Architectural Mansard roofs

[Shredocaster]

I have a mansard type roof placed on a building - a pitched from soffit to peak type roof but only a certain distance in (versus a complete roof structure) and unfortunately has a plywood interior on steel joists thus combustible. By NFPA standards and NFSA research this does have to be sprinklered BUT how does one calc this space. There is a 7 head clause in NFPA (11.2.3.4.2) BUT there are a few areas where there will be dormers and thus a full attic type calc should be applied.... 2350 ft sq (pitch and dry) on an inline calc just seems overkill. I am contemplating using the Tyco Attics to keep the head calc down and still maintain an attic type calc. Any one come across this and perhaps have a different suggestion?

 

[cdafd]

Is it built already?

 

[Shredocaster]

Yes. I know what your thinking ill bet - have them drywall then plywood then roofing on top... right?

 

[cdafd]

one option, but if not built yet change to wood that meets NFPA 13 for no sprinklers.

And all this wood is open inside the attic?? not just a facade?

 

[TravisMack]

Typically these are 10' or less wide. Depending on slope and such, you may have an issue with SSU anyway. I often see these as 4:12 slope. You are required to have a sprinkler no closer than 5' to the eave. Also, you are required to have a sprinkler within 12" of the peak. It is often near impossible to get the sprinklers at 6' apart in that situation. Tyco SD sprinklers may be your only option, unless you do baffles.

Travis Mack
MFP Design, LLC

http://www.mfpdesign.com

"Follow" us at

https://www.facebook.com/pages/MFP-Design-LLC/92218417692