When it comes to building a shed roof you need to keep in mind that it could be subjected to extreme loads if you live in an area that gets any measurable amount of snowfall. You want to build a sound structure that protects the contents of your shed and will last for years to come.
When you buy your set of shed plans, make sure you note the roof construction and that it conforms to local building codes. Once you are sure that is does you can go to the local lumber yard and they will fabricate the necessary roof trusses for you.
Once your roof trusses are delivered just mark with a pencil the top plate of the wall every 24” on center. Place the roof truss on the first mark and nail it into place. Repeat this process for the remaining trusses.
Most roof designs will call for 5/8” decking to tie the trusses together and to support the roof loads. Install the decking and then cover with asphalt roofing paper and shingles.
One very important thing to remember is to not deck the roof on a windy day as the large surface of the boards can catch the wind and take you off the roof quite easily. Always get help handling the large roof trusses as well as the decking material.
If you live in an area with heavy snow fall it is a good idea to make your roof pitch as steep as possible so the snow will slide off and not accumulate. Snow accumulation can reach thousands of pounds and put even the most sturdy of structures under tremendous stress loads.
It is a good idea as well to go with at least a 20 year shingle and to buy a color that matches the shingles on your home’s roof. Not only is this more pleasing to the eye it may be a requirement if you live in a community with a home owner’s association… I learned this the hard way!