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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4.3 ★★★★★
Based on 11 reviews
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Mike c
Alexandria, US
★★★★★ 5
My 2 German shepherds love these good quality last a good bit
Size: Large (Pack of 1)
I buy these for my 2 German shepherds. My male is a heavy chewer and he will spend time with this everyday until he starts to wear it down or makes it into a makeshift shank and I replace it Last about 3-4 months for aggressive chewers. Highly recommend (keeps them from chewing my stuff)
WAS THIS REVIEW HELPFUL?YesReportShare
Reviewed in the United States on May 1, 2026
R
Verified Purchase
Reviewer 22
Carnegie, US
★★★★★ 5
The best bone you can get for pitbulls!
Size: Large (Pack of 1)
Can I give these more than five stars? Please?? They truly deserve more than that! I have bought these bones for the last 2 years for my pitbull mix, who is a very aggressive chewer. Her favorite thing to do is just lay and chew. These bones last FOREVER! She can lay there and chew all day long and they will last her MONTHS! It’s honestly amazing! These are the best bones we’ve ever given her and they are the only ones we’ll buy her! Not only do they last forever, they’re safe and natural too! Best product ever!
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Reviewed in the United States on January 10, 2026
D
Verified Purchase
Dee
Draper, US
★★★★★ 4
Great for aggressive chewers, but small mess
Size: Large (Pack of 1), Size: Large (Pack of 1)
He took it right away! It’s a great size. We’ll see how it holds up ONE MONTH UPDATE: (photo included) He loves it still! Still a bit messy but holding up great and he’s a aggressive chewer 1 WEEK UPDATE (photo update included) The bone is great. He loves it and it’s been holding up great. Our 8 month puppy is a super chewer and 60 lbs. the bone has signs of wear but nothing crazy. I went from 5 stars to 4 stars because whenever he chews the bone, the small tiny pieces of bone/wood go everywhere and they’re sticky/hard and make kind of a mess. But still would get this bone again and highly recommend
WAS THIS REVIEW HELPFUL?YesReportShare
Reviewed in the United States on December 16, 2025
H
Verified Purchase
hellothere
Cuba, US
★★★★★ 5
Dog loves these
Size: X-Small (Pack of 1)
These are the best chew toys. They are reasonably priced and last a long while. Fast shipping.
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Reviewed in the United States on March 8, 2026
V
Verified Purchase
Vanessa
Whiting, US
★★★★★ 5
Made for aggressive chewers
Size: Small (Pack of 1)
My aggressive chewers are obsessed. This is one of the only chew toys that actually lasts for them. Always have to buy 2 so they each have their own
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Reviewed in the United States on February 28, 2026

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