Need Advice On Installing OSB To Garage Trusses

[msmit62]

Attached are three pictures of the trusses inside my 1970's garage. I'm currently working on wiring it and soon will be installing a ceiling. Can anyone tell me whether or not these trusses will support 7/16 OSB? I need to determine my intended ceiling thickness before installing receptacle boxes for the lights.

In my last garage I installed lauan plywood but it soon warped and I was never happy with it. This time I'm using something thicker.

Someone told me if I was concerned about weight I could use 1/4" OSB but 7/16" was probably less money...I'm not sure if that is true or not.

Thanks in advance.

 

[mike93lx]

No one can give you a real weight rating for site built trusses, although those look like they were at least well done. Big plates and lots of fasteners.

That said, if it can't handle about 1 lb per square foot, you have bigger problems

 

[OccupantRJ]

My shop has standard fink trusses on 24” centers with 7/16” osb screwed in place.The joints were aligned and beveled on the edges to look like 4x8 ceiling tiles. I used extra scabs in the attic on the linear joints to keep edges aligned over time. The joints were spaced 1/16”and caulked after installation for thermal expansion purposes.

 

[Innovate1]

OSB is heavy. Sheetrock is too. No idea if they will support it but there are lighter options. For my shop I used ribbed steel panels like used for shop/barn roofs. Some places make a thinner version for ceilings. Very light and quick to put up. You do have to deal with the ribs when mounting stuff but electric boxes can be put in the flats between ribs.

 

[msmit62]

A friend at my church sells and installs the metal panels and I actually gave some thought to going that route but I was hung up on how to mount receptacle boxes (you're saying one will fit between the ribs) and also OSB or plywood would give me the flexibility to screw things to the ceiling if desired. Also, mine are on 24" centers.

 

[OccupantRJ]

OSB is heavy. Sheetrock is too. No idea if they will support it but there are lighter options. For my shop I used ribbed steel panels like used for shop/barn roofs. Some places make a thinner version for ceilings. Very light and quick to put up. You do have to deal with the ribs when mounting stuff but electric boxes can be put in the flats between ribs.

There is a roof panel production facility a couple of miles from my shop. They roll 26 and 29 gage panels, with the 29 being the lighter.

 

[PCustoms]

My shop has standard trusses

What is a "standard truss"?

and also OSB or plywood would give me the flexibility to screw things to the ceiling if desired.

If you're worried about the trusses ability to support ceiling material, I sure wouldn't be considering screwing anything to it after the fact...

The trusses do look well built, the only thing that throws me off is the paint under each gusset

 

[Innovate1]

What is a "standard truss"?


If you're worried about the trust disability to support ceiling material, I sure wouldn't be considering screwing anything to it after the fact...

The trusses do look well built, the only thing that throws me off is the paint under each gusset

I'm thinking that is glue. They really slathered it on apparently.

 

[OccupantRJ]

A friend at my church sells and installs the metal panels and I actually gave some thought to going that route but I was hung up on how to mount receptacle boxes (you're saying one will fit between the ribs) and also OSB or plywood would give me the flexibility to screw things to the ceiling if desired. Also, mine are on 24" centers.

If old work electrical boxes are used the holes can be cut in the middle of the flat area. The boxes would then attach to the panel. The qualified electricians will have to be the ones to quote code on this method.

 

[mike93lx]

The trusses do look well built, the only thing that throws me off is the paint under each gusset

I assumed it is a glue

 

[PCustoms]

I'm thinking that is glue. They really slathered it on apparently.

I assumed it is a glue

Maybe. You think after the first couple the guy would have realized he didn't need 2' of glue for 1' gussets

 

[OccupantRJ]

What is a "standard truss"?


If you're worried about the trust disability to support ceiling material, I sure wouldn't be considering screwing anything to it after the fact...

The trusses do look well built, the only thing that throws me off is the paint under each gusset

What is a “trust”?

 

[mike93lx]

Maybe. You think after the first couple the guy would have realized he didn't need 2' of glue for 1' gussets

The man had a job and he did it

 

[PCustoms]

What is a “trust”?

Trust disability= trusses ability+******* autocorrect.

No way I typed disability in that post lol

 

[PCustoms]

Back to the OP, I'd strap that and hang 1/2" or 3/8" light drywall.

BUT

Im not sure I'd attempt any insulation on top of that. Any plans there?

 

[msmit62]

I had the same thoughts regarding the "paint" but I think it is glue. I definitely plan on insulating the walls and ceiling. I was probably going to staple in R-30 batts.

 

[OccupantRJ]

Looking at my pictures with the hoist monorail and all the various reels attached to the ceiling, mine should have caved in many moons ago if it was going to! 12 years in use and counting. The trusses more directly involved in the trough area of the hoist have been heavily reinforced basically to act as a wooden bridge lattice structure for additional support.

 

[Innovate1]

If old work electrical boxes are used the holes can be cut in the middle of the flat area. The boxes would then attach to the panel. The qualified electricians will have to be the ones to quote code on this method.

Now that I think about this a bit more I just made small holes for the cables to lights with the electrical connections inside the light fixtures. I did put one outlet on the ceiling for a cord reel and don't remember exactly what I did for that - I think I put blocking behind it or maybe just put it where I could screw into the truss - I used a surface mount box for that.

If you are insulating then air sealing of the outside edge of the tin is kind of a pain. The edge goes into a J channel that has lots of leakage so I went around and caulked it.

 

[msmit62]

A friend of mine is an electrician and has wired many garages with the corrugated metal ceiling. He said he punches through the metal and makes the connection inside the light. I'm concerned about the holes in the metal cutting through the wire insulation so he must have used some type of bushing. so, when I read that you put boxes in the low area I was interested to learn more. Either way, I am still leaning towards a wood ceiling. I do like that I wouldn't have to paint the metal, though.

 

[Innovate1]

A friend of mine is an electrician and has wired many garages with the corrugated metal ceiling. He said he punches through the metal and makes the connection inside the light. I'm concerned about the holes in the metal cutting through the wire insulation so he must have used some type of bushing. so, when I read that you put boxes in the low area I was interested to learn more. Either way, I am still leaning towards a wood ceiling. I do like that I wouldn't have to paint the metal, though.

Yep. They make snap in bushings that are easy to put in to cover the sharp edge.

 

[Firebrick43]

A friend of mine is an electrician and has wired many garages with the corrugated metal ceiling. He said he punches through the metal and makes the connection inside the light. I'm concerned about the holes in the metal cutting through the wire insulation so he must have used some type of bushing. so, when I read that you put boxes in the low area I was interested to learn more. Either way, I am still leaning towards a wood ceiling. I do like that I wouldn't have to paint the metal, though.

I usually just put a 2x4 across where I want a light but I don’t hang a box until I am ready to hang the sheet that will go over it. It allows me to measure from the last rib already hung and place the box so it will be on a flat between ribs. I then just measure the R panel and mark out where the box needs to be cut out. Then drill a hole with a step drill and cut out to the line with aviation snips.

 

[Fav Onefour]

A friend at my church sells and installs the metal panels and I actually gave some thought to going that route but I was hung up on how to mount receptacle boxes (you're saying one will fit between the ribs) and also OSB or plywood would give me the flexibility to screw things to the ceiling if desired. Also, mine are on 24" centers.

I'm glad you confirmed the spacing. In the pictures, it was hard to verify. The trusses almost look like they are built to snow load standards although the spacing is wider.
How wet does it get in the garage during winter? That would be my biggest concern with OSB.

 

[msmit62]

Once insulated and my hanging furnace installed, I'm hoping to keep the interior temp slightly above freezing so the cars thaw during the winter. I have a new sloped floor with a drain so the water shouldn't collect in one spot. I also plan on priming and painting the OSB. I could use bathroom ceiling paint (ie waterproof) versus regular latex if you think that would be a good idea.

 

[jkuro]

What is a "standard truss"?

A standard truss is different than a non-standard truss.

 

[racecougar]

Liner panel and surface mount EMT. Land your boxes on the flats between ribs. Easy peasy, reliable, light weight, and don't have to paint.

I can't say that I have any pics that focus specifically on the EMT installation, so these will have to do.

 

[Fav Onefour]

Once insulated and my hanging furnace installed, I'm hoping to keep the interior temp slightly above freezing so the cars thaw during the winter. I have a new sloped floor with a drain so the water shouldn't collect in one spot. I also plan on priming and painting the OSB. I could use bathroom ceiling paint (ie waterproof) versus regular latex if you think that would be a good idea.

You are heating the space? That's a big factor too.
I can't see venting. Are you planning on insulation? Those are factors in cold climates. The hot/cold transition layer will form condensation.

Honestly, if you're heating the space, it should have proper venting and a vapor barrier. The OSB wouldn't take such a moisture load...... You could get by with pretty basic paint.

 

[Jgaz]

My shop has standard fink trusses on 24” centers with 7/16” osb screwed in place.The joints were aligned and beveled on the edges to look like 4x8 ceiling tiles. I used extra scabs in the attic on the linear joints to keep edges aligned over time. The joints were spaced 1/16”and caulked after installation for thermal expansion purposes.

I like the beveled edge

 

[AC-WC]

I'm in the steel liner panel group. 'Light' weight, no drywall dust, no repainting, no sag, relative ease for install, gloss for light reflectance. Just my opinion but I've never liked OSB texture even when painted.

 

[Hank11]

OSB will be a hellish thing to hang and finish. And if you’ll have humidity it is a poor choice of material. Go with metal. Friends don’t let friends use OSB.

 

[cpakalolo]

Attached are three pictures of the trusses inside my 1970's garage. I'm currently working on wiring it and soon will be installing a ceiling. Can anyone tell me whether or not these trusses will support 7/16 OSB? I need to determine my intended ceiling thickness before installing receptacle boxes for the lights.

In my last garage I installed lauan plywood but it soon warped and I was never happy with it. This time I'm using something thicker.

Someone told me if I was concerned about weight I could use 1/4" OSB but 7/16" was probably less money...I'm not sure if that is true or not.

Thanks in advance.

The building was built to a certain standard whatever that may be. The sheathing layers are always assumed in a truss schedule. The weight is standardized as the same as fire-code 5/8" sheetrock. The 7/16" OSB will be just fine. If you want to go lightweight, you could do exterior sheet metal in any color you like. The metal goes up faster too.

 

[RoadBeater]

I did 1/4” OSB in my warehouse, had to use pine furring strips to help keep it from sagging, not recommended. I went metal siding in my pole barn.

 

[PCustoms]

I did 1/4” OSB in my warehouse, had to use pine furring strips to help keep it from sagging, not recommended. I went metal siding in my pole barn.

I've never seen 1/4" OSB, but I can see how that wouldn't work well...

 

[mike93lx]

I've never seen 1/4" OSB, but I can see how that wouldn't work well...

Same here. Sounds like cardboard with more weight

 

[PCustoms]

Same here. Sounds like cardboard with more weight

Previous owner had paneled portions of the basement in some sort of particle board/cardboard/vinyl garbage. Had 2-3 types of fasteners in each panel, I assume he kept coming back to tack it in place.

Was a PITA to rip out as you'd get under a piece and a little 12" chunk would tear off. Ended up cutting around the edges and ripping them out, studs and all.

 

[CraigStu]

looks to me like those trusses are built from 2x4s. Also the pitch of the roof is pretty shallow so not a real strong triangle. In a previous house I had an extra bay added on w/ similar trusses. While it was being built I cut a piece of 1/2" osb in half lengthwise and set the pieces in the center of the trusses. The framing inspector saw them and asked for the truss drawings. He wanted to see if they were rated for storage. The builder had the drawings but wasn't there that day so we had to schedule another inspection the next week. Turns out they were not storage rated trusses. Yeah the guy was being a d--k and the next inspector says all I see is a catwalk so you can get to your wiring. He signed off on the permit but I haven't forgotten that the first inspector was technically correct. I think you should do metal and light weight insulation.

 

[strutaeng]

7/16 osb for ceiling will not be a problem for those.

Is that garage attached to uour house? I wouldn't be surprised if the same trusses carry on into the home that has 1/2 drywall ceiling with compare weight, or close enough within a few ounces.

 

[mike93lx]

looks to me like those trusses are built from 2x4s. Also the pitch of the roof is pretty shallow so not a real strong triangle.

My last house had 2x4 trusses on a 28ft span in New England. Steeper pitch than that (6:12) but a significant snow load.

 

[PCustoms]

My last house had 2x4 trusses on a 28ft span in New England. Steeper pitch than that (6:12) but a significant snow load.

I've got 2x4, IIRC 28' span plus the 8' cantilever and something low like 3/12 of the saltbox side. The plywood decking is starting to show some dips, but I was just in the attic last week and trusses are fine.

Probably should start planning for a new roof

 

[mike93lx]

Probably should start planning for a new roof

Ice and water on all the things.

My roof was done right before moving in and they went 9' up with it, but I always swore if I was doing a roof in New England, the whole damn thing would be covered.

 

[PCustoms]

Ice and water on all the things.

My roof was done right before moving in and they went 9' up with it, but I always swore if I was doing a roof in New England, the whole damn thing would be covered.

House was built in '85, has been re-shingled once, doubt there is anything under it. I used some snap lock panels last summer that I like, but honestly house is probably worth screw down, which I don't want to do (bad prior experiences screwing one down).

I should start a thread, my ventilation is a little odd too