Message to Our Customers

Rmax R-Matte

Model # W-N5075X

Internet # 100317820

Store SKU # 464947

Plus-3 - 3/4 in. x 4 ft. x 8 ft. R-5 Polyiso Rigid Foam Insulation Board

This item has been discontinued.
The Home Depot no longer carries this specific product.



Model # W-N5075X

Internet # 100317820

Store SKU # 464947

R-Matte Plus-3/Thermasheath-3 is rigid foam plastic thermal insulation board composed 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 R5 with dimensions of .75 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 ridgid foam board offers superior fire protection properties compared to any other ridgid 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 tranmission 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.) 
.75 in 
Product Width (in.) 
Insulation Application Type 
2x4 Walls,2x6 Walls,Attics,Basements,Ceilings,Crawlspaces,Exterior Sheathing,Garage,Re-Siding 
Insulation Type 
Product Weight (lb.) 
7 lb 
R Value 
Sheathing Type 
Warranty / Certifications
ENERGY STAR Certified 
Warranty Information 
Standard Manufacturers Warranty 


Rated 4.9 out of 5 by 10 reviewers.
Rated 5.0 out of 5.0 Great stuff I used this product to make an enclosure box for my attic stairs. Just a little something to fit over the attic stairs when they are closed to prevent heat and cooling loss. It worked perfectly. It's very easy to cut with a razor knife and a drywall square. It actually cuts very similar to drywall. It does a great job at insulating too. I notice a huge difference in the surface temperature of my pull down attic stairs. Before when the attic stairs were closed the surface of the stair hatch was hot to the touch, now it is closer to room temperature. not to mention I have less air loss. I will be using this more. July 15, 2014
Rated 5.0 out of 5.0 by Great insulation for garage doors! I ordered this online and it was ready for me at the store as soon as I placed the order. I cut it in front of the store to fit into my car. I placed some 3" x 12" foam board spacers to give the air space and placed the foil side towards the inside of the garage doors to reflect the heat. June 9, 2015
Rated 5.0 out of 5.0 by R-Matte Drops Attic Temp 20 Degrees Last summer I determined to do something to lower our electric bill. Several options would serve to better insulate and lower the heat transfer into the house. But the best idea seemed to prevent the heat from getting into the attic in the first place. I needed more insulation over the joists and we needed new insulation over the metal duct work on our 30 year old home. If the attic can be made cooler, then it would transfer through the AC ducts and through the ceiling. I purchased 5 to 10 R-Matte boards at a time and secured them to the under side of the roof rafters. In most cases the end of the 8 foot foam boards met on a rafter. Sometimes I cut a few inches off or even added a 2x3 board to one side or the other of the rafter and secured them. I used 2" wood screws and a 1" plastic washer from roof shingle nails. Previously the attic would get 120 or more and now stays in the mid 90's. The AC use to run most of the time and when we use it, cycles on and off quickly. You must have good sofit ventilation and in our case we have ridge vents. The roof decking gets hot and the air below must have a free flow to carry the heat out. This summer I am adding a secondary vent to our porch area because the attic now needs air flow in and out since the foam boards have isolated the soffits from the attic. R-Matte is the way to go. If you can do it yourself, do a little each week and enjoy a cooler home. April 28, 2009
Rated 5.0 out of 5.0 by easy to use Several rooms of our 2-story house have walls that are exposed to attic space on the back side. In several locations, the fiberglass batts had drooped from between the studs, leaving the backside of the drywall exposed to extreme hot and cold of the attic. I used this product to provide a rigid support to hold the fiberglass in place between the studs, as well as adding an additional R-5 on the attic side of the wall. It's easy to cut to end on studs or fit odd shapes with a household razor or sharp knife. I attached with roofing nails (with plastic washers) across the attic side of the studs. This product is lightweight, so few nails are needed. Note: this product acts as a vapor barrier, which you don't want on the (cold) attic side of the wall. Don't seal the edges to make it airtight or you risk water condensing inside the wall cavity. January 28, 2010
Rated 4.0 out of 5.0 by Rigid Insulation I own a drywall construction business in Florida and this is a great product for use on concrete or c.m.u. walls. It is easy to cut and install and provides good insulation for exterior walls. It also has moisture protection qualities as well as sound deadening qualities. It works great in conjuntion with either 1x2 p.t. furring strips or 7/8" metal hat channels over top of the insulation allowing an air space and creating an overall 1-1/2' thickness to allow for standard electrical box installation on c.m.u. walls without having to break out the block for the boxes or e.m.t. conduit. July 28, 2010
Rated 5.0 out of 5.0 by Works in a deep freezer's door. I have a deep freezer out in the garage. The original insulation of the freezer door collected ice and the old inside hard plastic broke apart. I needed away to insulate the freezer door. Between my brother and I. We came up the idea to us a foam insulation board. So I got the insulation board and cut it to size to fit the inside of the door. Then I use the expanding foam around the edges of the insulation board. The expanding foam (when dried) will hold the insulation board in place and also seals out the moister between the insulation board and the freezer door. It has been over a month now and I have no trouble with the foam insulation board in the freezer door. Also no sweating on the exterior side of the freezer door. October 25, 2011
Rated 5.0 out of 5.0 by Insulate your Garage Door!! Much cheaper than buying the kits. Two layers of this is the perfect thickness. Just cut it slightly oversize, slip the top edge under the lip and then slide the bottom edge down. You could also glue it with spray contact glue. Four sheets was just enough to do one single bay door. June 18, 2012
Rated 5.0 out of 5.0 by Made a solar heater with it Too many years ago Mother Earth magazine had an article describing how to make a solar powered window heater. We bought this stuff, some black paint and a pane of glass. We already had the duct tape and knife. Made the window heater as per instructions. Stuck it in an east facing window. It worked perfectly! That was when I lived in northern Louisiana. Later, when I built a barn, I used it as insulation under the tin roof. Again, no complaints. The backing makes it stronger than plain poly boards. Those things broke way too easy. September 11, 2014
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Store Exclusive. This item is available for purchase in select stores only.