ceiling load

[smithcm72]

i'm in the process of putting a living area in part of a pole barn. the trusses were designed for a ceiling load (10lb bottom cord dead load). but they are on 8' centers. should i run 2x4 or 2x6 between trusses? on what centers? should i use metal hangers? they will have to support drywall & blown in insulation. i don't want the ceiling to sag. any advise or links to calculating tables would be appreciated. thanks

[Richard A Hetzel]

Any framing members applied flat to the bottom chords of the trusses will sag over 8 feet. It wouldn't matter if they were 2x4 or 2x12, the key dimension is the 1 1/2 inch thickness, and that's just not sufficient. It might be better to forget the trusses and use ceiling joists which span from wall to wall, supported by the walls.

[smithcm72]

i would not run the 2x flat under the bottom cord. i would run them on edge between the truss bottom cords, possible on hangers. the trusses were made for a ceiling load. my worry is will the 2x sag between trusses with the weight of the drywall & insulation.

[Don_P]

2x4's @16" ctrs are sufficient as ceiling joists for this span in the codebook.

[Richard A Hetzel]

But not 2x4's on the flat...the code table is for 2x4's upright.

[Rich]

I don't see where the OP is suggesting running them flat.

[smithcm72]

great. 2x4's @ 16". should i use hangers to attach them to bottom cord of truss.

thanks for the feed back.

[Richard A Hetzel]

How else would you attach 2x4's to bottom chords of trusses? There are no hangers that I know of designed for 2x4 joists attaching to what are probably 2x4 or 2x6 chords.

[Joe Carola]

How else would you attach 2x4's to bottom chords of trusses? There are no hangers that I know of designed for 2x4 joists attaching to what are probably 2x4 or 2x6 chords.

http://www.strongtie.com/products/connectors/hangertables/face_ss-df1.asp

[Don_P]

Yup, hanger them. This is one type;
PF24 is the smallest for a 2x4 onto a 2x4, although I imagine your bottom chord is more than a 2x4. I like a top hung if possible for something like this. The "products", and then "connectors" tabs at the top of the page has the whole catalog.
http://strongtie.com/ftp/catalogs/c-2008/C-2008-p076.pdf


Edit, I stopped typing to stuff my face while Joe was posting... What he said. :)

[Richard A Hetzel]

Well, now I know of them