will a flitch plate work for a 4/12 pitch hipped cathedral ceiling? do i need to get it engineered before submitting to building dept. for a permit ?what thickness of rigid insulation above and is it really a cheaper and faster alternitive to scissor trusses and traditional insulating? what about sip’s?i’m talking about sandwiching 3/8 steel (with punched holes for bolts) between 4 common rafters to carry the hips in a exposed framing ceiling, a full penetration weld prior to the sandwich.and whatever simpson hardare available for hipto common connection and rafter to plate connections………………………………Thanks guys
Edited 7/4/2006 6:12 pm ET by djax
Replies
Are you talking about using a structural ridge beam for the roof? Yes, definaterly pay an engineer to calculate all the loads, and the beamm size, and the beam supports, and the rafter size.
"When asked if you can do something, tell'em "Why certainly I can", then get busy and find a way to do it." T. Roosevelt
no beam
flitch for what? The ridge, the hip, or the rafters?
is just the cieing hipped for a tray effect inside or are you talking about the roof?
What kind of house and roof style.
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I wonder if he's talking about steel plates installed as collar ties to avoid having a ridge...
Well, I've had another cup of Java and read it again, and there are lots of questions all half asked in there, so I'm really confused about what his design and intentions are.
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my guess, is that it all can be done with LVL's. Just have an engineer spec it all out before you go to the building inspector.
What "it" are you refering to though. Framing the hips and ridge?
Framing the whole shebang?
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Concrete will fix it.SamT
so would a Mister T treatment of Napalm!
;)
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only the commons where the hips connect
So you are talking about some kind of a joint connector instead of a flitch plate, I guess. Whether that is for the roof rafters or the cieling joists of the cathedral is still a big mystery. You are gonna have to learn to use a few more words to get your ideas and questions across before you find much for answers. What has been written so far can only be based on assumptions.
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my addition is 24feet wide, 32 feet long.my common rafter span is 12 feet.at the point where the commons meet the hips i propose to place 4 common rafters, 2 on each side of 2 pieces of 3/8 steel that have been welded at the plumb cuts.the steel is punched with 11/16 holes prior to assembly and 5/8 carraige bolts hold the whole thing together. a simpson hip connector plate attatched at the peak.
If you want to do something like that, why are you on the internet asking a bunch of non-engineer strangers? Get a properly engineered design and build it.
Michael Chandler recently wrote an article for FHB that I'm thinking describes what you're talking about...unfortunately, the magazine index works as well as the search funtion<G> I need a dump truck, baby, to unload my head
will a flitch plate work for a 4/12 pitch hipped cathedral ceiling? do i need to get it engineered before submitting to building dept. for a permit ?what thickness of rigid insulation above and is it really a cheaper and faster alternitive to scissor trusses and traditional insulating? what about sip's?i'm talking about sandwiching 3/8 steel (with punched holes for bolts) between 4 common rafters to carry the hips in a exposed framing ceiling, a full penetration weld prior to the sandwich.and whatever simpson hardare available for hipto common connection and rafter to plate connections
Are you talking about using a structural ridge beam for the roof? No beam.
my addition is 24feet wide, 32 feet long.my common rafter span is 12 feet.at the point where the commons meet the hips i propose to place 4 common rafters, 2 on each side of 2 pieces of 3/8 steel that have been welded at the plumb cuts.the steel is punched with 11/16 holes prior to assembly and 5/8 carraige bolts hold the whole thing together. a simpson hip connector plate attatched at the peak.
Appearant assumptions in the above:
There is an inheirent error in the way Hip Roofs are normally framed.
The Commons at the Hip to Ridge junctions carry the load of the Hips.
Somehow, Collar Ties are not needed even without a structural Ridge Beam.
It is not neccessary to have a tight fit between the Roof Sheathing and the Rafters.
The ends of the non structural Ridge Board need 4 Commons reinforced with 3/8" steel on each side to carry a 12' span. Or: There will not be a ridge piece at all and these 4 Flitch Beam Common Rafters will make up for it.
The OP is a qualified structural designer.
SamT
My brain is getting tied up in knots trying to visuallize this. Some other time I would draw what I think he is saying for feedback, but tonight will be a busy night for me
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I always like scissors trusses in a case like yours because they are strong and fairly easy to put up, and there is room for insulation and ventilation. Flitch plates are not always the answer; I think I read an article in FHB about them and that they allow sideways flexing of the beam unless the beam is restrained somehow. But as a couple posters said, if you have any doubts, get an engineer to design it (the roof system, not just the flitch plate).
well ...
that certainly clears everything up!
Jeff
Buck Construction
Artistry In Carpentry
Pittsburgh Pa
If you dont like scissor trusses your truss mfg. can make parallel chord trusses. These will have an engineers stamp on em. Some years ago my neighbor made some rafter /truss thingies using 2x12 and plywood. There is no beam ,just plywood flitch plates at the ridge. There are no other ties to prevent wall spreading. You cant do this in most locals these days but at the time the inspector said they would be fine.