Fire Rated Ceiling above studio ceiling...

Hello, wondering if anyone knows of a UL listed fire-rated (2hour) construction of a ceiling where the drywall is put up in between the floor joists of the above floor? I am trying to achieve my fire rating in the buildup of the above floor layer so I can freely run HVAC, electric and other stuff between the joists and save valuable ceiling height for the studio. -ashley

Bump? Rod? thought you might have an answer on this. Thanks, ashley

bassman wrote:

Bump? Rod? thought you might have an answer on this. Thanks, ashley

Ashley, I'll look into UL assemblies this weekend - BUT - my guess is that what you depict doe snot exist as a rated assembly - this because rates assemblies (much like acoustical assemblies) make use of an air space between 2 surfaces.......... However - it is possible that the 2 seperate assemblies might have been tested as a rated assembly -0 we'll have to see. Post a picture of exactly (and I do mean be very VERY precise) what it is you have including the finish you propose...... Rod

Hard to be fire rated when the joist ,which is wood, is exposed..are the joists fire treated? if not I would say no.. you would have to cover the ceiling completely . and I believe one layer of 5/8 board will only give you a 1/2 hr rating then with air gap to next 5/8 board that will give you an hour rating. Now Im not sure of the size of the Air gap but on a standard 3 1/2 inch stud wall you will get an hour from one side to the other..

Yeah, I'd guess you'd have to at least ultimately cover exposed areas of the joists with Type X drywall. I also question the need for the upper half of a ceiling assembly to be fire rated... Isn't the rating based on fire breaking out on the finished side anyway? Perhaps you can elaborate more on your situation and include a side view illustration that depicts the floor of the room, the walls and ceiling of the room, the air gap above the ceiling, and the floor above. I'm just wondering if you might possibly be worried over nothing. --Keith :mrgreen:

I guess my response to Rod got lost in the shuffle. :( I am trying to avoid the need for fire dampers on HVAC runs that penetrate the lower ceiling of the studio. They are expensive and I would like to get some more bang for the buck in building up the upper layer. I need to post some design work as well. around 1500 sq ft with two control rooms, large booth and main recording room with a machine room as well. Navigating the fire rating between rooms and HVAC become quite a hassle and can limit things. If the fire rating is above, I'm free to do more stuff below. -ashley

OK, that clears it up -- it's fire damper avoidance strategy and maximum headroom salvaging. That's the piece I wanted to get clarified, because I'm curious what Rod might have to say about that... Pennywise and pound foolish? Unnecessary? I just don't know... But I'm now very curious. :-) Will you be interleaving your lower inner leaf joists between the outer leaf (existing) joists? If so, are you planning to use cross bracing as illustrated in Rod's book? The reason I ask is that you'll see there are a few inches that must be allowed for them... :roll: --Keith :mrgreen:

Ah yes, Keith. Crossbracing..... hmmmm..... My hope was to do something as close as possible to the diagram from Rod's book. If I can keep the fire rating above the bottom of the existing joist, I can save valuable inches. The floor to bottom of joist now is around 9' so I have room to play but don't want to end up with an 8' ceiling. Also, my machine room I wanted to be sort of the inside remainder of the other rooms, that is, I don't want to build separate walls and ceiling for that room. I have a fire rating issue right there.... It would just be so much easier if the fire rated layer was separate and complete before any studio walls go up. I still have plenty of design time to figure it out. I have pics and will need to get them up soon. -ashley

Pics of my ugly church basement... We (my wife and I) bought this church and have been renovating the upper floors into high end apartments. This is the basement beneath the first unit. The main sanctuary is going to be a rental hall for weddings, receptions etc... And also a recording room for the studios 8) In these shots you can see where we have demoed into the ceiling to run some gas and electric to upper floors. These joists rest on masonry and 15" steel beams. -ashley