Building a Beam

jsbeckton

I want to build a gable roof over my deck (comming out from house ~ 15') with a ledger at the house and a beam out at the yard. I do not want to have supporting posts between the ledger and beam. I was thinking that I would use a beam on each side made of double 2x10s but looking at the 2009 IRC, table R502.5(2) for one floor it looks like the max span for this beam would only be 7'?

That doesn't seem like a very far distance for a 4x10 to span (foor a roof load). Am I reading the table correctly? What you recommend I do to span this distance without a post?

dtsman

Are you talking about a ridge beam?

If it is non-structural that spec doesn't apply. For a gable roof, you don't even have to have a ridge beam. A single 2x10 will be fine because it will be supported every 16" or 24" depending on rafter spacing. The walls will bear the force of spreading so you will need cross pieces a couple of feet down from the ridge to keep the rafters from pushing the walls out. Creating a truss design.


Bo

Remember,
If the women don't find you handsome,
they should at least find you handy.
(Red Green)

jsbeckton

Not the ridge beam, the side beams (top plates?) that run parallel to the ridge beam that would be the top of the wall where the rafters come down, only i don't have a wall and hence do not want posts along that span.

dtsman

Span tables
http://napasolanoicc.org/Links/IBCSp...apterFinal.pdf


Off the record, you wil probably be OK if you glue 1/2" plywood between them and take it up to 12" width wood and use a strong wood like fir, not the cheap pine from HD. Used this process for years over 2 car garages without a second story above. Although, I believe the new standard is LVL beams because they never deflect.

Stay with the 2x10's and just add a support halfway. It want look as bad as you think.

Found this that shows a similar situation:
http://harbourtownllc.com/renovation_101_Part_3.html


Good Luck,
Bo

Remember,
If the women don't find you handsome,
they should at least find you handy.
(Red Green)

jsbeckton

dtsman,

Thanks for the help.

That is very close to my appliction, only this is just a span w/o a garage door. The reason that I do not want to add a support is becuse the deck will extend beyond the roof so there would be a post right in the middle of the deck (kind of like they wanted a 2 car garage opening instead of 2 seperate openings with a support in the middle).

I guess my next question would be, in IBC Table 2306.9.5 it shows the max spans for dimentional lumber but not LVL. Are there similar tables for LVL (since I thought it was supposed to be even more consistant then dim. lumber)?

This is the closest that I could find but it is not clear to me how to read it: http://www.parr.com/PDFs/LP%20LVL%201.9E.pdf

Thanks again,
Josh