Frequently Asked Questions

What are R-value, k-value, and U-value?

R-value is defined as resistance to heat flow. For example, the R-value of 2" Multi-Max FA-3® is 12.1 (°F*sqft*hr)/Btu.

k-value is defined as heat transmission per inch of material. For example, the k-value of 2" Multi-Max FA-3 is 0.165 Btu/(°F*sqft*hr).

U-value is defined as the inverse of the total thermal resistance of an assembly. For example, an assembly made of 0.625" plywood sheathing (R-value = 0.77) and 2" Multi-Max FA-3 would have a total R-value of 12.87 (°F*sqft*hr)/Btu resulting in a U-value of 0.078.

How do I fasten your sheathing products to a wood or steel stud wall?

R-Matte Plus-3 may be secured to the studs, wood or steel with bugle-head screws, galvanized roofing nails or common nails driven through cap washers.

What do I do if Rmax insulation becomes wet?

DO NOT use wet insulation products within a roofing or wall assembly. Installation of wet insulation or other system components shall cause the Rmax warranties to become void. Rmax insulation that has become wet may experience dimensional stability problems, and every precaution must be taken in order to determine if the insulation is still usable. Rmax insulation that has become wet may only be applied in a roof or wall system if dimensional changes have not occurred and after it has been dried thoroughly. All other system components shall be stored as recommended by the supplier.

What is LTTR and why doesn’t it apply to foil faced products?

Long Term Thermal Resistance (LTTR) is a method of determining the R-value of a product. LTTR values are determined in accordance with CAN/ULC-S770, which predicts a 15-year time-weighted average. This test method applies to permeable faced products. Therefore, it is not applicable to foil faced products, such as R-Matte Plus-3 or Thermasheath-3, which use the PIMA 101 conditioning methods and ASTM C518 measurement procedures.

Do Rmax products harm the environment?

Rmax products utilize an HCFC and CFC-free blowing agent that essentially has zero ozone depleting potential.

Do Rmax products qualify for LEED credits?

Yes, see Rmax Technical Bulletin #106 for more information.

Are Rmax products Energy Star approved?

Yes, the Energy Star logo is displayed on our R-Matte Plus-3 and Thermasheath-3 products.

Do Rmax products qualify for a Federal Tax Credit?

R-Matte Plus-3 and Thermasheath-3 are an efficient thermal insulation board composed of a polyisocyanurate foam core and covered with aluminum facings on both sides. It is suitable for use in residential applications for improving the energy efficiency of a home.

A recent tax law change provides a tax credit to improve the energy efficiency of existing homes. The law provides a 10 per cent credit for buying qualified energy efficiency improvements, including but not limited to insulation systems that reduce heat loss/gain. This letter certifies that R-Matte-Plus-3 and Thermasheath-3 comply with the requirements and qualifies for the Federal Tax Credit for existing homes in the Energy Policy Act of 2005.

What is the highest temperature that R-Matte Plus-3 can be exposed to?

R-Matte Plus-3 is suitable for applications with temperatures of up to 250°F. However, it cannot be exposed to open flame or other sources of ignition.

Why is there a white side and a reflective side on R-Matte Plus-3?

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

Can R-Matte Plus-3 be used in a garage door application?

Yes, R-Matte Plus-3 is allowed to be used in a garage door by exception to the International Building Code, Chapter 26. Typical installation to the door is with minimal quantities of adhesives such as liquid nails.

Why is there a Do Not Leave Exposed Warning on the R-Matte Plus-3, Durasheath-3 and Thermasheath-3 products?

These products are classified as foam plastics, which according to Chapter 26 of the International Building Code, must be separated from the interior of a building by an approved thermal barrier.

Is R-Matte Plus-3 fire rated?

R-Matte Plus-3 is listed as a Class B according to the International Building Code (ICC) Section 803 Wall and Ceiling Finishes. Class B is designated as having a flame spread of 26-75 and a smoke developed index of 0-450. R-Matte Plus-3 must be fully protected on the interior side of walls by a minimum of 1/2 inch thick gypsum board or equivalent thermal barrier.

What below grade applications can Rmax products be used in?

Thermasheath-3 and R-Matte Plus-3 are suitable for use in below grade applications such as crawl spaces and slab-on-grade. For further information, please contact the Technical Services Department at 1-800-527-0890, x106.

What is the R-value of Rmax products?

See specific product Data Sheets

Does Rmax offer a tapered takeoff service?

Yes, please contact our tapered department -tapered@rmaxinc.com

What type of fastening patterns are recommended for Rmax Nailable Base-3?

See specific Nailable Base Data Sheet