Barn/Shed Roof?

greenspun.com : LUSENET : Countryside : One Thread

Forgive me if this has been answered before but I couldn't find it anywhere. I'm a novice "do-it yourselfer" and I'm about to build a utility shed (10' x 12'). When I get to the roof, I'm not sure how to build the trusses. Cut all the angles at 45's then use metal plates to fasten together? Toenail to the top of the studded walls? 12" overhang standard?

Also, I'm using T-111 for the siding. Is it O.K. to run it to the ground? Using treated lumber for the floor frame then plywood...was going to run the siding to the ground(gravel). Should I use 4x4 runners under the floor....hope not..$$$.

Thanks in advance for any and all responses. Seems like a good bunch here. Mike

-- Mike (smfine@yahoo.com), August 06, 2001

Answers

For your root, What kind of roof you planning and where do you live? Snow load, wind loads all play into how your roof should be built. A 45deg angle is going to make for a mighty steep roof, is that needed? Again snow load will play into this. What does code say if thats an issue in your area? Many area dont allow you to make your own truesses, they must be enginerred.

T1-11 is not good to the ground. You need to keep water away from it. I will wick up water.

-- Gary (gws@redbird.net), August 06, 2001.


Mike, if your going to put a peaked roof on the shed do it this way. First of all rooves are sized by the number of inches that they rise (or fall)in a 12 inch distance, such as 3 in 12 (easy slope) up 30 in 12 (such as an alpine "A" frame), normally 4 to 6 in 12 for most regular sheds. Get a 2 foot framing square, lay your rafters on a saw horse, place the bowed edge away from yourself, place the 2 foot square with its outside cornor pointing towards yourself, lying flat on the rafter. The short leg of the square is placed (using the outside inch marks) at the inch in 12 that you decide to use, place the long leg (outside marks) at 12 inches, mark accros the rafter aganist the short leg, this is the part that is at the top of the roof.

Now install a "ridge pole" with temporary vertical supports, make sure it is absolutely vertical. A ridge pole is usually a 1 by 6 inch board on edge for 2 by 4 or 2 by 6 rafters. Measure with total accuracy the distance from the top outside edge of the ridge pole to the outside edge of the top of the side wall. This distance is then transfered to the rafter, marked at 1 1/2 inch above the where the rafter will contact the side walls upper plate. Take the angle from the top cut and transfer it to the mark and add another mark at 90 degrees to the first cut end, remove this little wedge shaped piece of wood. Test fit your rafter on both sides of the ridge pole and if your satisfied, then use it to cut the rest of the rafters.

If you go buy a new square there is an instruction booklet that comes with it that has pictures and is proabially better to exsplain this.

-- mitch hearn (moopups1@aol.com), August 06, 2001.


depending where you are,, the type of weather,, snow ect,, you could just make one side higher than the other,, and have a slanted roof. Also,, not a good idea to run T 111 to the ground,,the edges soak up water,,and willl rot,, give it at least 6 inches above ground, if not more. And stain it once a year.

-- STAN (sopal@net-port.com), August 06, 2001.

Mike,

I agree with Stan on both counts. Use something different for your siding material that won't wick up the water. Your local lumber/building material supply house should be able to help you there. As to the roof, I'd go with a shed roof, too. My only additional suggestion would be to angle it away from the door. In other words, make the door side the higher side. That way rain won't pour off the edge on you when you're trying to get in or out and snow won't slide off leaving a pile to move before you can get through. I hope this helps.

-- Gary in Indiana (gk6854@aol.com), August 06, 2001.


Mike: UBC (Uniform Building Code) requires any untreated wood in a building structure to be a minimum of 6" from the ground.

Unless you are in an area of heavy snow load a 4/12 pitch is the easiest to work with and sheds wind and rain well. You can stand on the roof surface to work without sliding off. If you have never done roof framing before you really need to go to a bookstore and get a how-to book on framing. There are too many tricks for us to be able to explain here without pictures and diagrams. I have looked for websites with this kind of information and have come up empty. You can also pick up a condensed copy of the UBC that covers typical residential frame construction that will provide charts that tell you how far you can span with what dimension lumber of various species of wood and for what purpose (i.e.: floor, cieling, roof). Your snow load, pitch, span, and wood grade and specie are all important in determining what size lumber to use.

Here are a few tips: You say your shed is 10x12. With a 4/12 pitch your rafters will be about 5- 1/2 feet from ridge to top of wall. Use a framing square with the roof pitch formulas on it to determine the exact legnth and how to cut the ends. You can get one at most hardware stores with basic instructions. For 5-1/2 foot span you should be able to use 2x4's unless you expect a heavy snow load. As was said above, run a ridge pole the legnth of the building. It is supported by the end walls and extends out the width of your eaves at each end. You can toe- nail or use joist hangers to attach the rafters to the ridge pole at a spacing of 16" on center. (The rafters at the end are set in so the 16" measures to the outside edge.) Cut the end of the rafter with the same angle as the top end. You need to figure for extra legnth for the eaves, if any. If you are using 3 tab shingle roof, then sheet the roof with 1/2" plywood or wafer board and then cover with building paper. Apply the shingles according to the instructions on the package.

Your wood floor needs to be off the ground by at least 6" inches. Set it on concrete pier blocks, or pour your own pier footings. I have done this for several small structures by digging two feet deep with the post hole digger and using scraps of 6" plastic drain pipe to form the piers above ground. Dig the hole just the diameter of the pipe at the top, but expand it at the bottom. Roll up a piece of old fence wire for reinforcing and fill the hole and pipe with concrete. After the concrete is in, insert an anchor bolt. Level the tops of the 6" pipes so they are all on the same level. Once set, run beams across the tops and secure in place with the anchor bolts. Build your floor on these. If you set your beams in about an inch from where the siding will be you can add a cedar or treated wood skirting around the base to keep the bigger critters out. Don't set even treated wood directly on the ground for a building - even an inexpensive shed - as it will rot in time and it will be almost impossible to get the floor level and keep it level.

-- Skip in Western WA (sundaycreek@gnrac.net), August 06, 2001.



Gary, no I guess 45 degrees isn't needed....live in Western PA some snow but not enough to worry.

Many thanks to all that have contributed especially Skip. I appreciate the long, thorough response and the time you spent replying. This helps a lot. Guess I'm off to Lowe's this weekend to get a square then take it from there.

-- Mike (smfine@yahoo.com), August 07, 2001.


Moderation questions? read the FAQ