Model # 754404

Internet #100572981

Store SKU #754404

R-Matte Rmax Plus-3 1/2 in. x 4 ft. x 8 ft. R-3.2 Polyisocyanurate Rigid Foam Insulation Board


Rmax Plus-3 1/2 in. x 4 ft. x 8 ft. R-3.2 Polyisocyanurate Rigid Foam Insulation Board

  • Polyiso foam bonded to reinforced aluminum foil facers
  • Ideal for do-it-yourself applications to add insulation value
  • ENERGY STAR approved
$1225 /each
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Frequently Bought Together

Product Overview

R-Matte Plus-3/Thermasheath-3 is rigid foam plastic thermal insulation board. It's made of environmentally sound, closed cell, polyisocyanurate foam bonded to a durable white-matte (non-glare) aluminum facer and a reflective reinforced aluminum facer. This product is suitable for use in wall sheathing applications in new residential, commercial and agricultural buildings and for thermal retrofit construction to existing buildings. This Energy Star qualified Rmatte Plus-3/Thermasheath-3 provides R3.2 with dimensions of .5 in. x 4 ft. x 8 ft. This product is designed for exterior and interior, non-structural uses.

  • Rmax Polyiso sheathing offers the GREATEST R-value per inch currently available in a rigid foam board.
  • R-Matte plus-3/Thermasheath-3 is applied to the exterior or interior face of wood or metal studs to cover all studs, sills, plates and header constructions, thereby providing insulation over areas not normally covered by insulation products
  • Superior resistance to moisture and vapor in above grade applications
  • Polyiso rigid foam board offers superior fire protection properties compared to any other rigid foam board insulation
  • Energy Star qualified to meet or exceed federal guidelines for energy efficiency for year-round energy and money savings
  • When taped and flashed, the Rmax Polyiso board greatly reduces air infiltration and prevents thermal bridging caused by heat and cold transmission through studs
  • Lightweight and easily cut to size

Info & Guides

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Product Depth (in.)
Product Height (in.)
Product Length (ft.)
8 ft
Product Thickness (in.)
.5 in
Product Width (in.)


Insulation Application Type
2x4 Walls,2x6 Walls,Attics,Basements,Ceilings,Crawlspaces,Exterior Sheathing,Garage,Re-Siding
Insulation R-Value
Insulation Type
Product Weight (lb.)
Sheathing Type

Warranty / Certifications

Warranty Information
Standard Warranty

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Customer Questions & Answers

Something wrong

I believe you got the thickness wrong on your page, its only 1/2 inch thick in the specs
Asked by: lemmings88
The product name is Plus-3 which is 1/2 inch thick. It is NOT 3-1/2inches thick.
Answered by: rbv4ik
Date published: 2017-08-10

Is this reflective on one side?

Watched youtube. Considering using inside window to reflect heat. Would rather use Renshade, a reflective perforated material but they don't sell it in U.S.
Asked by: Kathleen
Both sides are aluminum coated; one side IS reflective. I'm re-doing a room and put a couple of these in the window until window treatments go back up. It's my Florida room which always gets warmer than rest of house. Though I got these panels for wall insulation, it does help keep the heat out when put against a window. I'm only using 1/2" (because of the wall" but in front of a window you can get thicker which will have better effect. If you get it, I used a serrated kitchen knife to cut it, nice and clean. A razor makes a mess! (I also posted a review with some pics if you want to look)
Answered by: DreamBuild
Date published: 2017-07-01

Would this be the best way to insulate a van to live in? For a little sound proofing & insulation?

2012 Ford transit connect
Asked by: Jasmine
Sure, if you like being roasted in flames like the buildings recently in London and Dubai. To fireproof it you need to put wallboard toward the living side on top of it. That's going to add weight.
Answered by: Fire
Date published: 2017-08-10

I have a metal carport, could this be used on underside to prevent condensation on inside?

What would be good to fasten it up with?
Asked by: RCW
Tough as Nails adhesive
Answered by: reginald
Date published: 2017-06-09
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Customer Reviews

Rmax Plus-3 1/2 in. x 4 ft. x 8 ft. R-3.2 Polyisocyanurate Rigid Foam Insulation Board is rated 3.9 out of 5 by 21.
Rated 5 out of 5 by from Garage Door insulation I used this product as a garage door insulation. Installed it on each door panel cut to fit with the foil side facing outward. Must install it on some type of standoff, I used 1 inch pink foam board strips I cut and glued to the door panels, then put this over them leaving an air gap between the foil side of the R-Max panel and the door panel. What a huge difference this makes in the temps inside the garage. My garage door faces south-southeast so it gets very hot and makes the garage hot too. Not anymore. Great product and easy to work with. I added a bubble radiant barrier to the inside as well to keep heat in in the winter too.
Date published: 2011-06-20
Rated 4 out of 5 by from Helped quite a bit in keeping the room insulated, the room is much cooler now. Helped quite a bit in keeping the room insulated, the room is much cooler now.
Date published: 2017-08-01
Rated 5 out of 5 by from Insulation Board Did exactly what I needed. Good price too. Will recommend to others.
Date published: 2017-04-12
Rated 5 out of 5 by from Good product Reading reviews of others' problems with this product, I wanted to go with GAF. Unfortunately it was not available and I had a time constraint and couldn't wait; I got the Rmax. Don't use a razor, you'll make a mess, doesn't cut well at all with razor. Can't score and snap either. Looked for alternatives; hand saw didn't work (some have said a circular saw worked - didn't try it), sharpened putty knife etc. didn't work. Nothing worked well till I tried a 9" serrated kitchen knife. Works like a charm! Clean cuts, very little mess Also, Rmax must have listened to quality complaints because I had no voids. They were square with consistent thickness. R value of 3.2 for 1/2", not bad at all. This also works well laid in front of a window. I helped cut down the heat till I could put window treatments back up. This product worked well for me, easy to work with, stayed flat, quality was good. Product is made in U.S.A. so shouldn't have to worry about toxic foreign products.
Date published: 2015-07-23
Rated 1 out of 5 by from Miserable Quality Control For some reason, Home Depot and the other big box store both switched from Dow Super Tuff R to this product. I've used Super Tuff R for 5 years (probably 600+ sheets per year) and found it to be of superior quality. After the switch to this new product, I spent 15 minutes sorting through the stack of 30+ sheets of this new product (R Matte Plus 3) and could only find 6 sheets that didn't have 10% or more the foil facing loose or peeling off the shiny side. In cut outs, pea-sized voids in the foam were common and I twice ran into silver dollar-sized voids where the foam was completely missing. Maybe the average person wouldn't notice the flaws, but I do not believe that an average sample of the sheets available at either of my local Home Depot stores would pass independent testing to meet the rated R value with so many voids and flaws. I love my local HD staff, see them almost daily, but this new product (which probably is cheaper for HD, but not for me) is a deal breaker.
Date published: 2013-01-14
Rated 5 out of 5 by from We used this on an addition. WIthout windows, or even all the metal around the addition, we notice at least a 10 degree temperature difference between inside and outside. This is with no door in place and outside air coming in through that opening. I'm looking forward to seeing how it performs come winter - but with 90+ temps lately - it's nice to walk into that space and work. It was a breeze to install and truly makes a difference. Would recommend to anyone - any extra R value helps in this economy!
Date published: 2010-06-30
Rated 5 out of 5 by from best performing product i have ever used! easy to handle and install, by bracing a wall with 1x4, this product will increase R value by almost a third! i built my home with this product throughout, and my energy bills are incredibly low! recommend to anyone!
Date published: 2009-11-13
Rated 1 out of 5 by from Extremely poor product! Home Depot replaced the Dow "Tuff-R" polyiso board with this new Thermax product. The Dow board is far superior to the Thermax board and carries an R value of 6.5 per inch as opposed to Thermax's 5.9 per inch. Since they're both priced the same, that's an effective 10% price increase for H-D for the equivalent R value. The Thermax board also delaminates during cutting and sends hundreds of "floaters"(small beads of foam) in the air when it's cut. Very annoying!!(and possibly a health hazard?). I've probably used 300 sheets of Dow Tuff-R over the years but I won't be buying the Thermax board. I've discovered that Menard's carries 3/4", 1" and 1 1/2" polyiso board with an R value of 6.5 per inch at a 10% lower price than the Thermax board. That represents a 20% cost savings for the same R value! Worth the trip to O'Fallon for large purchases. Whoever the HD merchandise genious was who thought this was a good move ought to be questioned at length on this one!
Date published: 2014-02-16
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