At a Glance

Coverage Area: 32 (sq ft)

Mold Resistant

Water Resistant

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STYROFOAM Unsheathed R- 10 , 2-in x 4-ft x 8-ft Unfaced Polystyrene Board Insulation

Name: STYROFOAM Unsheathed R- 10 , 2-in x 4-ft x 8-ft Unfaced Polystyrene Board Insulation
Brand: STYROFOAM
SKU: 5014009661
Rating: 4.5 (174 reviews)

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4.5

174

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Common Thickness (Inches): 2

0.55

0.78

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DuPont Styrofoam Brand Square Edge Extruded Polystyrene (XPS) Foam Insulation is an extruded polystyrene foam (XPS) insulation board that provides continuous insulation over steel stud or wood framing, in masonry unit cavity walls, and meets the needs of the commercial foundation and building floor slab needs. It can also be used for attics, foundations/slabs and craw spaces in residential applications.

STYROFOAM Square Edge is a Type IV extruded polystyrene foam insulation designed for use when a higher-compressive strength product is needed, still providing a long term insulating performance of R-5 per inch
The 4ft x 8ft boards of 2-in thickness are designed to ensure energy efficiency and minimize on-site cutting and waste
Easy to handle, cut using a utility knife or serrated blade, and install to commonly used widths
Are resistant to degradation from soil components and will retain insulating performance characteristics after prolonged exposure to moisture - will not corrode, rot or support mold growth
Have a minimum compressive strength of 25 psi
New formulation reduces global warming potential (GWP) and greenhouse gas (GHG) emissions - you will get aesthetics, performance and sustainability
Can be used in a number of applications like sheathing, foundation walls, masonry cavity walls, attics, crawl spaces, and more
50 year limited warranty for peace of mind

General
Compression Strength (PSI)	15	Paintable	Yes
Package Quantity	1	Insulation Type	Polystyrene
Edge Profile	Square Edge	Series Name	Unsheathed
Use Location	Indoor/Outdoor

Dimensions
Common Length (Feet)	8	Package Weight (lbs.)	9.06
Actual Thickness (Inches)	2	Coverage Area (Sq. Feet)	32
Actual Width (Feet)	4	Actual Length (Feet)	8
Common Thickness (Inches)	2	R-Value per Inch	5
Common Width (Feet)	4	Maximum R-Value	10

Features
Fire Resistant	No	Vapor Retardant	Yes
Mold Resistant	Yes	Formaldehyde Free	Yes
Sound Barrier	No	Facing Material	Unfaced
Water Resistant	Yes	Pre-Cut	No
Sound Insulation	No

Certifications
CA Residents: Prop 65 Warning(s)	No	GREENGUARD Gold Certified	No
ENERGY STAR Certified	Yes	Fire Rating	Class A

Warranty
Warranty	50-year limited

Compatibility
Fits 2 x 4 Walls	Yes	For Use in Doors	No
Fits 2 x 6 Walls	Yes	For Use in Floors	Yes
For Use on Wood	Yes	For Use in Garage Doors	No
For Use on Glass	No	For Use on Metal	Yes
For Use in Basements	Yes	For Use in Masonry	Yes
For Use in Attics	Yes	For Use on Plastic	Yes
For Use on Insulation	Yes	For Use in Plumbing	No
For Use in Crawlspaces	Yes	For Use in Walls	Yes
For Use in Ceilings	Yes	For Use in Vents	No
For Use in Electrical	No	For Use in Windows	No
For Use in Duct	No

Miscellaneous
UNSPSC	30141500

Check out the Best Selling Board Insulation on Lowes.com

Review

4.5 out of 5

174 Reviews

88% Recommend this product

Ratings may include incentivized customer reviews.

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+ 7

What Customers Are Saying

Customers overwhelmingly praise the foam board for exceptional ease of use, durability, and insulation performance. Most highlight how cleanly it cuts with a sharp utility knife and its lightweight, versatile nature for DIY projects and model building. Reviewers consistently commend its waterproof coating, air-tight properties, and effective thermal efficiency in garages, attics, and trailers. Many appreciate its rigidity and structural integrity under pressure. Beyond insulation, customers creatively use it for photo backdrops, stage props, and pet shelters. A few mention concerns about thickness for outdoor use or pricing, though these remain isolated. Overall, most find it an excellent, user-friendly solution.

Customer review summary generated by AI, including incentivized reviews.

174 Customer Reviews

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Foam to Insulate Garage Doors

Would Recommend

I purchased the foam to cut into sections and fit it in my garage doors for insulation. It has a rating of R5. I was able to wedge it in there and not use any glue or tape. So far it seems to be cooling it a bit.

PistolPeteSeptember 9, 2026
From Residential Sheathing R- 5 , 1-in x 4-ft x 8-ft Faced Polystyrene Board Insulation Verified Purchaser

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Perfect for cutting full sheets of plywood

Would Recommend

I bought this for cutting full sheets of plywood with a festool track saw, works perfect.

Liv Tradition CarpentrySeptember 3, 2026
From Residential Sheathing R- 5 , 1-in x 4-ft x 8-ft Faced Polystyrene Board Insulation Verified Purchaser

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Very disappointed

I paid $70 for home delivery and I see the product came damaged. I'm so disappointed.

SunnyJuly 26, 2026
From Residential Sheathing R- 5 , 1-in x 4-ft x 8-ft Faced Polystyrene Board Insulation

https://photos-us.bazaarvoice.com/photo/2/cGhvdG86bG93ZXM/2691c260-624a-54f4-88f6-ed209c96d069

https://photos-us.bazaarvoice.com/photo/2/cGhvdG86bG93ZXM/58a19a4c-8000-51c0-a463-d63a49b09496

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You can get better material to use other than this

The material is rigid and breaks really easy. After cutting it to the length you need, you have lots of small particles of foam flaking off and making a mess.

DonkJuly 17, 2026
From Residential Sheathing R- 2.75 , 0.55-in x 4-ft x 8-ft Faced Polystyrene Board Insulation Verified Purchaser

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COMPARE PRODUCTS

		Name	Current Item STYROFOAMUnsheathed R- 10 , 2-in x 4-ft x 8-ft Unfaced Polystyrene Board Insulation
		Ratings	173
		Water Resistant
		Maximum R-Value	10
		Fire Resistant
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