Posted: 8/25/2014 5:42:43 PM EDT
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I'm going to be building my own shed this weekend. The flooring, studding out the walls, and joining them, etc...no problem. And I'm also ok with papering/shingling.
However, creating the structure of the roof scares the hell out of me!! The math, angles , notching (bird's mouth), trusses is something I've never done and, if possible, I'd like to avoid having to do this weekend. Now a guy at Lowes showed me hurricane straps. He said that, using those, I wouldn't have to do anything to the boards. Just put them in place and screw them in (with however much overhang I want). But that doesn't make sense when looking at the peak. If I leave the edges without an angle there will be several inches of gap between the edge of each board and the ridge board...or do you just slide the OSB/plywood over it to meet and let that empty space along while nailing the sheet in wherever the boards actually end? I thought about doing a lean-to roof but then I'd have to worry about the side-walls being angled. No thanks. So two questions... Is there a super simple way to install a gable roof (again we're talking a shed here)....without much skill in regard to angles/measurements? Are there any diagrams or videos online showing such a simple technique? Thanks!! -Emt1581 |
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Go to sears and see if their framing squares still come with the instruction book. It explains everything. It isn't hard. Don't try to use hurricane straps to hold the rafter, they are for tying it down against wind, not snow load etc. Simpson does make a hanger that can be used and it attaches to both sides of rafter. Also, no screws! N10 nails. They are made for hangers and are engineered to take the loads. Try googleing how to cut a rafter. Don't be afraid to spend $5 on a trial rafter. http://www.thisiscarpentry.com/2012/11/09/common-rafter-framing/ |
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Never take everything the "guy at Lowes" tells you as an absolute fact.
I'll start with "Common" slope and using a speed square: Forget using degrees to measure for your slope... "Common" measures are much easier to work with in this context. An example of a common measure would be "3:12"; that is a measurement of rise over run, or rise:run. A 3:12 pitch means that for every 3" of rise(vertical), there are 12" of run. More simply put, the roof rises by 3" for every (horizontally-measured) foot of travel toward the center of the roof. You need to pick up a Speed Square to make these cuts- I think that Swanson-brand Speed Squares still come with an instruction manual. Usmcmp said to use a Framing Square, but that is not the best tool for this job. A Speed Square is a mostly-solid triangle with a lip on one of the short sides and a couple of hollow slots in the middle. One of these slots will be labeled "Common" and will have measurements from 1 to 18 on it- this is the part you will use for marking the slope angles. The first step is going to be determine your slope. If your ridge is 3ft above the header and the (horizontal) distance between the ridge and the outside header is 12ft, then you have a 3:12 Common slope. If the ridge was 2ft high and the (horizontal) distance to the header was 6ft then you'd have a 4:12 Common slope and so on... Once you know what the slope is, you can mark the boards. To mark slope on a board, first you should orient the board so that the "crown" will be on the top, or long end, of the board. Then place the speed square against the flat side of the board with the "lip" against the edge of the board and the pivot point toward the end. Carefully pivot the square up until the "3 Common" mark is aligned with the edge of the board (I'm using 3 as an example, use whatever number you determine the "rise" to be). Once you have the square aligned, hold tension on the square to keep it in place and mark a line on the board starting from the pivot point and going to the bottom of the square. This should leave a line which will give you the proper angle to cut. Stop and think about whether the line looks right before you cut; you may draw a couple of the lines on backwards before you get the hang of it. Also, be sure to leave yourself as much "extra" length on the board as possible when you make your marks, to allow for error. When your boards are cut you can hang them on the ridge board. I'm assuming that you already have a basic knowledge of how to mark the layout (set-back, OC, set-ahead, etc..) A framing nail gun is best for hanging them, but you can also toe-nail them at the top if you only have a hammer. You should secure them the rest of the way by driving 3 nails per side at a 45 degree angle (assuming 2x6 lumber), then you can add the clips with #10 nails. You really don't need to bother with the "birds mouth" notches at the header since you are clipping them as well. Just put the rafter tails on their marks, toe-nail them once on each side, and then install the clips. The clips at the header will normally go on the inside of the header and the left side of the rafter. While the roof will stand on it's own like this, it's a good idea to include horizontal supports that span from header to header as this will make the structure a lot more stable. If you do use horizontal supports, do it before installing the joists and it'll make your life easier-just be mindful of how it affects your layout at top and bottom. To cut all the overhanging rafter-tails off even to allow for facia installation, start by measuring down from the ridge to your chosen length on each end of the roof and mark the points, then pop a chalk line across all the rafters from point to point. Use this line as the pivot point to again mark your Common slope on each board (make sure it appears vertical). Cut them at the marks with a circular saw. Your rafters are now ready to accept a facia board. It's best installed with two people and may require a bit of "coaxing" to get it aligned just right. It's very important that you make sure the facia goes on in line with the roofs slope so that the plywood will lay flat across it. You can use the flat side of your square to make sure the OUTSIDE EDGE of the facia is in line with the rafters. Do not just mount it flush or else it will cause your sheathing to "bridge" up on the edge. Remember that hurricane clips are not a replacement for proper fastening- they are more of a supplement to keep everything rigid and not much else. I'm writing this at 0230 so I apologize if I carry on or if anything sounds like the delirious banter of a tired, dirty roofer- which it is. PM me if you need any advice. |