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KemoSabe
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I've built them in the past. Fire treated framing lumber, fire treated plywood under 5/8 T&G with fiberglass/resin topper. Underside covered with 1/2" Hardie.
 

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Has anyone built a deck with the bottom requiring a 1 hr fire rating?

The deck will be less than 4' off the ground.

Roughly 20 square fee, its just the rear entrance.
fire treated lumber and IPE. HD is carrying fire treated lumber but not sure about the exterior part of it.

Scratch the wood framing. do it in galv light metal gauge steel and ipe.... IPE has rating of concrete.
 

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Actually, everything written here by all the respondents, including myself, is wrong. Metal studs and pavers do not have a fire rating, they are just considered non-cumbustable construction. Ipe most certainly does not have the fire rating of concrete, while it has a low flame spread, it is a combustable product.

Fire rating is an assembly. 5/8" GWB has no fire rating until it is part of an assembly of building materials including fasteners and framing materials.

Fire retardant treated wood has a surface burning classification and, by itself, does not have a resistance rating in hours any greater than untreated wood. Fire ratings in hours are assigned to door, wall, or deck assemblies following testing in accordance with ASTM E 119 and E 136. The references such as the Underwriter Laboratories "Fire Resistance Directory" specifically points out that FRT wood may be substituted for untreated wood in any related assembly. Dricon FRT wood can be used as a component of such assemblies in structures where the code does not permit the use of untreated wood.
http://www.archchemicals.com/Fed/WO...on/properties.htm?selLocation=fire.htm#spread

http://www.advantagelumber.com/ipe_decking_blog/ipe-decking-fire

Why does the inspector say the underside of the deck needs a rating? What kind of construction is this? Are there plans and how did this mistake get past review?
 

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I have done it once. Cantilevered balcony that needed to maintain a 1 HR rating to seperate living floors in an assisted living building.

This is how it was designed:

5/8" Type X (1 Layer)
1/2" RC
2"x10" PT Joists
3/4" PT Plywood
2x PT Sleepers
Waterproof membrane
Composite decking

The upper balcony needed to be protected by the automatic sprinkler system as well.

Very expensive and a PITA.

Looking back, a structural steel composite beam and column system with metal decking and light weight concrete would have been a better system.
 

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Actually, everything written here by all the respondents, including myself, is wrong. Metal studs and pavers do not have a fire rating, they are just considered non-cumbustable construction. Ipe most certainly does not have the fire rating of concrete, while it has a low flame spread, it is a combustable product.

Fire rating is an assembly. 5/8" GWB has no fire rating until it is part of an assembly of building materials including fasteners and framing materials.


http://www.archchemicals.com/Fed/WO...on/properties.htm?selLocation=fire.htm#spread

http://www.advantagelumber.com/ipe_decking_blog/ipe-decking-fire

Why does the inspector say the underside of the deck needs a rating? What kind of construction is this? Are there plans and how did this mistake get past review?
Ok I guess I'm wrong. Did find this pdf NYC I did read somewhere there it was rates class A http://www.nyc.gov/html/dob/downloads/pdf/409-03-m.pdf

http://www.aeratis.com/?p=111
 

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Artist and not a curator
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I don't remember who makes it but there is a 1hr coating that can be sprayed directly onto combustibles (it looks like rhino liner for a truck bed). It was pretty expensive for a couple thousand sq ft.. For some reason it was an insulation company who offered it.
 

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We did a feature ceiling in a resort hotel, made out of cedar.
It was sprayed with a fire resistant clear varnish, as spec'd
Sorry, but I don't know the name of it, but it worked.
We ran our own un-official tests.
 

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I don't remember who makes it but there is a 1hr coating that can be sprayed directly onto combustibles (it looks like rhino liner for a truck bed). It was pretty expensive for a couple thousand sq ft.. For some reason it was an insulation company who offered it.
Probably intumescent paint. It's what's applied to spray foam insulation for a fire resistant coating.

It is really a question of whether you need a 1 HR rated assembly or fire resistant materials.
 

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always building
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"… decks shall be a minimum of 1-hour fire-resistance-rated construction, heavy timber construction, or constructed of approved noncombustible materials or fire-retardant-treated wood identified for exterior use and meeting the requirements of Section 2303.2 of the International Building Code."...
Like I said,,, 4x material
 
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