I have a customer requesting a drywalled basement ceiling that runs flat i.e. the whole ceiling is below the HVAC system with no soffits.
The area is 800 sq.ft. with no intermediate walls and the ceiling needs to be 9″ below the bottom of the I beams to fulfill his wishes.
My idea is to use 18″ long 1″x 3″s (attached to the top and bottom chords of the I joists) hanging down the 18″ needed. I can then attach 2″x4″s to the bottom, running parrallel with the I beams to hang the sheetrock.
My two questions/concerns are
1) Will nails put into the sides of the I joists affect the structural integrity of the laminations, especially with the weight of the wooden frame and drywall added?
2) I appreciate that my method is labor intensive. Does anyone have any simpler ideas for achieving the results (suspended ceiling with tiles not being an option)?
Replies
http://www.usg.com/navigate.do?resource=/USG_Marketing_Content/usg.com/web_files/products/prod_details/USG_Drywall_Suspension_System.htm
You will have to go to a commercial d.w. supply to get this.
Mike, I didn't see suspended dry wall ceiling on the USG site.
We use to use a type of hat channel suspended by heavey duty grid wire and special eye screws into the bottom of joist. Properly done it easily carried the 5/8 FC dry wall. It went up in much the same way a suspended tile ceiling does, and a little faster (course I was younger then :). Hanging the board was a little more difficult because you had to be carefull to not push the channel up on the first couple of sheets. After that the weight of the board was enough to keep the grid in place as you hung the remaining sheets.
Someone here might remember the system name, but it eludes me right now. it would be ideal for what he is going to do.
Man, I hate CRS.
Dave
I just ask for T-grid, and they know what I'm after.
Goes together like a tile ceiling, then you just screw the d.w. to it.
TRIGGER said:
63944.4 in reply to 63944.3
what exactully does thAt meaNMR SPHERE i CHALLENNGE YOU INTECIIUPLECFTUZAL DRAMAQ RUIGHJ5 NOW BBITYCH
1) Will nails put into the sides of the I joists affect the structural integrity of the laminations, especially with the weight of the wooden frame and drywall added?
The nails should not affect the structural integrity of the I-joists if you nail only to the 2x3 'flanges' top and bottom. These parts are made of solid lumber (fingerjointed for length, but that's not a concern unless you nail right into a joint) and should behave as any other piece of dimensional lumber would in response to nail penetration.
2) I appreciate that my method is labor intensive. Does anyone have any simpler ideas for achieving the results (suspended ceiling with tiles not being an option)?
This is a problematic situation. Unless you are willing to build a complete new structural frame tied to the walls, you will need to suspend whatever ceiling you do install, whether it's gyprock or tiles, because the ductwork hangs below the structural framing.
I do not think it is wise under any circumstances to install a solid gyprock ceiling in a basement, as there are too many mechanicals that could require maintenance or repair which will be hidden above it. Doing this essentially guarantees that at some point in the future, your client will have to pay someone to bust out some of that ceiling and then patch it back together again. The cause could be something as simple as a defective telephone line, leaky pipe, or the need for a run of coax for a satellite dish feed. With a solid gyprock ceiling, any of these small repairs will entail a messy demolotion and patch job that could have been avoided by installing a suspended tile ceiling which is made just for this situation.
If your client is determined this is what she wants, then you need to either use some sort of commercial hanger as suggested in another post, or build down the I-joist bottoms so you can apply strapping across the joist run. I don't think vertically hanging 1x3 would make a good supporting frame for strapping; it seems to me it would tend to wobble sideways quite a bit, thus obliging the gyprock to act structurally where it touches the sidewalls, and placing lateral stress on it which would then encourage screw pops and joint cracks.
I'd suggest instead that you frame some skeleton railroad trusses on the bottom flanges of the I-joists to build down the required 9 inches. You should be okay building down only every second truss unless they are on 24" centers. Then strap perpendicular to those on 16" centers and attach the gyprock to the strapping.
Dinosaur
A day may come when the courage of men fails,when we forsake our friends and break all bonds of fellowship...
But it is not this day.
Edited 10/8/2005 8:34 pm ET by Dinosaur
1) Will nails put into the sides of the I joists affect the structural integrity of the laminations, especially with the weight of the wooden frame and drywall added?
The nails should not affect the structural integrity of the I-joists if you nail only to the 2x3 'flanges' top and bottom. These parts are made of solid lumber (fingerjointed for length, but that's not a concern unless you nail right into a joint) and should behave as any other piece of dimensional lumber would in response to nail penetration.
Actually not true, as I found out to my cost. Nailing into the side of an I-joist flange can destroy it structurally. The flange is made up of layers glued to each other, and forcing a nail between the layers can separate them. I had to tear out some I-joists for exactly this reason.
Anybody planning to stick a nail into the side of a flange should call up the manufacturer and check on this.
Interesting. You must be using a different sort of I-joist than those I see here. The flange element in all the ones I've ever seen is nothing but a 2x3 with a groove routed in the flat for the beaver-barf. When the I-joists are longer than 16', the 2x3's are finger-jointed end to end.
Dinosaur
A day may come when the courage of men fails,when we forsake our friends and break all bonds of fellowship...
But it is not this day.