I’m looking at a house, old house getting interior remodel, where they want to remove a row of 4×4 post supporting a beam across the ceiling. spans about 15 feet across the ceiling, under the middle of the rafters (follows underneth the ridge of the roof).
in it’s place we would want to put a beam capable of supporting the rafters but only supported at each end of the beam. (existing is supported at each end, plus twice in the middle). other words, we want to get rid of the two supports in the middle of the room.
I know it’s a good idea, and I plan to do so one way or the other…. but i’m curious as to rather it’s a legal requirement to get an engineer to spec the beam?
Another question… I’m trying to help the homeowner plan things out, and we will be obtaining permits for this work. Will the framing, plumbing, electrical inspections happen all at the same time, or sepratley?
located in raleigh, nc.
thanks
Replies
You can spec simple beams with the tables in the code, at least the code where I am (IRC 2003).
A beam with a uniform load across its length, supported at each end is pretty much as simple as it gets.
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one variable here is that the rafter bottoms are spliced together (sistered) in the center of hte room, right over the beam. I dont think there's normaly that much of a load there, but we did get 2 feet of snow here about 5 years ago.
I'll get out the code book and check it out.
thanks.
>>I dont think there's normaly that much of a load there
You said the room is 15' wide. How long is it? Your beam will need to support half of the entire roof load.
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the rafters span about 20 feet one way, 10 the other. (30 feet over all). The front of the roof slopes less than the back.
Right, but what is the length (i.e., the length of the beam).
Also, I must have missed something. What is the overall width (level width, not rafter length) of each "side."
"Let's get crack-a-lackin" --- Adam Carolla
We'd better be careful about the situation because your description is unclear:
remove a row of 4x4 post supporting a beam across the ceiling. spans about 15 feet across the ceiling, under the middle of the rafters (follows underneth the ridge of the roof
OK- what will the beam need to support? From your description I don't know if this the existing beam and posts are supporting the ridge itself (i.e. bearing roof load from rafters on both sides of the ridge) or is just halfing the span of the ceiling joists, and that matters greatly to the design of the beam.
If you get snow load where you are, you'd better get an engineer involved. In my jurisdiction (Ontario), beams beyond 12' free span can't be sized from the tables in the building code, so the building department would want to see an engineer's seal on the sizing. In other places, you can size LVLs etc. for a ridge beam from tables without an engineer involved. If you provide a sketch of the roof framing to clarify the structural situation, people here can help you with some basic information and help you decide what sort of beam to use. That may help you out, because instead of the engineer spec'ing something that is easy for him to calculate, you can have him check the sizing of the beam YOU will find easy to install.