MAMEWorld Forums - The Loony Bin - More garage talk, rafter edition part 1.

> Finally finished enough of the little things on the ground to start thinking about a
> roof. For those following along with their own adventure in mind, the type of roof
> you are putting up should have been decided already. It's not too late to change
> things if you must. I priced both prefab truss and "stick frame" (cut everythig
> yourself). I'll elaborate on the pluses and minuses a bit in this post.
>
> Prefab truss:
> Easy as pie to install, lightweight, and fairly sturdy. You can get them with an
> actual "room" preformed in them as well. They typically call these attic trusses.
> They are considerably more expensive too. They aren't going to hold as much weight as
> a majority of stick framed roofs. I'd say prefab is the way to go for low sloped
> roofs, or if you are dead set on quick and easy. For my garage, attic trusses at the
> pitch I wanted (10/12) would cost me $1400-$1600.
>
> What a prefab truss looks like
>
>
> Stick Framing:
> This route is not as easy as prefab. It takes a little more math, and a step up in
> carpentry skill. Those negatives aside it's sturdy as all heck, Leaves you with a
> nice open attic space, and just looks cooler. I chose this method for my garage as it
> was $500-$700 cheaper, for an attic that would hold 3x the weight.
>
> What stick framing looks like
>
>
> Now on to the big question, how the hell do I build it? The first thing to do is draw
> a mock up of what you have in your head. It can be as simple as a triangle on a piece
> of paper with some basic measurements. For a square building, you are pretty much
> going to build this triangle over, and over, and over, and over....
>
>
> Once you have your triangle, look up your local codes for how much weight this thing
> needs to hold. This will be your bare minimum spec, build up from here if you want. I
> found a ton of nice calculators online that figure things like dead and live load,
> span charts, snow load charts, pitch charts, and just about every other chart you
> could imagine. Your head is going to spin, and probably hurt. After a few days of
> reading you should have a decent understanding of what you need to do and how to tie
> all the numbers together. You could also farm this part out to a carpenter buddy, or
> an engineer of you are dealing with something tricky.
>
> For my garage I decided on 2'x12'-18' rafter ties. This is quite a bit of overkill
> for a rafter tie, yes. The bonus in using such thick wood is two fold.
>
> 1. 2x12's made the 18' span fine for the weight I wanted to support.
> 2. Thick rafter ties double as excellent floor/ceiling joists.
>
> I chose 2x8's for the actual rafters as that seemed a pretty common size to use. It
> also met the load requirements for my village (and then some) for the span it needed
> to make.
>
>
> So I have my roof planned and again the question comes up, "How the hell do I build
> it?" If you aren't familiar with cutting rafters, read. Read a ton. Plan on wasting a
> board or two practicing as well. It's not hard to do, but it is repetitive. You'll
> need a good framing square, a pencil, and a saw.
>
> Now before you begin cutting, a little note. The more perfect your cuts are, the
> stronger your roof will be. On that note, it realllyyyy sucks to have pre-cut all
> your rafters and find out they are wrong when you try to place them. It also really
> sucks to have to cut each rafter on the fly, and makes for a long day (an even longer
> day if the temperature outside is 20F). How do you do both then? Great question. One
> I asked to a few people. The best answer I got back was "Build a jig."
>
> My fist thought on the matter was "A jig! Why didn't I think of that!"
>
> My second thought was "WTF is a jig?".
>
> To be honest I'm still not entirely solid on the definition of "Jig" myself. It seems
> to me that carpenters use it to describe anything they don't have a proper name for.
> Loosely ~I'd~ describe it as anything that helps you make something else. So a jig
> building I will go....
>
> My jig was more for "quality checking" than cutting as shown below. It did help me
> see that my plumb cuts were off a tiny bit, which was well worth the 20 minutes and
> scrap wood it took to build it.
>
> A quick tidbit of advice on making "templates" for your rafters. This is fine to do
> and will save you a lot of time. The only important thing to note is that you should
> use the SAME template for every rafter. This prevents "wandering" of your marks. If
> you used the rafter you just cut to make your next rafter and so on, the last rafter
> you cut will be nowhere close to the first. I guarantee it. It's the carpentry
> version of that telephone game you played in school.
>
>
> To be continued...

you should compile all of this on a webpage. very good reference