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-   -   Need Help with a pitch roof (http://www.diychatroom.com/f9/need-help-pitch-roof-91552/)

hotdog2 01-06-2011 08:03 PM

Need Help with a pitch roof
 
I built a 10x14 building and am wanting to put a pitched roof. My question: Is there an easy way to figure the angles? I'm about to run out of wood with this trial and error method! Lol

I have 2x6s around the edge of the building and want to go up about 32" high for the peak. My problem is finding the angles for each side where it lays on top of the 2x6 and the angles where it will butt up on the peak.

Thanks in advance for any help.

KarlJay 01-07-2011 04:01 AM

One simple way that I used was to prop it in place where you want it using clamps... Then take a straight edge and mark the lines, this will give you the angle then I cut it too long and trim to find where the cut should be. Use that as a template for the others after you confirm it fits right.
I have a hip roof and it has a BUNCH of complex cuts and I used scrap wood to test fit, then keep it as the template.
If you're making trusses, you can lay out a form or jig from old plywood then use the plywood for sheeting later... no loss

For the center cuts, I use a plumb-bob and draw a cut-line off of that.

RickyBobby 01-07-2011 07:35 AM

A rafter book that usually comes with the Johnson speed square is a great guide.

Like KarlJay stated, start by getting things in place and make your marks. Get your ridge centered and at the height you want and go from there. Your common cut (roof pitch) will be first and then you can make marks for your seat cut.

Once you get one figured out, test it on the other side, mark it as your pattern and mark the rest of them.

krauseconst 01-07-2011 12:25 PM

if the building is 10' wide just divide by 2 that is 5' so you want 32'' take 32 divided by 5 that is 6.4 or 6 3/8" for every foot you go over you go up 6 3/8''. So you got that taken care of now if you have 2x4 rafters it is going to come up 3 1/2'' that you have to compensate for. make a jig and just lay the next one on top. good luck with your project.

hotdog2 01-07-2011 08:00 PM

Quote:

Originally Posted by KarlJay (Post 564518)
One simple way that I used was to prop it in place where you want it using clamps... Then take a straight edge and mark the lines, this will give you the angle then I cut it too long and trim to find where the cut should be. Use that as a template for the others after you confirm it fits right.
I have a hip roof and it has a BUNCH of complex cuts and I used scrap wood to test fit, then keep it as the template.
If you're making trusses, you can lay out a form or jig from old plywood then use the plywood for sheeting later... no loss

For the center cuts, I use a plumb-bob and draw a cut-line off of that.

Thanks KarlJay, That's exactly what I did and it works!:)

hotdog2 01-07-2011 08:56 PM

Quote:

Originally Posted by krauseconst (Post 564704)
if the building is 10' wide just divide by 2 that is 5' so you want 32'' take 32 divided by 5 that is 6.4 or 6 3/8" for every foot you go over you go up 6 3/8''. So you got that taken care of now if you have 2x4 rafters it is going to come up 3 1/2'' that you have to compensate for. make a jig and just lay the next one on top. good luck with your project.

Thanks Krauseconst, I am using all 2x6s. I did today what KarlJay suggested and am finding the right angle on the peak where I butt them up, but finding the other angle on the end that suppose to lay on the 2x6 is giving me a fit!:thumbsup:

chrisBC 01-07-2011 11:30 PM

yeah either put in place and use plumb lines, as mentioned,

or to calculate, (for a common) figure out your total run, (half of measurement from wall to wall of building, for the run of your rafter) use your roof slope to figure out your total rise, the hypotenuse of this is the line length of your rafter. Or, if you know how high you want the peak to be, calculate your total rise with your known total run, (asquared plus bsquared equals Csquared, 3,4,5) csquared will be your line length. Or just use your rise/run to know how to cut your angles (plumb cuts, seat cuts if necessary) birds mouth if necessary

you can use this rise/run to mark your speed/framing square to cut the angles, figure out the line length, might be easier than sitting up on a roof trying to make marks on a rafter.

Once you know it works, use as a template for the rest of your commons..

KarlJay 01-09-2011 04:40 AM

Quote:

Originally Posted by hotdog2 (Post 565170)
Thanks Krauseconst, I am using all 2x6s. I did today what KarlJay suggested and am finding the right angle on the peak where I butt them up, but finding the other angle on the end that suppose to lay on the 2x6 is giving me a fit!:thumbsup:

I assume you're talking about the "bird's beak"... Set one in place without the cut, place a straight 2x4 or straight edge and lay that on the 2x6 topper, pencil across the top of the straight edge and that's the angle you need for one cut. the other cut is 90 deg off that and it would be at the far edge of the 2x6 topper.

You could just get a scrap piece and match the angle by placing it next to the the real one (like a double thick rafter) then guess the cut and keep trying the cut till it fits perfect, that scrap becomes your pattern for the rest. I made several patterns from scrap and maked them.
Like I said before, I had a bunch of complex cuts and making a few patterns out of scrap saved me a lot of waste.

hotdog2 01-10-2011 07:06 PM

I really appreciate your help. The answer for the birds beak sounds so simple, I feel like kicking myself! Lol

Thanks again!!

Robert F 01-10-2011 08:31 PM

:thumbsup:


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