Basement Fiberglass Insulation

[Ed-in-PA]

If a basement is "not considered habitable" because the ceiling above is insulated per code, yet one or more walls have been framed out with studs (either a framed daylight basement wall or other framed wall in front of the concrete wall) and these walls are insulated with fiberglass batt (either faced or unfaced), do the fiberglass insulated walls need to be covered with a thermal barrier to satisfy the code? Or, should there be different requirement for faced verses unfaced. Remember the basement is "not considered habitable". In my opinion, the IRC is not clear on this.

 

[mjesse]

I would go to this;

2006 IRC

R316.1 Insulation.

Insulation materials, including facings, such as vapor retarders or vapor permeable membranes installed within floor-ceiling assemblies, roof-ceiling assemblies, wall assemblies, crawl spaces and attics shall have a flame-spread index not to exceed 25 with an accompanying smoke-developed index not to exceed 450 when tested in accordance with ASTM E 84.

Exceptions:

1. When such materials are installed in concealed spaces, the flame-spread and smoke-developed limitations do not apply to the facings, provided that the facing is installed in substantial contact with the unexposed surface of the ceiling, floor or wall finish.

2. Cellulose loose-fill insulation, which is not spray applied, complying with the requirements of Section R316.3, shall only be required to meet the smoke- developed index of not more than 450.

It's not a concealed space, so the flame spread requirements apply.

Whether that means a thermal barrier is required, depends on the insulation specs.

Just $0.02

mj

 

[TJacobs]

What mj said. Unfaced fiberglass generally would not need a thermal barrier. Kraft-faced batts generally do need a thermal barrier. Foil-faced could go either way. The need for a thermal barrier is usually marked on the facing.

 

[Architect1281]

True it is the Facing is what spreads the flame, Had one contractor who new this fact and that Kraft face required covering.

Proudly pointed out that thats why he used the Foil Facsed Insulation that for him had the exact smae instructions on it.

Unfaced does not require the thermal barrier. at least in Fiberglass.

 

[JBI]

Manufacturers specs

 

[Francis Vineyard]

Ed-in-PA

Welcome to the board, hope you come back often and enjoy learning from some of the best professionals IMO.

Note where mjesse invited R316.1 "crawlspaces and attics" and as where applicable in other sections of the code, combustible materials is not limited to walls and ceilings of "habitable" spaces but applies to all occuppiable spaces such as garages, accessory buildings that require a permit and spaces including ducts and chimney chases.