Reframe trussed space as conventional without tearing down structure?


I have space over a garage I'd like to convert to a 4th bedroom for an upcoming child. The space is trussed and I was thinking of sistering conventional framing beside all the trusses then cutting the obstrucing portions of the trusses out. I don't want to tear down the entire garage and throw away a perfectly good roof and siding and I don't want to disrupt the neighborhood with a month's worth of torn up house. The roof line is a simple A frame. I've built another addition on my house after which the building inspector said I did a very good job so I'm not a complete novice. The real question: is this idea crazy stupid or has it been done before?
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wrote:

Just remember that the truss does two things, it holds the roof deck up, and it keeps the walls that the roof rests on from coming apart. As long as you replace BOTH those functions (joists and rafters) you should be ok.
Is the garage door in the gable end, or one of the load bearing walls? 'Cause if your new rafters rest on the wall with the door in it, you'd best make sure that whatever beam goes across there is sized to take half the floor.
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smcjensen wrote:

(Scratching head) It sounds weird at first but I can see it working with some problems.
Fastening the joists and rafters to the sill plates would be a problem due to nailing room. I wouldn't trust just sistering to the bottom/top chords of the trusses but it might work.
Your framing lumber would have to be much larger than the truss sizes.
Harry K
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smcjensen wrote:

Trusses are funny things. I strongly suggest you get a real structural engineer to take a look at the situation and make a recommendation. You are going to need to resize the structural units and make sure they are large enough. With trusses it is not easy to judge since they are complex units that relay on each other for strength.
--
Joseph Meehan

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Joseph Meehan wrote:

skeptical that it would work without a structural ridge beam, which would add a layer of complexity to your plan. Could be done, but it wouldn't be a cake walk.
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This sounds like the perfect place to use the ole "Opportunity cost" in other words, what will you give up, to gain something else.
Due to the structural uncertainty you may cause, the question of code as to whether a bedroom above a garage is plausible, and the time it will take to fiddle with what you have it may be WAY better to remove the roof and get what you really need. I suspect the reduction in headaches and I am sure it will take far less time to take down the roof and do it.
However, I'd check code first about a bedroom over a garage.
Very Respectfully, Fred
smcjensen wrote:

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