Center support beam?

[kojo]

How's it going ya'll, I'm fixing to start building a 40'x20' open pole barn and was wondering about a couple of things. 1st off, I haven't checked all the lumber yards, actually all but 2 i have checked, and can't find anything longer than 16'. If I can't get 20' long boards, I was gonna get 12' long and lap them together for the joist. I'm making it a sloped flat roof. If I lap them together, do I need a center support beam? Next question, If I were to luck up and get 20' long 2x8, would I need a center support beam or could I step up to 2x10 and not worry about the center support beam(providing I can get'em)? I'm going with a metal roof, so there won't be that much weight on it. I was also wanting to go 24" centers. I appreciate any help and advice ya'll can give me on this. Thanks.

 

[EddieWalker]

Do not try to lap together your boards.

You can get boards up to 24 ft long at most lumber yards. I go to McCoys to get mine. According to the span tables I just looked up, it is possible to get get 10 and 20 psf ratings with certain 2x10's and 2x12's. You need to know what type of wood you are buying and then do a search under span tables to figure out your distance and spacing.

Does it snow where are located?

Why not just buy or build trusses?

Eddie

 

[dfkrug]

What about a steel I-beam, KOJO?

My workshop building uses one that is 30ft long and about 12" in depth. You will find
that they are less costly and lighter than equivalent-strength wood members, including
engineered lumber.

You can also attach wood nailers to the top or bottom flanges with a Ramset-type
PAT, if you keep the flange thickness below a quarter inch.

A ridge beam will give you the head space for a ceiling hoist and trolley. I love mine.

 

[Egon]

Buy trusses.

 

[franklin2]

I vote trusses too. Look around, sometimes people order floor trusses and they end up wrong. You may find some a yard needs to get rid of. You might have to adjust your dimensions a little bit if you get a deal on some but that's part of saving money.

 

[kojo]

Thanks for the replies guys, I don't have to worry about snow here, the most we'll get is 2-3", last winter we didn't get any. Boards are gonna be treated southern pine. As for the trusses, I'm gonna be mainly doing this by myself so I figured the sloped flat roof would be easier on me than the trusses would be. And I don't know much about the steel beams. I was hoping I might be able to find 20' long boards and also hoping I wouldn't need a center support beam. I'm gonna call a couple more places tomorrow and see if they have them. There's not gonna be too much weight on her accept the metal or tin roofing. I hate to go the lapping route, because they would definitely need some center support. Thanks again guys.

 

[Egon]

You want yo make it easier on yourself? Buy trusses.

 

[Budweiser John]

You want yo make it easier on yourself? Buy trusses.

Have you considered using I joists? For solo construction the're great. Light and EZ to cut and handle.
A yard caring TJI joists will usually have a computer program to take all the guess work out of span depth and joist spacing.

 

[HCJtractor]

I'm not a builder, but why treated? They are extremely heavy and not necessary for roofing members.

 

[s219]

I'm not a builder, but why treated? They are extremely heavy and not necessary for roofing members.

Agreed, and if using a metal roof it adds all sorts of issues, from requiring hot-dipped galvanized roofing screws to needing a barrier between purlins and metal. I had to use pressure treated wood for a pier boathouse roof due to the wet location, and it was a pain. If you're on land then by all means you should use standard lumber.