build in enclosed space

[unkamort]

Howdy! I'd like some opinions about hanging 2x4 rafters between my roof trusses to support the weight of sheet rock. The object here is to add a second floor living space inside my garage. The building is of pole barn construction, and measures at 60'x80' with 16' ceilings. The actual size of the enclosed space on the second floor would be around 30'x60'. I know the trusses are designed to carry weight from above, but is there any danger to adding weight to the bottom beams?

 

[matt_i]

Re: build in encolsed space

So in (48" x 96" =) 32sf of 1/2" thick drywall it weighs roughly 50 lbs. So about 1.5 lb/sf. I don't think that would be any problem with a standard engineered truss. Obviously the wood has to be supported too but I'd guess its roughly about equivalent if not less.

 

[readhead]

Re: build in encolsed space

Need more info. How is the floor being built? At 16' will you have 8' downstairs and 7' upstairs? I am not real clear on the plan here.

 

[Toolfool]

Re: build in encolsed space

If I understand your question correctly, the answer is YES, there can be catastrophic damage done by adding weight to the bottom cord of trusses that are not engineered to support that weight.

 

[sledneck32!]

Re: build in encolsed space

What he said. They gotta be engineered for the second story. Whether engineered or not, they would probably hold the sheetrock up.... But i dont recommend doing that without knowing for sure. Where is can get real dicey is when u start hauling **** upstairs for storage, and then periodically adding a live load.

Check the engineering

Sent from my LG-H811 using Tapatalk

 

[unkamort]

Re: build in encolsed space

The second floor is supported on 2x12 stock, with 1/2" sheathing. So I gave up some head room on both floors in favor of a solid second floor. The lower floor wall stud length is 87.5" + upper/lower plates. This is why I had hoped to tuck the upper floor rafters between the trusses. I could frame the upper floor walls independent of the truss, but would have to give up that 4".

 

[Toolfool]

So you're only talking about adding framing and drywall to create a ceiling on the bottom of the trusses ? That should be fine.

 

[CNGsaves]

Re: build in encolsed space

The second floor is supported on 2x12 stock, with 1/2" sheathing. So I gave up some head room on both floors in favor of a solid second floor. The lower floor wall stud length is 87.5" + upper/lower plates. This is why I had hoped to tuck the upper floor rafters between the trusses. I could frame the upper floor walls independent of the truss, but would have to give up that 4".

Let's see some Pics . . . . . 30' x 60' living space is WHOLE house for lots of folks !!

Where did you get 30 ft long 2x12's ??? Or are those LVL's ??

What is plan for heating/cooling on upper floor ??

 

[Kevin54]

Use 1x3 strapping and lightweight drywall in 12' sheets

 

[unkamort]

Re: build in encolsed space

Let's see some Pics . . . . . 30' x 60' living space is WHOLE house for lots of folks !!



These photos may not show you much. The lower floor will house an office space, parts room, tool room and general storage room. 2x12's were chosen because two of the rooms have a 16' rafter (or floor joist for the second floor) span. The stud walls below are 2x6 and have a fabricated post every 8'.
As far as heat/cool...I had thought of the same type of unit found in motel rooms for the bed rooms, and a wall furnace with separate AC unit for the main living space. As you can see by the rather crude floor plans a lot of space will be dedicated a large interior deck, which will not be enclosed.

 

[unkamort]

3 day BTT... The crowd seems pretty evenly divided on whether this might be a good idea. I found these old pix of the actual trusses from 24AUG13. I tried to get hold of the guy that did his work for his pinion but couldn't make contact. I'm not trying to jump off into this tomorrow... but I like to think ahead.

 

[theoldwizard1]

2x12 joists don't sound adequate for spanning 30'. It is also difficult to purchase 30' long lumber unless it is Douglass Fir which is expensive.

If you are really going to span 30', you need wooden I-joist or a parallel cord truss. Some parallel chord trusses do not have to have the bottom chord rest on the studs. The top chord can be built longer and then it can rest on the studs. Check with manufacturer.

I also think you are mixing up your terminology when it comes to roof trusses.

 

[wkearney99]

If it was a permitted job it should have plans on file, and those should include information on the engineer that planned the trusses. Seems like it'd be smart to follow that paper trail to get (pay for) a professional response. Otherwise you risk pulling the structure down, if not right away, then later after everyone's forgotten it's more of a house of cards, than a properly engineered structure. Just sayin'....

Otherwise I'd think you'd be better off planning on building a frame within the structure to act as a platform to hold the second level. That'd require proper footings under whatever sort of posts are used.

It's all about how the loads are spread back down to the ground. From the looks of that framing during construction I wouldn't think it's engineered to handle anything more than the weight of it's own materials and whatever's typical for snow loads in your area.

Not trying to take a perfectionist angle here, just pointing out that whenever trusses are involved they're generally NOT engineered to handle anything more than what's already there.

 

[unkamort]

Thanks for your reply. I agree that I'm in over my depth here. I got up on the second level today and found 7'7" from the unfinished floor to the bottom of the truss. Subtract an inch for the carpet... This was the reason for wanting to put stringers between the trusses to support the dry wall on the ceiling on the second floor. Now I'm wondering what if I used aluminum studs to keep the weight down. I enclosed some additional pix... plainly I'm not there yet. Also some rough shots of the parts and tool rooms, and my new LED lights. Should be easy to get some extra work in evening times!

 

[unkamort]

Didn't get the pix in...

 

[wkearney99]

Oh, I get what you're after now, you're only talking about hanging drywall UNDER the trusses. Is that correct?

The floor is for this second level is going to rest on those interior walls, yes? What sort of joists are you going to be using across those walls to support that floor for the second level?

You might also need to consider there's likely going to be a fair bit of movement between the interior structure and the roof trusses. As in, the building may shift enough with wind/weather/temp changes to present problems with the joints where the drywall on the ceiling meets the walls.

I'm still inclined to think of this is more of a building-within-a-building. Where the interior spaces you're constructing are pretty much free-standing, independent of the rest of that building.

 

[theoldwizard1]

Howdy! I'd like some opinions about hanging 2x4 rafters between my roof trusses to support the weight of sheet rock.

Glad you posted those pictures ! I was totally lost !!

Those trusses looked to be spaced 8' apart. Hang 2x4 between the bottom chords using Simson Strong Tie joist hangers. Space them 16" O.C. apart.

 

[cat06]

you would be better to talk to a truss builder, not even the one that built your trusses, any should be able to answer your questions

 

[unkamort]

Oh, I get what you're after now, you're only talking about hanging drywall UNDER the trusses. Is that correct?

The floor is for this second level is going to rest on those interior walls, yes? What sort of joists are you going to be using across those walls to support that floor for the second level?
A: They are 2x12 because of the span

You might also need to consider there's likely going to be a fair bit of movement between the interior structure and the roof trusses. As in, the building may shift enough with wind/weather/temp changes to present problems with the joints where the drywall on the ceiling meets the walls.
A: I hadn't considered that, and wind can be a factor here in the spring


I'm still inclined to think of this is more of a building-within-a-building. Where the interior spaces you're constructing are pretty much free-standing, independent of the rest of that building.

A: Well only up to a point. Around the perimeter of the enclosed (1st floor) space I built stud walls between the 'poles' and they are connected. I will use the same system on the second floor perimeter. I was thinking that if I did ceiling first I could use interior walls to brace up some of the material that I added.

 

[rayra]

Re: build in encolsed space

If I understand your question correctly, the answer is YES, there can be catastrophic damage done by adding weight to the bottom cord of trusses that are not engineered to support that weight.

This. Drywall adds a LOT of weight in a hurry. If you just want a skin and the drywall won't be supporting anything above it, consider 1/4" drywall, or even a drop ceiling with lightweight panels or even a tin ceiling.


Another way is double your trusses. Sister matching boards to them.

 

[FordTruckWench]

Re: build in encolsed space

This is why I had hoped to tuck the upper floor rafters between the trusses. I could frame the upper floor walls independent of the truss, but would have to give up that 4".

I think you mean ceiling joists.

How about framing the upstairs walls with the top of the top plate an inch or two* below the trusses. Then add ceiling joists parallel to the trusses, but supported by the walls. Hang the drywall from these ceiling joists. This way the ceiling and the trusses are independent of each other, and you only lose the inch or two.

* It would be nice if you could find out deflection specs for your trusses when they have the "worst case" design load. Keep your interior work below this.