Can 48" OC truss support drywall?

So I insulated my Garage last winter when I bought my house. I put up plastic sheeting on the ceilling to help hold heat in. I was planning to finish the walls/ceiling soon here with drywall, but realized today that that might not be doable. Not sure on exact measurements but my garage is roughly 30ft wide by 23ft deep. and has ceiling joists (may or may not be correct term) 4ft on center. They also arent even 2x12, I didnt measure them but they arent bigger than 2x10 and they are all 2 boards held together (end to end) by that metal plating that just gets hammed or pressed into them. and then theres a 1x4 running from that section to the roof peak to ad support to them i guess. Can these support drywall?

 

Short answer absolutely no. Horizontal sheetrock needs super support and 48" oc will only catch the edges and midpoint. 16"oc is best, with 24"oc the absolute widest.

 

I know I could just ad 2x4 framing in between to create a surface to screw into but what im wondering is if the weight of the drywall hanging from it is too much for this lightweight construction?

 

We can't see your trusses and don't know if they were engineered for a standard dead load or if they were built by mickey mouse and friends. (The mention of 1x4's doesn't sound promising) Also can't say if adding framing would work for the exact same reason.

 

Trusses 48" OC..... wow. How long are they ?

A picture or two would be helpful. http://www.doityourself.com/forum/el...-pictures.html

 

It all looks professional to me as far as cuts go. (compared to some of the remodeling work inside the house)

But they are just 2x6s 12ft end to end is what you are looking at in the pic. and then theres a few verticle 1x4 or so boards staggered around on every other truss or joist, whichever. Theres been boards up there ever since we moved in and a heavy wooden garage door is hanging off of them which I hope to replace with a steel insulated door before winter

 

Thanks. The picture is very good and shows a lot.

I can't believe the roof sheathing is very solid with that spacing.
What do you get for snow there ?
There doesn't appear to enough support there for much additional loading.

I'll let the pro's respond.

 

The roof is also 2x6 every 24"

 

No way I would add framing and drywall to that. Hope it's a metal roof.

 

We get plenty of snow, I live in southern WI. The roof is shingled. The way it looks with the way the roof supporting 2x6s are tied together at the peak, i imagine they are what carries the load to the wall and all these 2x6s are doing is holding the walls together and not actually supporting the ceiling in any way. I dont know if thats correct or not though

 

I guess the other option I was considering is putting insulation/drywall on the ceiling running up to the peak on the 24" on center boards? Although id lose more heat opening up the ceiling that much

 

The garage doesn't look to be 30 feet wide in the picture.
The trusses do not look engineered, but built on site. As others have stated, you're probably at minimum (strength) already for dead and snow loads in your area, that would have to be determined locally.

Any chance of removing roof entirely and starting over with engineered trusses? This would obviously be costly, but maybe worth it in the long run.

 

The pictures were taken from a random area in about the middle of the garage so your seeing less than half of it the other half is obviously behind me. The wall you see in the pic straight ahead is the side of the garage and front with the door is to the left. Starting over really is out of the question. Really all I want is to help hold in more heat this winter. I dont plan on owning the house more than a few years. Its our first house, we bought it cheap and plan to resell it when we can afford a higher payment.

 

Not a viable option. You would then be trapping all the heat and moisture against your decking. Although somewhat expensive, you may could have closed cell polyisocyanurate sprayed on the rafters and decking as insulation. It is lighter in weight and would give good insulative values.
Do nothing to the current joist setup, as they are not strong enough to hold sheetrock. It amazes me why someone would stick build a roof system, when buying trusses would have probably been much more cost effective and stronger.

 

Maybe ill just double up the plastic and leave the roof unfiinished. Unless I can find some lighter weight paneling to put up there. Thanks guys

 

I'm far from expert in these matters but I don't see any trusses. I see a (more or less) conventionally framed roof with rafters. The horizontal ceiling joists are to prevent the downward load on the roof (rafters) from spreading the walls. That makes those members in tension and therefore the nailing plates on the joists are possibly okay, something that would not be acceptable if there were any downward pull from either a floor above or a ceiling below. The vertical members are of limited value, in my opinion.

What I might consider is full-length joists of a more acceptable height be sistered onto the existing joists. Another possibility would be an engineered cable stay system to hold the walls from spreading and that would relieve the wooden "joists" of that task. The cable stays would have to be sized according to the stresses imposed upon the walls, definitely a job for a structural engineer.

IF that were done then adding additional joists would allow for drywall to be hung. OR a lightweight suspended ceiling could be installed.