Expert: Richard Taylor, AIA - 4/22/2008

Question
Richard, I'm planning on putting a 16 X 16 covered deck on my house located in Penna.  I was planning on building a gabled roof with just roof rafters and no ceiling joists.  What I would like to know is how do I tie in the ridge beam to the existing structure.  I have a 2 story house.  Should the ridge beam go through the house sheathing to be attached.  If so how should that be framed.  I did not want to use a roof ledger and support post on the outside of the house.  Any information you can provide will be appreciated.
Thanks.

Answer
Jim - thanks for your question!

The end of the ridge beam that bears on the exterior wall of the house will carry 1/2 the load of the entire roof; for a 16' long ridge that's approximately 2500 lbs. including the potential snow load!

You can hang the beam end from the sheathing using a beam hanger (I'd look at www.strongtie.com for hangers) but sheathing alone won't carry that load.  You've got to have structure behind it, and you've got to trace the load down to the foundation.

That means you'll need to open up the wall and install proper structure to bear continuously down the wall - including any headers over openings - until you reach the foundation.  Then you can re-sheath the wall and attach the hanger and beam to the new bearing structure through the sheathing.  Sounds like a lot of work, but you're going to be removing siding anyway to flash the roof, right?

The sizes of these new members is something you'll have to have done on site to meet local codes.

If it's a vaulted ceiling you're after, you might consider using scissors trusses instead of rafters and a ridge beam.  The overall cost is about the same, they're less work to install, and you won't have a ridge beam to worry about - all the bearing is on the sidewalls.

Hope this helps,

Richard Taylor, AIA
www.rtastudio.com
www.rtaplans.com