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Raise High the Ceiling Beam Carpenters.

IronDog's picture

Forgive me for the cheap J.D. Salinger pun.

But, here is the question!

Doing a two story addition and the client would like the ceiling joists for the second floor ceiling raised as high as possible up the rafters.

I have no idea how high they can go and am having a hard time finding an engineer who wants to deal with a penny ante question like that.

I'm sure part of the answer lies in how the joist and rafter are connected. ( I'm thinking plywood gussets and glue/nail).

The pitch is about 6/12.

23' span.

No big loads. Baltimore location so rare snow loads and regular shingle roof.

Any thoughts are greatly appreciated as always!


You Don't Know. You Don't Want to Know. You Aren't Going to Know.

(post #90505, reply #1 of 3)

Use a structural ridge beam and you can go as high as you/they want but you should pick something that looks good proportionally too.

Without a structural ridge, the old rule of thumb (rules of thumb being what they are) was a third of the way up the rafter, which also happens to look pretty decent. How well you fasten them is as critical. They perform not only to hold ceiling up but to keep the walls from spreading so the tension is on the fasteners. three sixteens won't do it.

Excellence is its own reward!



Oh Well,

We did the best we could...

(post #90505, reply #2 of 3)

Thanks for the reply Piffin,

A third of the way up would be just fine in this case.

What do you think of my joist / rafter connection idea of plywood gussets / glue / nail? Or even better I could bolt and glue the gussets.


You Don't Know. You Don't Want to Know. You Aren't Going to Know.

(post #90505, reply #3 of 3)

If you're inclined, you could probably get some tail bearing trusses. That would aleviate you of any design responsibility.

The United States is the only country where it takes more brains to figure your tax than to earn the money to pay it. [Edward J. Gurney]