3/4" Tongue and groove pine as a thermal barrier over spray foam

[jwilly3879]

Is anyone allowing 3/4" tongue and groove pine boards to be used as the required 15 minute thermal barrier over spray foam insulation?

The reason for the question is I am seeing more spray foam insulation and the SPF contractors seem reluctant to tell the contractor/homeowner about the requirement for a thermal barrier or ignition barrier. I am located in Climate Zone 6 in NY and when open cell SPF is used a Class I or II vapor retarder is required in addition the the thermal barrier.

When doing the insulation inspection I generally ask what will be used for the thermal barrier, 1/2" sheetrock or an intumescent paint product and the usual response is "what are you talking about?"

I have heard that NYSDOS is working on a table of 15 minute thermal barrier equivalents based on Chapter 7 of the Building Code.

 

[elowpop]

I haven't seen lumber like that in 55 years

If you got it I think it's perfectly acceptable.

 

[Builder Bob]

It may be possible, I know that 5/8 inch Sp was only good for 10 minutes in this test series - http://www.fpl.fs.fed.us/documnts/fplrp/fplrp408.pdf

(PS... 3/4" inch Sp only lasted for 13 and 14 minutes in this test results....)

 

[rleibowitz]

Yes, over 1/2 inch sheet rock.

 

[Coder]

Just from memory (which isn't all that great ) As long as it meets the flame spread and smoke density requirements. It is acceptable.

 

[DRP]

I've put up miles of it in ceilings over foam, R316.5.2