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

Customer Reviews

  • 4.8
    out of 163 reviews
  • 100% recommend this product
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Showing 1-10 of 163 reviews
I use this to carve short term use signs on my CNC machine! Great for cheap signs! Carves real we...
I use this to carve short term use signs on my CNC machine! Great for cheap signs! Carves real well, just use the right bit and speeds to prevent "fuzzies". Also useful for beginner CNCers who are just learning their machine.
by Dave
  • Verified Purchase
  • Recommended Product
We use this in shipping "High End" music, Sports memorabilia and fine art. I am "KNOWN" as havin...
We use this in shipping "High End" music, Sports memorabilia and fine art. I am "KNOWN" as having a "PERFECT" record THANKS to you guys at Owens Corning
by Galileancowboy
  • Verified Purchase
  • Recommended Product
1 person found this helpful
Great product. Easy to install. Would definitely recommend this product.
Great product. Easy to install. Would definitely recommend this product.
by Barbara
  • Verified Purchase
  • Recommended Product
It's foam board, easy to cut, easy to use.
It's foam board, easy to cut, easy to use.
by Jmac
  • Verified Purchase
  • Recommended Product
6 people found this helpful
I bought this to cut up into little headers to block the air coming from the soffit vents in the ...
I bought this to cut up into little headers to block the air coming from the soffit vents in the attic I was finishing. It worked well for the purpose and after being foamed in, no air was coming through to windwash the fiberglass batts I put in the slopes.
by Fatty
  • Verified Purchase
  • Recommended Product
2 people found this helpful
Used for birthday party decorations
I bought 3 of these sheets for my sons first birthday party! It was a jungle/safari themed and I sent them out to my friends bf to paint some animals. He did a mural/background typed n I used it as a backdrop for the chocolate fountain table. The other two were giraffes that I put on bushes since the party was on our backyard. This year doing a Mickey Mouse themed n I'm going to buy some of these sheets!!
by Princess510
  • DIY
  • Recommended Product
48 people found this helpful
Works very well around the hole house.. did not use...
Works very well around the hole house.. did not use fiberglass at all.. house stays where I set it
by NICK
  • Verified Purchase
Rating provided by a verified purchaser...
Rating provided by a verified purchaser
by HomeDepotCustomer
  • Verified Purchase
Are use these sheets to design light weight decorations for...
Are use these sheets to design light weight decorations for professional stage designs. I cut it with a hot knife and it’s like slicing butter!
by DesignsWithPromise
  • Verified Purchase
Our company uses this product for expansion material on bridge work. The material is not super ri...
Our company uses this product for expansion material on bridge work. The material is not super rigid like other brands, which helps during installation.
by Smashedyerthumb
  • Verified Purchase
  • Recommended Product
Showing 1-10 of 163 reviews