I want to build my own trusses....please help?


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Old 05-03-05, 09:10 PM
Mnuvsteel
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I want to build my own trusses....please help?

Hi can anybody help me build my own trusses? I have been looking around on the net for info about how I can figure out what length I need to cut my rafters. and with all of the info there is , everyone seems to want to tell me how to erect pre fabed trusses. Well rich folks can worry about that ....I'm poor so I need to know how to build my own trusses. This is just going to cover a simple 10ft. x 12ft. shed. And the truss would span the 10 ft. width with 3 inches of rise in a 12 inch run and I suppose it wouldnt hurt to state that it doesn't snow here in the winter and the only load it would have is wind and its own weight.
 
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Old 05-03-05, 09:58 PM
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Small trusses like that are quite inexpensive- Maybe $30 or $40 a piece, which is less than you would spend in time and materials to make them. If that's too rich for your blood, you could always stick build it? No truss, just rafters and a ridge board, just like in the olden days.
 

Last edited by XSleeper; 05-03-05 at 10:18 PM.
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Old 05-04-05, 10:25 AM
Mnuvsteel
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yup that what I want to do...

Yeah that is what I want to do ...ridge board and rafter-- just like the old days...only troble is I ain't that good with a square hell I can barely spell it. Could you explain how I can figure out my rafter length and how I use a framing square to find the correct angle for the cut that sits on top of the wall?
Well I messed around last night a bit and accidentally got the correct cut for where the rafter sits on the wall plate , but I came up short on the ridge end. You may be thinking "wow this guy is a tard" about now. But I'm really not ....just a guy who had too much fun over the years that can't afford messing up any more lumber doing the trial and error method.
 
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Old 05-04-05, 07:04 PM
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In order to tell you an exact rafter length, I would need to know EXACTLY how wide your building is, from outside wall to outside wall at the top plate. I would also need to know how wide your soffit will be. (to determine how much longer the rafters need to extend beyond the exterior walls).

I also need to know whether you are using 2x4's for rafters? And if the exterior walls are also 2x4's? What will you be using for the ridge board? A 1x6 or a 2x6?

If your roof is a 3:12 pitch, just line up the inside edge of your framing square at 3" on the short leg of the square and 12" on the long leg to get the proper angle where the rafter meets the ridge. The long leg represents level, while the short leg represents plumb. Mark a line on the OUTSIDE edge of the short leg, and that's your angle.

The location of the bird's mouth is figured the same way, but you will be marking a line on the "level leg" of the framing square. And in order to know the exact point to make those marks, I would need you to provide that additional information I mentioned at the outset.
 
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Old 06-03-05, 08:11 AM
T-Square
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Originally Posted by Mnuvsteel
Hi can anybody help me build my own trusses? I have been looking around on the net for info about how I can figure out what length I need to cut my rafters. and with all of the info there is , everyone seems to want to tell me how to erect pre fabed trusses. Well rich folks can worry about that ....I'm poor so I need to know how to build my own trusses. This is just going to cover a simple 10ft. x 12ft. shed. And the truss would span the 10 ft. width with 3 inches of rise in a 12 inch run and I suppose it wouldnt hurt to state that it doesn't snow here in the winter and the only load it would have is wind and its own weight.



For your project, the easiest way is to lay it out in full scale on the back of a sheet of 4 x 8 plywood sheathing you are going to use to cover the shed.

With a chalkline snap a line 1 1/2" up from the long edge, use a small block of 2x4 draw its outline in the right or left corner below the line just made. This would be the top plate of the shed wall.

Measure off from the outside top edge, to the center of the span of 10'-00" which is 5'-00" using a framing square and straight 2x, draw a line up, to find the top of the ridge board centered on the line. Adjust up or down, to what looks good to you and for rain to run off the finished roof. That way you form your own roof pitch, to suit what you think is right.

After the 2x4 or 2x6 ridge is drawn, take a piece of 1x or place a nail 1" up from the top of the top plate outline, now lay one of your roof rafters, along the nail, and the other end up past the ridge outline, so its also 1" higher along the side of the ridge, using the square flat on the rafter, sight along the side of the ridge board outline, and mark the plumb-cut of the rafter, now cut this plumb cut, remove the nail above the top plate, and lay the rafter down so its top of the plumb cut is flush to the top of the ridge, and the bottom of the rafter is sitting on the top plate, lay out the plumb cut line along the top plate, 1" up from the bottom of the rafter, and draw the line of the top plate, producing the bird-cut, that will sit on the top plate. Make this cut, and lay the rafter down on the layout, you now need to find the overhang length, what ever looks good to you. This can be a square end or plumb cut, once this is cut on your rafter, you use this rafter as a template to mark and cut the others. Or if all the layout was done on cardboard, cut out the rafter template with a razor knife and use it to mark the other rafters.

Now you can either stick build your shed roof, or make trusses if you want.

To stick-build, nail two 2x4's flat on each end of the shed, extending up so the ridge board can be set at it's height and center line, with a piece of 1x nailed to the 2x4's to hold the ridge in place. Set each rafters bird-cut on the top plate, nail it to ridge and top plate, doing the four end rafters first, layout the centerlines of each truss or rafter or sidelines of same on both wall tops from the same end. nail in each rafter. You can use metal ties, or just sinker nails on each joint. If there is no roof overhang on the front and back of the shed just proceed to place roof sheathing on the rafters, with only one nail at each rafter end's plumb-cut, which has a 1x4 trim board to the ends of the rafters all ready nailed on. And from a ladder inside the shed mark the rafter centers on the 4x8 plywood or OSB board, square each rafter to the center marks and nail the sheathing down. Cut the sheathing the width you need to finish up to the ridge peak, on both roof sides, or cut back if you want a peak vent installed. In the event you want the roof to overhang on both the front and back, you need to add 2x4 braces, flat on 24" centers on and in the two end rafters/trusses, to support the 5/4 bargeboards/facia trim. The first brace being placed over the top plate or 24" from the end, with the end rafter being notched 1 5/8" deep and 3 1/2" wide @ 24" centers up the end rafters, measure back from the next rafter (un-notched) out to the length of the overhang you want, at both ends of the shed. The bargeboard ends being plumb cut, would be nailed to the plumb centerline on the end of the extended ridge board, and the other end nailed to the extended trim at the end of the rafters, and to each brace end. The roof sheathing being nailed to the trim and bargeboards around the perimeter of the roof, keeping it all square.

To build your own trusses, this can be done on the shed floor before the walls go up. Or on two sheets of plywood as a work table.

Layout the pre-cut rafters on the layout of top-wall plate, and plumb-cut side of the ridge board. 1x2 boards nailed down keep the rafters from moving, lay down a 2x4 to span the distance from bird-cut to bird-cut, scribe the cut angle of the bottom of the rafters on each end of this ceiling joist, now cut out 3/8" thick plywood triangle gussets. Cut two gussets to span both rafters, just under the ridge board bottom, nail to the rafter sides using roofing nails, construction adheasive can be used also. Apply gussets to one side, flip the truss over and glue and nail remaining gussets, repeat until all trusses are done. Depending on the span of the trusses, vertical braces can be added between the ceiling joist/ now a bottom cord of the truss, which would also require gussets on both sides. While this is not an engineered truss, using structral grade lumber and attachment plates, it can be used for small out buildings and pole barns (which in most cases use double bottom truss cords, and bolting through gussets) where spans are greater than 10'-00".

All the oldtimers built there own trusses, as do post and beam builders, log home builders, and now you!! Enjoy your new shed!
 
 

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