roof truss question

[Tom Daniels]

Transforming an old pole barn to my wood shop. The roof trusses were set 8ft on center with 2x4 pulins. I want to to put in a ceiling (metal because it is light) and thought I would take 2x4s and mount them perpendicular to the roof trusses bottom stringer. Any other ideas?

[Paul Greathouse]

Placing the 2x4's perpendicular to the trusses is the way to go. If you want to get by with an even lighter ceiling you could use vinyl soffit instead of the metal.

[Brian Effinger]

I too think it is OK, and you could use either metal or vinyl with purlins at 24" c.c. If you were a little nervous about it, get in touch with a local lumber yard that supplies trusses and talk to someone there.

[Lee Koepke]

8' oc spacing isnt usually designed to support too much. and an 8' span for 2x4s is kinda stretching it, in my opinion.

would it be too difficult to add more trusses ???

[Ray Klear]

MIne are 10' ft on center. I'm going to use metal studs cut and screwed to the top of the truss chord. Flat side up. Then use double sided tape and lay foil faced Styrofoam on top. Did some testing and the double sided tape holds the foam pretty tight. SO Far All in all its pretty light and get some insulation to boot. And the foam is flame resistant.

[Tom Daniels]

Thanks for the input. I do some light construction on the side. I haven't come across this one before. My one issue is that I live in NW Wisconsin so I have to insulate well or I'll be battling the cold. I am interested in the idea of silver insulation. Good relective properties. If you think of any others let me know.

[Jason Beam]

I am doing this RIGHT now ... my garage was done oddly. In from the front about 10 feet, they started trusses - every 4' (roughly) - that were scabbed on to the pre-existing rafters (24" OC). The ceiling is a little low and the garage door had an opener so that's why they didn't put trusses over the garage door.

I worked with a contractor and he did the calculations to ensure I did things correctly. I took out the opener and added a new truss 4' away from the existing ones. If the door wouldn't have hit it, I would have put in a second truss 4' away as well.

Then, my contractor told me to put "Tweeners" between each truss (studs, perpendicular to the run of the studs) attached to the bottom chords with joist hangers. He did some math and said that 24" OC would support 1/2" drywall and up to R19 insulation if I wanted it. The span of the tweeners is very important and I agree that 8' would be too far even for closer spacing.

I'd personally scab on some trusses if you can - 4' apart at a minimum seems wisest - though I'm not an expert. It's just what I have going

[Tom Daniels]

thanks guys. The length of the shed would require 4 more rafters if I were to make them 4 ft on center. I think that's what I'm going to do. I really appreciate the help. If anyone has other ideas please post it. I've gotten a lot of ideas from the couple posted here.

[Neal McCormick]

The trusses in my pole barn are also 8 feet apart. My floor is a 4 inch slab of concrete. When you add the trusses, will the floor support the additional weight of roof or are the added trusses not structural (supporting the roof) but only intended to support a ceiling and insulation? Would the floor need to be opened and a "footer" created to support the new beams and trusses?

[Todd Crow]

I helped my brother build his workshop. We did exactly what you originally proposed. Our trusts were 8' on center, 44' span. We placed 2x4s 2' on center in between the trusts and used 13" of fiberglass insulation (R38) in the ceiling. We then screwed pole barn steel to the 2x4s to make the ceiling.

We are in east central MN. Here are the complete pics of construction

If your concerned about the load the trusts can take you should consult a building engineer. We can only guess to the side of your trusts.

Here is my brothers installing the ceiling purlins and I am on the roof installing roof purlins.




Here my brother and I are installing the ceiling steel. A neighbor is running the lift.

[Thom Sturgill]

Generally there is a stringer that ties the tops of the poles together that the trusses set on. You may need to double it up, but depending on the span you should be able to lay 2-by ceiling joists parallel between the trusses and add stiffners. Lumber size would depend on the span, and there are tables available on the internet to help you size the members based on span and load (in case you decide to put in a loft). A lot of house ceilings are just run on 2x4s.

If you were going to run strapping perpendicular to the trusses then you may need to stiffen the trusses, and I would recommend getting someone to check that out. I would worry about deflection if the 2x was laid flat.