At a Glance

Coverage Area: 32 (sq ft)

Mold Resistant

Water Resistant

Ask Mylow

Mylow is an AI virtual assistant.

More Information

Is it easy to install?How much R-Value does it have?What is the warranty period?Can I use it in walls?Will this resist moisture?

STYROFOAM Residential Sheathing R- 3.9 , 0.78-in x 4-ft x 8-ft Faced Polystyrene Board Insulation

Name: STYROFOAM Residential Sheathing R- 3.9 , 0.78-in x 4-ft x 8-ft Faced Polystyrene Board Insulation
Brand: STYROFOAM
SKU: 5014009677
Rating: 4.5 (171 reviews)

Shop STYROFOAM

4.5

171

Get Pricing & Availability

Common Thickness (Inches): 0.78

0.55

0.78

Members save more.

Here are some similar items...

Kingspan InsulationR- 2.8 , 0.50-in x 4-ft x 8-ft Unfaced Foam Board Insulation

107

STYROFOAMResidential Sheathing R- 5 , 1-in x 4-ft x 8-ft Faced Polystyrene Board Insulation

170

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

170

Perma "R" ProductsR- 7.8 , 2-in x 4-ft x 8-ft Faced Polystyrene Board Insulation

912

Owens CorningFOAMULAR NGX F-150 R- 7.5 , 1.5-in x 4-ft x 8-ft Unfaced Polystyrene Board Insulation

152

InsulfoamR- 1.88 , 0.5-in x 4-ft x 8-ft Faced Expanded polystyrene Board Insulation

833

Rmax Thermasheath R- 6 , 1-in x 8-ft x 4-ft Faced Polyisocyanurate Board Insulation

R- 2.9 , 0.75-in x 4-ft x 8-ft Faced Polystyrene Board Insulation

695

Kingspan InsulationR- 5 , 1-in x 4-ft x 8-ft Unfaced Foam Board Insulation

166

Perma "R" ProductsR- 7.8 , 2-in x 4-ft x 8-ft Faced Polystyrene Board Insulation

300

R- 3.9 , 1-in x 4-ft x 8-ft Faced Polystyrene Board Insulation

854

Owens CorningFoamular NGX Wall Panel R- 7.5 , 1.4-in x 1.1875-ft x 4-ft Unfaced Polystyrene with Sound Barrier Board Insulation

STYROFOAMResidential Sheathing R- 2.75 , 0.55-in x 4-ft x 8-ft Faced Polystyrene Board Insulation

170

Rmax Thermasheath R- 5 , 0.75-in x 8-ft x 4-ft Faced Polyisocyanurate Board Insulation

Johns ManvilleAP Foil R- 9.3 , 1.5-in x 4.0-ft x 8.0-ft Faced Polyisocyanurate Board Insulation

355

Best Price. Guaranteed

Find a lower price on an exact item? We'll match it. Some exclusions apply.

Price Guarantee

FREE Returns

Return it in store or ship it back for free. Eligibility rules apply.

Return Policy

FREE Shipping

Delivery is on us for orders over $45. Some exclusions apply.

Shipping Details

Styrofoam Brand Residential Sheathing adds up to an investment that will pay for itself in just a few years, and continue to provide value for years to come. Using Residential Sheathing could lead to fewer callbacks resulting in an enhanced reputation for builders. Extruded polystyrene foam insulation like Residential Sheathing is inherently resistant to moisture, which can wreak havoc on other building materials. Moisture can compromise the performance of cavity insulation and damage drywall, wood framing and OSB or plywood sheathing.

STYROFOAM Residential Sheathing is an extruded polystyrene foam board with plastic film facers on both sides providing a long term insulating performance of R-5 per inch sizing
This 0.78-in thick 4ft x 8ft Residential Sheathing has a tongue and groove edge treatment to help boards fit snugly against one another and ensure energy efficiency
Lightweight, making it easy to handle and remains a simple matter to cut to size with a score and a snap
Defends against wind-driven moisture penetrating a wall system, providing an effective layer of protection for wood components and cavity insulation while moderating temperature in the wall cavity
Minimum compressive strength of 15 PSI
New formulation reduces global warming potential (GWP) and greenhouse gas (GHG) emissions - you will get aesthetics, performance and sustainability
Can be placed directly over uninsulated studs using let-in bracing or metal strappings to provide the code-required lateral structural bracing, or as an insulating and weather barrier layer over wood panel sheathings such as OSB or plywood
15 year limited warranty for peace of mind

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

Dimensions
Actual Length (Feet)	8	Common Width (Feet)	4
Actual Thickness (Inches)	0.78	Coverage Area (Sq. Feet)	32
Actual Width (Feet)	4	Package Weight (lbs.)	3.53
Common Length (Feet)	8	R-Value per Inch	5
Common Thickness (Inches)	0.78	Maximum R-Value	3.9

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

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

Warranty
Warranty	15-year limited

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

Miscellaneous
UNSPSC	30141500

Check out the Best Selling Board Insulation on Lowes.com

Review

4.5 out of 5

171 Reviews

88% Recommend this product

Ratings may include incentivized customer reviews.

Read All Reviews

+ 7

What Customers Are Saying

Customers overwhelmingly praise this foam board for its clean, precise cutting with basic tools like utility knives and cordless saws, lightweight installation, and effective thermal and acoustic insulation across diverse applications from garages to trailers. Many highlight its sturdy construction, good R-value, waterproof properties, and ability to conform to uneven surfaces without specialized equipment. Reviewers consistently note its durability and reliability indoors, with a few mentioning it feels slightly thin for outdoor use. A small number report concerns about extreme heat resistance, though most consider it an excellent, dependable choice for insulation and detailed projects.

Customer review summary generated by AI, including incentivized reviews.

171 Customer Reviews

Sort By

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

Was this Review Helpful ?

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

Was this Review Helpful ?

Lowe's lumber is always nice and straight awesome!

Would Recommend

EZ E 69July 13, 2026
Verified Purchaser

Was this Review Helpful ?

31 Questions

Read All Q&A

Sort By

STYROFOAM: Featured Videos

COMPARE PRODUCTS

		Name	Current Item STYROFOAMResidential Sheathing R- 3.9 , 0.78-in x 4-ft x 8-ft Faced Polystyrene Board Insulation
		Ratings	170
		Insulation Type	Polystyrene
		Actual Thickness (Inches)	0.78
		Common Thickness (Inches)	0.78
R- 1.5-in x 4-ft x 8-ft Expanded polystyrene	Perma "R" ProductsR- 7.8 , 2-in x 4-ft x 8-ft Faced Polystyrene Board Insulation	Perma "R" ProductsR- 7.8 , 2-in x 4-ft x 8-ft Faced Polystyrene Board Insulation	InsulfoamGarage Door Insulation Kit R- 4.8 , 1.25-in x 1.6875-ft x 8-ft Faced Polystyrene Board Insulation	Owens CorningFOAMULAR NGX F-150 R- 5 , 1-in x 4-ft x 8-ft Unfaced Polystyrene Board Insulation	Rmax Thermasheath R- 6 , 1-in x 8-ft x 4-ft Faced Polyisocyanurate Board Insulation	Rmax Thermasheath R- 5 , 0.75-in x 8-ft x 4-ft Faced Polyisocyanurate Board Insulation	Kingspan InsulationQ250 Fanfold Siding Underlayment R- 0.9 , 0.2-in x 4-ft x 48-ft Faced Foam Board Insulation	Owens Corning703 Series R- 8.7 , 2-in x 2-ft x 4-ft Faced Fiberglass with Sound Barrier Board Insulation
787	912	300	1028	152	6	3	39	4
Expanded polystyrene	Polystyrene	Polystyrene	Polystyrene	Polystyrene	Polyisocyanurate	Polyisocyanurate	Foam	Fiberglass
1.4375	2	2	1.25	1	1	0.75	0.2	2
1.5	2	2	1.25	1	1	0.75	0.2	2