Since 1978

Our insulation covers your building,
our people cover the rest.

COMMON QUESTIONS AND ANSWERS ABOUT RMAX POLYISOCYANURATE FOAM PRODUCTS FROM OUR
TECHNICAL SERVICES DEPARTMENT

What are the flute spans for a product?
Please follow this link to the specification sheets:

                         ROOFING

What are the fastening patterns for a product?

Please follow these links to the specification sheets:

            ROOFING                 SHEATHING

             Also, see Technical Bulletin #105

What screw lengths are required for attaching Rmax insulation?

Consult the individual screw manufacturer. Consideration must be given to how far the screw penetrates through the substrate, i.e. a metal roof deck, or how much the screw imbeds into the substrate, i.e., wood deck.

Should I use a vapor retarder?

See General Notes for use of Rmax Roofing Insulation in low slope applications.

Do you have any data on I-120 Windstorm Classification?
Our popular Multi-Max^®FA-3 roofing insulation as well as other available products have been tested and have received the industry standard I-90. Although we have not tested to I-120, check with your membrane manufacturer; Rmax may be included in their approved assembly.

Under which membranes of roofing applications can foil faced insulation be included in commercial projects?
Thermaroof^® Plus-3 is designed for use under a ballasted membrane system. Thermasheath^®-3 or Thermaroof^® Plus-3 or TSX8500 can be used under a metal roof system.
Does Rmax produce 25 psi taper insulation?

Rmax manufactures insulation to 25 psi compressive strength by adjusting the process formulation. Upon request tapered material can be manufactured with this adjusted formulation, however, the ASTM D1621 test method for compressive strength requires parallel surfaces and minimum thicknesses not suitable for tapered material. Orders for tapered material specifying Type II Class 1, Grade 3 (minimum 25 psi) will be supplied with material that has been manufactured with our standard 25 psi formulation.

How do I install crickets?
Please use the following link to contact the tapered specialist:

   Jennifer Rhodes     Tapered Specialist                1-800-762-9462 Ext. 160

Is the thickness of the NB product just the insulation or the insulation and OSB?
The thickness noted with Rmax Nailable Base-3 and Vented Nailable Base-3 products is the overall thickness, including the wood components.

How is a vent ridge installed with the Vented Nailable Base product?

Cut the OSB and Vent Strips back the amount required by the vent manufacturer (do not cut insulation layer back). It is important to note that the vent space, thickness of the vent strips as well as ridge venting are all either specified by the project architect or the shingle/ridge vent supplier. RMAX makes Vented Nailable Base available in order to meet these market demands - RMAX does not specify the amount of venting or spacing. Please refer to our product datasheets for proper fastening instructions.

Can Nailable Base-3 be provided with substrates other than OSB?
Nailable Base-3 can be fabricated with various grades and thicknesses of OSB and plywood, including fire-treated or fungal and insect resistant.

Is Rmax polyiso foam Type 1 Class 1?
Thermasheath^®-3, TSX8500, Thermaroof^® Plus-3 products are all ASTM C1289, Type I, Class 1 products - Please refer to individual product data sheets.

What is the R-value of a product?

The R-values for a particular product are listed on the specification sheet for the product. Follow these links to the specification sheets:

            ROOFING                  SHEATHING

How much does Rmax insulation weigh?
Please follow the link to the product weights      page.

Can R-Matte^® Plus-3 be used as a vapor barrier?
R-Matte Plus^®-3 is a foil faced polyisocyanurate foam core insulation. The aluminum foil facer on both sides is considered a vapor barrier. The perm rating for R-Matte^® Plus-3 is less than 0.3 perm. Material with a perm rating of 1.0 or less are considered vapor impermeable or vapor barriers. If a vapor barrier is necessary, all seams and joints should be taped with tape that is also a vapor barrier such as aluminum coated polyester or aluminum foil HVAC tape.

Which side goes out on R-Matte^®Plus-3?
This product is designed to be covered with siding materials of wood, wood-based products, hardboard, aluminum, vinyl, brick or stucco veneers. The white-matte finished (non-glare) side of this sheathing panel is installed facing the outside of the wall structure when the exterior siding will be either wood, wood-based products, hardboard, aluminum or vinyl sidings. The reflective aluminum side of the sheathing panel is installed to the outside of the wall when the exterior finish will be either brick or stucco.

Are panels available in custom lengths, widths, or with scored facers?

Yes. Various lengths and custom cuts are available, as well as pre-scored facers. Consult your sales representative for details.

Is Rmax sheathing closed or open cell foam?
All Rmax insulations are closed cell polyisocyanurate foam.

What is the sound deadening effect? Has there been any testing?

Rmax insulation is intended as a thermal insulation only. Sound dampening is very dependent on the specific assembly and each assembly, i.e. application, would have to be tested. Rmax insulation would provide some minor sound dampening qualities but it has not been tested nor is intended for such use.

Are Rmax products available unfaced?

No. The facers lend important properties to the insulation boards and are part of the manufacturing process.

Corporate & Sales Office
Rmax 13524 Welch Road, Dallas, Texas 75244-5291 972 - 387- 4500
Fax: (972) 387- 4673
Plant Locations
Dallas, Texas 800-527-0890 (Central) Greer, South Carolina 800-845-4455 (Eastern)
Fernley, Nevada 800-762-9462 (Western)