SKU: 59277810533

Owens Corning FOAMULAR R-1 Extruded Polystyrene Fanfold Underlayment Insulation, 1/4 in. x 4 ft. x 50 ft., Square Edge

Sale price$63.49 Regular price$70.55
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Description

Owens Corning FOAMULAR R-1 Extruded Polystyrene Fanfold Underlayment Insulation, 1/4 in. x 4 ft. x 50 ft., Square EdgeFOAMULAR R 1 1 4 in. Fanfold XPS Underlayment Lightweight, moisture resistant XPS fanfold underlayment designed for re siding and sheathing applications. The 1 4 in. thick, 4 ft. x 50 ft. board delivers R 1 thermal performance and folds for fast coverage and easy handling. Key Features: Moisture Resistant XPS: Retains R value even after exposure to water. Easy Handling & Install: Fanfold design cuts and scores simply; no special tools required. Re

FOAMULAR R-1 1/4 in. Fanfold XPS Underlayment

Lightweight, moisture-resistant XPS fanfold underlayment designed for re-siding and sheathing applications. The 1/4 in. thick, 4 ft. x 50 ft. board delivers R-1 thermal performance and folds for fast coverage and easy handling.


Key Features:

  • Moisture-Resistant XPS: Retains R-value even after exposure to water.
  • Easy Handling & Install: Fanfold design cuts and scores simply; no special tools required.
  • Re-Siding Ready: Ideal as underlayment/sheathing for re-siding projects.
  • Durable Performance: Strong, lightweight board with long-term thermal retention.
  • Low-Emitting & Certified: GREENGUARD certified; formaldehyde-free blowing agent with reduced GWP.

Please check the Product Data Sheet Here


Specifications Table:

Specification Details
Insulation Type Foam Board Insulation (XPS)
Insulation R-Value R-1
Thickness 0.25 in (1/4 in.)
Width 48 in. (4 ft.)
Length 50 ft.
Coverage Area 200 sq. ft.
Edge Profile Square Edge
Faced or Unfaced Unfaced
Compatible Install Surface Concrete, Plywood, Wood
Interior/Exterior Interior; commonly used for re-siding underlayment
Number of Pieces 1
Pack Size 1
Product Weight 13.2 lb
Sheathing Type XPS
Insulation Features Formaldehyde Free; GREENGUARD Certified; Low water absorption; High R-value retention
Warranty Limited Lifetime

Frequently Asked Questions (FAQ):

Q: What are the dimensions and coverage?
A: Each fanfold measures 1/4 in. thick, 4 ft. wide, and 50 ft. long, covering 200 sq. ft.


Q: Where can I use this product?
A: Commonly used as re-siding underlayment or insulating sheathing over wood, plywood, or concrete surfaces.


Q: Is it faced?
A: No, this product is unfaced XPS foam board.


Q: How moisture resistant is it?
A: XPS construction provides low water absorption to help maintain R-value in wet conditions.


Q: Do I need special tools to install?
A: No. It scores, snaps, and cuts easily with standard utility knives.


Streamlined Sheathing with a Sleek, Modern Edge

This fanfold insulation creates a crisp, continuous plane behind new siding, elevating exteriors with a polished, tailored finish. I love its subtle flexibility—the panels fold effortlessly to glide across large walls, minimizing seams and visual clutter. Pair it with fiber-cement or cedar cladding to achieve a refined envelope and improved comfort. It’s a quiet luxury—performance you feel, with a look that’s impeccably composed.


Upgrade your re-siding project with FOAMULAR fanfold insulation for faster installs, lasting R-value, and a cleaner finish—add it to your cart today.

Installation

Shipping Notes
  • Free Standard Shipping on $100+ Orders to the USA.
  • Except Preorder products are shipped in 48 hours.
  • Delivery to the USA:
  1. Standard Shipping : 3-10 business days
  • If time is of the essence, please consider selecting expedited delivery for faster service.
Exchange/Return Notes
  • We offer a 30-day return/exchange service after receiving.
  • Final sale items are not eligible for returns or exchanges.
  • To process your return/exchange, please contact us at [email protected]
  • Please click here for more details>>> Return & Exchange Policy
SKU: 59277810533

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4.2 ★★★★★
Based on 1177 reviews
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A
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Ashley M.
San Leandro, US
★★★★★ 5
Boyfriend loves it for golf ⛳️! Super comfy, cooling, soft material
Size: X-Large, Color: Grey Stripe
Boyfriend wanted me to leave a review to let all the people that may want to buy this.. that they need to right away! I am a witness to how soft, smooth, slick, and sexy this shirt is! Looks good on him, and feels good too! It is some seriously great material a shirt, versatile, and very nice fit. He is 180 lbs 6’2 and uses it when he goes golfing. He had me order it in a few other colors as well! Washing it has been a breeze for us as well.
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Reviewed in the United States on May 13, 2026
A
Verified Purchase
Amazon Customer
Lexington, US
★★★★★ 5
comfort!
Size: Large, Color: White Stripe
Fits nice, moisture wicking, feels nice and cool.
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Reviewed in the United States on April 17, 2026
E
Verified Purchase
Eric
Massapequa, US
★★★★★ 5
Great Shirt for the $$$
Size: XX-Large, Color: Green
I wasn't expecting much for the price, but I liked the look and the color so I ordered it. After receiving it I can tell you with confidence this is a high quality polo and the feel is amazing. Very comfortable to wear all day, wicks moisture very well, and looks like an expensive shirt you'd expect to pay 3x as much for. Very please with this shirt.
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Reviewed in the United States on February 9, 2026
E
Verified Purchase
E
Birmingham, US
★★★★★ 5
Top quality
Size: Medium, Color: #White
Lightweight, breathable, super nice for warm weather! Easy wash Definitely buying more !
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Reviewed in the United States on May 30, 2026
M
Verified Purchase
Majestic
Battle Creek, US
★★★★★ 3
Although it was a quality made shirt, not happy with the fit and style.
Size: X-Large, Color: Grey Stripe
Order this in an XL size for my son-in-law for Xmas. He isn't overally big, but likes the XL size for a little more roominess. After Xmas he tried it on. Although it was a quality made shirt, he wasn't happy with the fit and style. A no hassle return.
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Reviewed in the United States on February 23, 2026

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