It would be wise to check the specifics of that firewall. In my limited building experience, we needed 5/8 drywall for fire ratings.
Originally Posted by Shinnya
Yes, 5/8 is required for the ceiling. That is according to the plan. It is going to be fun job...
Originally Posted by resummerfield
First of all let me apologize for using industry terminology so freely, it's an occupational habit. I'll try and keep it in mind as I continue...
To make sure I understand your most recent statements correctly, let me ask the following questions:
1. Is the fire separation you refer to is for the floor overhead? (you referred to it earlier as exposed 3x12's @ 12" oc).
2. Do you know what fire rating this separation has to be? It is usually referred to as a "1-hour" or "2-hour" rating.
If the building is a stucture with masonary side walls and wood floor framing and 3 stories or less then a 1-hr horizontal fire separation can be achieved by applying a single layer of 5/8" Type-X gypsum board to the underside of the existing floor joists. A 2-hour separation would require 2 layers. Your wonderful movie showed a stair between the first and second floors. Any such stair would have to be enclosed with 1-hour or 2-hour walls. Any door in such rated walls would have to be fire-rated as well (1-hour wall requires a 45 minute door/frame and a 2-hour wall requires a 90 minute door/frame assembly).
Now with all this aside, the idea of framing the darkroom walls with studs that do not extend all the way up to the previously mentioned upper floor (ceiling) above does make it all the more important that these walls be 20 gauge (ceiling framing too) and be properly braced. By "braced" I mean that the design must resisit the tendancy of partial height walls to sway from side to side.
I saw your preliminary floor plan and it would be helpful to know how it relates to the existing side walls of the building. Some dimensions would be helpful as well.
I'm happy to help but I do need more information. ;-).
No need for an apology. I certainly understand it. Regardless, I sincerely thank you for your help. I mean I really appreciate it.
I wish I could show you the drawing. Maybe I can try to get it in PDF from my architects.
I do understand about the staircase to be firewalled and any doors in-between to be firerated. I am pretty sure that it needs to be 2-hr rated. A layer of 5/8 sheetrock on the ceiling of 1st FL is indicated on the drawing. Does the combination of a layer of 5/8 sheetrock on on the ceiling of 1st FL and a layer of 3/4 subfloor on 2nd FL create a 2-hr firewall? Anyhow that is how it is indicated on the drawing form the architects.
Just to give you an idea, the building is 20' wide and 150' deep on the first floor. On the second floor, 75' from the front is where the apartment is located. Also, we built an addition on the back part of the second floor (50' from the back of the building) which is going to be a part of business. This is the part where you saw the staircase going up in the 3D rendering. The front 2nd floor is supported by those massive 3x12 @ 12" OC.
So, you are saying that if the walls of the darkroom does not go all the up to the ceiling of 1st FL, it needs to be 20GA as well as the ceiling of the darkroom (which needs to be at least 2x6 as you mentioned earlier).
The only think I can add to the situation which may not be so clear from my drawing is that the room is attached to the perimeter wall which goes all the way to the ceiling. Does it make any difference? Do I still need to go with 20GA?
Also, in relation to this, what I was thinking while I was going through all of these was that why not use wood studs? I just thought that was much simpler answer. Can I do that?
I will try to get some measurements tomorrow with more complete version of drawing and some pictures of the space.
The complication of the project here is that this is temporary space which is going to come down later. But I do want to make sure whatever I do now makes a sense for the later part of the project such as use of space, cost and recyclablity of the materials that I use.
I am meeting my carpenter tomorrow at the site...
Just a quick note. I was unaware that you have architects already involved in the building. Are they also working on the darkroom project with you? I am compelled to be careful in such matters... professional courtesy and potential legal implications!
Please clarify your contractual relationship with the architects.
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