Thread: "Fireblock" or "separation"

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Some will say it can be left with no ceiling.

I disagree.

Jerry,

"Some will say it can be left with no ceiling."

Why would they say that? Isn't that a natural fire chase?

I would think it should be sealed unless the door to the closet was a solid core or metal without any penetrations. However, if they are taking the combustion air from the corridor, that's not gonna work either.

Originally Posted by Jeff Eastman

Thanks Jerry, but is the ceiling for "separation" or for being a "fireblock"?

More for separation anxiety issues - that's what the psychiatrist said anyway.

Being as the ceiling is not a "fire rated assembly", the only fire blocking would be in the concealed spaces within the walls.

It's more for "separation", energy code, etc.

As Tim was alluding to, if there is no ceiling in that closet, there is no insulation, that means the entire closet and its door needs to be insulated and the door weather stripped, no openings to the 'house', and two pipes sticking down into the closet, one high and one low.

You would then think of the unit as being 'mounted in the attic' which is what it basically would be, although a confined attic with limited working space. You would need to apply all requirements for appliances in attics, etc.

That means the 'walls' are now considered 'ceiling area' and would need the higher R value insulation required for 'ceiling areas' than what would be required for 'wall areas'.

Just opens a whole big can of worms.

I would recommend they bring the entire closet to 'current code standards, which typically include a ceiling and combustion make up air vents' and let the contractor figure out what that 'current code' is.

This way, you've made the recommendation to install a ceiling, and 'reminded' the contractor about combustion make up air, then advised 'current code', which will kick in all the other things required too, insulation, etc.

Personally I agree with east coast Jerry's premise, but the actual fact is the only place in a R-3 occupancy, (single family residential dwelling), a fire separation is required by the building codes is between the house and an attached garage, Group U. Other than that the home could have totally exposed framing and the only coverings required would be the building envelope (exterior). Bottom line; no ceiling covering required by code in that mechanical closet.

Originally Posted by dan orourke

So then the 1/8 inch thick cover is okay. Who would've thunk it.

Would 1/8 inch meet minimum roof sheathing thickness? Nope.

This is what Jerry Mc. is saying: Consider an open ceiling living room (or entire house) with exposed beams. The roof sheathing would need to be thick enough to: a) span beam-to-beam, and, b) meet minimum roof sheathing thickness. In some areas you might get by with 3/8 inch roof sheathing, but the span might only be 12 inches - beams 12 inches apart? Not likely.

So, move the beams to 4 feet apart, that 'looks nice', however, you will now likely need 2x T&G roof sheathing.

And don't forget the insulation. In the above case, it would need to go 'on top' of the roof sheathing.

Dan
Think of a home as a cardboard box. The cardboard thickness and energy format is dictated by the local adopted building codes and of course should be moisture proof and depending on location to the property line, fire protected. What folks have inside is up to their crazed decorators if they have money or if they don't what they can afford at Ikea.

Originally Posted by Clay White

The cover to the ladder system was, like stated above, 1/8" thick. I understand the insulation on the cover was not at the proper R-thickness (just 1") for living spaces, but the thickness of the cover proper separation between living space to attic still has me confused based on your posts.

Jerry P: It sounds like you are saying that for MY scenerio, the thicknes of the cover is NOT proper, correct?

As long as the insulative R-value was proper, and you said it was not, then the 'ceiling' holding the insulation up could have been a radiant barrier (see other thread for discussion on radiant barrier), perforated of course so it was not also a moisture barrier (as long as it also serves as a vapor retarder, and I doubt it does). As long as it was thick enough to support the insulation. I don't recall anything stating that the ceiling has to be 1/2" gypsum board to protect the roof structure.

What I'm saying is: It is not the "thickness" of the ceiling, but the "material" and it's qualities - I'm just using the radiant barrier for this example because it is a 'very thin material'.

Our right coast Jerry P is getting into CA Title 24 if he where living on the left coast, where home inspectors need not tread. However, go back to my original statement, aside from property line set-backs under local dwelling exterior fire code regulations and ordinances, state adopted building codes, and attached garage fire wall separations the entire dam house could be open framing. Some folks may even like that idea, but I don't find it particularly cozy, especially either in winter or when we have friends over.