Shop/Garage ceiling question..

[blakjak220]

The building: A 15'6" wide, 35'6" long, stick built, concrete slab, 2x4 framing (mostly on 24" centers, some closer to 18inch... previous owner built it and wasn't really particular with spacing apparently). Walls are 12'6" high and it has manufactured trusses on 24" centers, architectural shingle roof.
The question: I don't have a need for over 12' of interior space and am not sure I want to cool/heat that much (will be a large window unit). Also, the previous owner installed a 15ft garage door on one end and so the framing is lower on that one end and it would be a huge hassle to undo all that to have an even ceiling all the way across. So I was considering lowering the ceiling a couple feet, say to an even 10ft. With a little over 15' span from side to side what would I need to frame it with to be strong enough to carry several florescent light fixtures, it'll be sheathed in, most likely, 7/16th OSB, probably have some dust collection ducting attached to it at some point and will have loose fiberglass insulation blown in. I was thinking 2x8's on 24" centers? Maybe strapped to the joists above somehow? Could I get away with 2x6? or do I need them closer together? My plan was to attach a horizontal beam (say a 2x8 or 2x12) at the ceiling height then attach new joists to it with metal brackets. If it matters, the walls with be insulated with fiberglass batt then also covered in either 7/16 OSB or ply.
Any thought or suggestions would be helpful. And I could add some pictures if needed later.

Thanks

 

[blakjak220]

 

[ckyle29]

Your post doesn't mention anything, but the first thing you need to find out is what the dead load for the bottom chord on your trusses is. That will determine what you can or can't do with the ceiling. If you know who built the trusses, you could ask them, otherwise you will need to hire an engineer. Otherwise you run the real risk of ceiling collapse, which will definitely ruin your day.

 

[blakjak220]

I'm not sure who built them but there's a company who manufactures them right down the road so it was likely them. Do I just need to know the specs for the trusses so I can use them to support the dropped down ceiling I want to put in? I guess I was thinking I could make a lower ceiling out of 2x6-8's and not have to worry about how much load the existing trusses can handle. Am I looking at this wrong?

 

[maxpower_hd]

I understand about the heat but a high ceiling is quite nice to have. Mine is just under 11. I have no issues heating it because I only go to about 55-60 most of the time I'm working and leave it at 45 when I'm not. You could always us ceiling fans to circulate the heat.

Another option is a simple hung ceiling. Those just use wire and small supports to hang which I'm sure would not be a load issue.

I could be wrong but I believe the trusses are generally engineered to at least hold a ceiling of sheet rock. I'm sure the place near you could at least tell you that even if they didn't build the trusses.

 

[Samh]

From a cooling perspective, the height is nice, because the heat will go up. On my old 2 story barn, it was like a different climate going from the first floor to the second floor.

 

[blakjak220]

Well... I may just need to go ahead and finish out the ceiling where it's at... I'll have to think it about. Thanks guys.

 

[NUTTSGT]

Well... I may just need to go ahead and finish out the ceiling where it's at... I'll have to think it about. Thanks guys.

That's what I would do and leave it as is. Since you're in Arkansas, I'd think you'd be more worried about cooling it rather than heating it. Once you get it insulated and a ceiling put in, you should notice a difference right away during the Summer months.

 

[ckyle29]

I could be wrong but I believe the trusses are generally engineered to at least hold a ceiling of sheet rock. I'm sure the place near you could at least tell you that even if they didn't build the trusses.

Actually, most trusses are designed for what the buyer tells them to design them to. Many are built only to support the weight of the bottom chord and maybe a little wiring, but nothing more. Those trusses will have a bottom chord dead load of maybe 1 pound per square foot and are not meant to have any ceiling or many lights attached to them. This is why it is so important to know what the bottom chord dead load is. 1/2 inch sheetrock weighs about 2.2 PSF, so you would easily exceed your dead load before putting any lights, wiring or insulation in. Sheetrock is actually heavier than regular plywood, OSB or metal for a ceiling.

Here is a good read regarding ceiling loads. It is for pole-barns, but the information is still valid whether it is a barn or a shed:
http://www.hansenpolebuildings.com/blog/2013/03/ceiling-loads/.

 

[blakjak220]

Definitely more worried about cooling than heating.... keeping the air dehumidified is the other top priority so my tools won't keep rusting away. It was so hot and humid here last summer (my shop was in the uncooled garage) that I just gave up for about a solid month. So hot I was dripping wet after about 2 mins, just not worth it.
The only obstacle to just making the ceiling 12 foot is the previous owner "reengineered" the first 12 joists in order to install an overhead door. Undoing his disaster is going to be a real chore.

 

[bczygan]

If you do decide to put a lower ceiling and just need insulation and lighting, then use a dropped lay-in grid ceiling like many offices use. It is lightweight and is suspended from wires, so it can easily be removed later. Lights drop right in and insulation can be laid in over the 2'x4' lay-in ceiling tiles.

 

[blakjak220]

Thanks for the article CKyle, that's helpful. Also, I had thought about doing the suspending "office" style ceiling but I really just hate the look of those things... I'm just going to have to break down and get someone out here to look at these trusses and see what they can hold.

 

[blakjak220]

And just FYI, I called and talked to the manufacturer of the trusses, he said they were rated from engineering for either drywall or plywood sheathing, insulation, as well as many lights as I would reasonably want. So I think I'm just going to start working on a solution to the "rigged" trusses towards the front of the building so that i can retain as close to the original strength as possible and just have a 12'6" ceiling height. Maybe make a loft on one end for some extra storage.

 

[NUTTSGT]

Definitely more worried about cooling than heating.... keeping the air dehumidified is the other top priority so my tools won't keep rusting away. It was so hot and humid here last summer (my shop was in the uncooled garage) that I just gave up for about a solid month. So hot I was dripping wet after about 2 mins, just not worth it.
The only obstacle to just making the ceiling 12 foot is the previous owner "reengineered" the first 12 joists in order to install an overhead door. Undoing his disaster is going to be a real chore.

Simply fully insulating that space will make a difference in temperature swing changes. That alone will help keep the humidity down and tools from rusting.

How bad did the previous owner screw up those trusses ?

And just FYI, I called and talked to the manufacturer of the trusses, he said they were rated from engineering for either drywall or plywood sheathing, insulation, as well as many lights as I would reasonably want. So I think I'm just going to start working on a solution to the "rigged" trusses towards the front of the building so that i can retain as close to the original strength as possible and just have a 12'6" ceiling height. Maybe make a loft on one end for some extra storage.

After you get the trusses fixed, get it insulated and put a ceiling up. You might want to look at using some ribbed metal siding. It's pretty light weight, goes up easily especially with the help of a friend and a drywall lift. The only issue is that you'd have to make an extension for the lift as they only go up about 11.5 feet.

Have you seen any of the threads on overhead storage ? There's been more than one guy has built it above his overhead door.

 

[blakjak220]

This is how he raised the ceiling height in order to put in the garage door. I'm planning on removing the overhead door so I'll have to fix all that before sheathing the ceiling. I'll check out the overhead storage threads and see what I can find.

 

[NUTTSGT]

Since all the truss plate are installed, they look like they may have been manufactured like that. I'd snap a few more pics and make a trip down to that truss company, if they are just down the road. Inquire with them to see if they have a build/spec sheet on them.

 

[blakjak220]

Yeah the plates do look like they were pressed on rather than beat on with a hammer..... They're still perfectly flat and don't have any dents in them. So Maybe they were made like that from the factory. The guy I talked to said if they were plated and not nailed together that they would def hold ceiling material and lights at a bare minimum. The ceiling may look a little funny but I'm just gonna come up with some way of sheathing around all of it.