roof ridge beam support
roof ridge beam support
(OP)
I need to frame attic floor roof. Cannot have color ties and no ceiling joists from below to connect roof rafters to resist outward thrust force. I'm using 3-1/2"x 14" LVL ridge beam but unfortunately cannot place support on each end of beam (architect showing open space). What options do I have?






RE: roof ridge beam support
Kinda sketchy solution, but I have done things like this before.
Mike McCann
MMC Engineering
http://mmcengineering.tripod.com
RE: roof ridge beam support
RE: roof ridge beam support
RE: roof ridge beam support
RE: roof ridge beam support
I would also suggest doing it out of steel. This way you will know everything will work.
RE: roof ridge beam support
Garth Dreger PE - AZ Phoenix area
As EOR's we should take the responsibility to design our structures to support the components we allow in our design per that industry standards.
RE: roof ridge beam support
Just model the roof in RISA 3D.
Mike McCann
MMC Engineering
http://mmcengineering.tripod.com
RE: roof ridge beam support
I have an idea for one side of your problem.....
I framed a house once that had a similar situation and we used a steel cranked beam that formed the hip rafter on one side of the house and the valley on the other and landed on the walls.
I think this might work for you here with your valley being the valley of the dormer.
In your case the one side of the ridge could tie to this cranked beam and your ridge could also be a cranked beam that formed the slope of the roof that is above the toilet.
RE: roof ridge beam support
I think I need to do similar what msquared48 suggested, design moment connection for points where ridge beam meets with hip rafters. Simpson Connectors have similar solutions but thickness of the plates is too small, need probably min 7 gauge metal to fabricate these connectors.
RE: roof ridge beam support
If they want a complicated roof framing system that won't allow you to have a ceiling beam to take the ridge reaction then in my opinion they bought a steel beam.
We introduce steel on a lot of our custom homes. Builders out here are used to working with it and I don't think the premium is all that significant compared to the total building cost.
Can you drop the ridge beam so that it doesn't daylight through the dormers and run it long to the cross-walls? Architect would either have to fur the ceiling down, box it, or expose the beam
RE: roof ridge beam support
More I think more I agree that STEEL is the way to go.
RE: roof ridge beam support
That redesign should be extra money in your pocket. Keep the faith!
Mike McCann
MMC Engineering
http://mmcengineering.tripod.com
RE: roof ridge beam support
RE: roof ridge beam support
It might cost more, but the roof plan indicates a somewhat expansive home. I would imagine that the architect and home owner would want the vault to remain intact to respect the design intent of the structure.
There are flitch beam design guidelines that are easy to find on the net.
RE: roof ridge beam support
That should render the hip members as simply supported members with cantilever ends supporting a simply supported ridge - no moment connections necessary at the LVL ridge. This could mean extra framing to pick up the point loads at the floor level though.
Mike McCann
MMC Engineering
http://mmcengineering.tripod.com
RE: roof ridge beam support
RE: roof ridge beam support
RE: roof ridge beam support
BA
RE: roof ridge beam support
I'd talk to the Arch and see if you can make a portion of the ceiling flat.
RE: roof ridge beam support
RE: roof ridge beam support
RE: roof ridge beam support
Garpe, I'm not sure about "overlap the lower flitch beam with the one at the high ridge..." Can you explain more, or sketch it?
RE: roof ridge beam support
There is no thrust at the bottom of the hips if you do moment welds at your ridge beam/hip beams. And if there was you have no way to resist it (vertial 10' wall x 5 1/2" thick with a horizontal point load at the top). Size your structure stiff enough to resist lateral deflections otherwise your finishes will develop a nice big crack right at your valleys.
You will most likely have to field weld or create a moment splice joint because the shape looks a little akward to be shipping down a 10' road. Coordinate with the contractor regarding his ability to fly steel through the air (i.e. assembly methods)
And before you go to all the trouble of designing this, call your architect and tell him that his requirements are leading to more difficult structure i.e. more $ which might make him rethink the flat ceiling and collar ties. After you get approval, then proceed.
RE: roof ridge beam support
Mike McCann
MMC Engineering
http://mmcengineering.tripod.com
RE: roof ridge beam support
RE: roof ridge beam support
The dormer on the left shows single dashed lines and there is a single dashed line where the stair is.
I would call the architect and ask to confirm.
RE: roof ridge beam support
A 9' cantilever in wood with an equal backspan on a residential house.....I wouldn't feel comfortable doing that. Let us know what you ended up doing.
RE: roof ridge beam support
Mike McCann
MMC Engineering
http://mmcengineering.tripod.com
RE: roof ridge beam support
A nine foot cantilever is equivalent to an eighteen foot simple span. And there are two of them to carry the reaction of the ridge beam. I believe that cantilevering the hip beams may be the most economical solution to the problem.
There may be other equally good solutions but the introduction of structural steel is not likely to be a winner.
BA
RE: roof ridge beam support
Garth Dreger PE - AZ Phoenix area
As EOR's we should take the responsibility to design our structures to support the components we allow in our design per that industry standards.
RE: roof ridge beam support
RE: roof ridge beam support
EIT