Building Official FAQs

Q What requirements are there for thermal insulation?

A Section R 316 of the IRC requires cellulose insulation to pass the following tests:

• ASTM E-84
• Consumer Protection Safety Commission 16 CFR parts 1209 and 1404
• Additionally all thermal insulation must follow the Federal Trade Commission rule 16 CRF part 460

Q How do I know Nu-Wool Insulation has passed the required tests?

A As noted on our bags and in our bags and in our literature, Nu-Wool insulation is an Underwrites Laboratories Classified Product. Nu-Wool uses UL as an independent certified third party to conduct all of the required tests. A copy of compliance is available from Nu-Wool and from UL on their web site under "certifications."

See UL classification documents R-8078 & R-8078-B

Q Who designed the tests?

A ASTM is responsible for writing the test standards. ASTM C-739 provides most of the test procedures while ASTM E-84 and E-970 provide the standard to determine flame spread and smoke developed as well as critical radiant flux respectively.

Q What is the insulation tested for?

A ASTM C-739 outlines test procedures for the following physical properties of cellulose insulation:

• Design Density
• Critical Radiant Flux
• Fungi Resistance
• Odor Emission
• Smoldering Combustion
• Thermal Resistance
• Moisture Vapor Sorption Corrosion

See UL classification documents R-8078 & R-8078-B

Q Can Nu-Wool Insulation be left exposed?

A Yes, ASTM test E-84 is used to determine the flame spread and smoke developed from the insulation. With a flame spread of 15 and a smoke developed of 5 Nu-Wool is considered a class I building material.

Q Can Nu-Wool be used in fire walls?

A Yes, in fact there are over 45 fire wall assemblies using Nu-Wool listed on the UL website.

See Firewall page

Q What testing is done for fire walls?

A The ASTM test standard E-119 is used by an accredited lab to do live burns of actual wall sections to determine how long the assembly will hold up in either a fully loaded condition as in a bearing wall or in a free standing wall used only for partitions.

See Firewall page

Q Do you use a vapor retarder with Nu-Wool?

A Building science has shown that the water vapor going into a wall cavity is dependent on air movement more so than diffusion. Building science has also determined that vapor retarders can trap moisture inside a wall. Because of its unique ability to resist air movement, and therefore, the transmission of moisture, a vapor retarder is not necessary with Nu-Wool Premium Cellulose Insulation.

See Vapor Retarder page

Q What do the building codes say about vapor retarders?

A Starting with the 2003 IRC vapor retarders were required only in certain geographical areas, and the code contains an exception where other approved means to avoid condensation are provided. The 2007 supplement to the 2006 IRC removes the vapor retarder section completely.

See supplement to IRC
See supplement to the IECC

Q Does Nu-Wool allow one to fill a cathedral ceiling space and eliminate the attic venting?

A Yes, Nu-Wool has been showing its installers how to properly dense pack a cathedral ceiling for over 15 years.

See Cathedral Ceilings page

Q How soon can drywall be installed over the Nu-Wool Wallseal?

A Under most conditions gypsum board can be installed 24 hours after a 2x4 wall cavity has been filled and 48 hours after filling a 2x6 wall.

See 3-Part Specification page, part 3.2

Q Can Nu-Wool be used to seal around chimneys and heating appliance exhaust flues?

A No, the code as well as most flue and chimney manufactures require a minimum air space between them and any combustible material.

Q Is an ICC-ES report required for a building material to be used?

A No, ICC does not do any of the required testing. A ICC-ES report basically takes all of the available product test data, reviews it and assembles it into one report.