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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4.6 ★★★★★
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tjw
Chelsea, US
★★★★★ 3
Way too narrow
Size: 9.5 Wide, Color: Burgundy Polished Full Grain
I ordered a wide in this shoe, but it was still way too narrow. I had to return them. Otherwise, it looked like a nice quality shoe.
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Reviewed in the United States on February 12, 2026
B
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BetterEveryDay
Houston, US
★★★★★ 5
I usually wear 11.5's, but I buy 1/2 size smaller to accommodate for stretch. Leather relaxes.
Size: 11, Color: Burgundy Polished Full Grain
5 STARS: These shoes are awesome. I keep coming back for more. I have major foot problems, have tried all kinds of shoes, orthotics, and inserts... but believe it or not, these shoes work better than any of that stuff. I wear them daily. I buy lots of them, for home, for church, and I'm getting my first pair of J&M boots today, for winters in Indiana... Brrrr
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Reviewed in the United States on December 18, 2025
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Doc
Cuba, US
★★★★★ 5
Great price great shoe
Size: 12, Color: Burgundy Polished Full Grain
Excellent shoe. Tried the Sebago penny loafer and the sizing was ridiculous. These J and M are sized perfectly. I’ve had them before and they wear like iron. Very comfortable right out of the box.
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Reviewed in the United States on May 23, 2026
R
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roger mendes
Lowell, US
★★★★★ 5
One of the best shoes
Size: 9.5, Color: Black Polished Full Grain
Outstanding. Fashionable, most comfortable and good construction. No sines of use after quite some time. Highly recommended.
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Reviewed in the United States on March 21, 2026
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xyz
Waukegan, US
★★★★★ 4
Quality shoe but with a slight squeak.
Size: 10 Wide, Color: Burgundy Polished Full Grain
Nice shoes with the classic Penny Loafer design. Fit was better than another brand I tried. Only reason not 5 starts is disappointment due to a slight squeak at times when walking.
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Reviewed in the United States on August 11, 2025

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