Measure the area for your shed. Slope-roofed sheds are most commonly placed up against fences or houses or in areas of heavy rain or snow.
Measure the the height for your shed, bearing in mind both the highest and lowest points of the sloped roof. Your shed should be tall enough to enable people person to access tools and equipment.
Draw a basic blueprint for your shed using your initial measurements. Be exact--precise measurements ensure a sturdy structure.
Purchase some lumber from a home improvement store or lumber mill. Use pieces of two-by-four or two-by-six lumber for sturdiness. If you are short on power tools but confident of your measurements, you can have the boards cut to size.
Purchase or borrow some basic tools needed to build the shed. You will need a hammer, spiral construction nails, a level, measuring tape, handsaw or circular saw, saw horses (for cutting wood), a shovel, a rake and a ladder.
Consider other equipment specific to your desired final product. You may want shingles for your roof, cinder blocks or bricks for a foundation, prefabricated windows or manufactured doors to finish your shed.
Cleaning the site, making sure the ground is flat and clear of rocks, debris and grass. Use a rake to even the area out and a tamping iron to level the ground.
Create a foundation with treated wood skids or cinder blocks. You can construct on top of buried cinder blocks or ones above ground, or you can skip the blocks and use water and pressure-treated wood to make a solid foundation.
Steak the four corners by digging four level holes, six inches deep. Stick four square, four-by-four or six-by-six pieces of lumber vertically into the holes. These will serve as markers for your floor. You can also use cinder blocks for this inside frame, as long as they are square and level.
Fill in the space around the wooden steaks with rock or pebble filler, making sure that they are secure and vertically level. For blocks, tamp them gently down into the ground, and spread some filler around the edges.
Create a floor frame around the four steaks or blocks with four pressure-treated two-by-four pieces of lumber. Cut the lumber to overlap at the corners (two sides being four inches longer and two sides being four inches shorter for two-by-fours). Nail these corners together.
Nail this floor frame to the four steaks or blocks. You should now have a more or less stable frame.
Make floor studs by vertically nailing pressure-treated two-by-fours at 16-inch intervals within this frame. You should now have a structure that resembles an unfinished chess board, with only the horizontal lines filled in.
Place three-quarter-inch plywood flooring on top of this frame, nailing the boards flatly into place to create a solid floor. You could also use three-quarter-inch wood planks to make slats for your floor, nailing each one into place at the frame's edges.
Use lumber to create wall frames similar to your initial floor frame. Make sure you have an adequate amount of studs (vertical boards) and leave room for windows if you are adding any. Most importantly, leave adequate space on the front wall for a door.
Raise the wall frames, nailing them each flat to the floor boards, then use additional lumber in the corners to nail them together. Cover these frames with plywood on the outside.
Raise the front of your shed by adding an extra level of frame to your front wall. You can do this initially by leaving that wall an extra eight to 16 inches taller than the others or by building an extra level afterward.
Measure the diagonal distance between the front wall of the shed and the back wall. This will indicate where on your diagonal roofing planks that you will cut your "birds mouths" or angled notches, to fit them to the tops of the wall frames.
Cut your notches into the diagonal planks so that they rest comfortably on the front and back walls at an even slope, with a little bit running off of each edge. Use roughly the same number of planks for the roof as you did for the floor. Use extra-long nails or screws to hold them in place.
Cover your roofing planks with plywood, leaving a slight overhang on all sides. Cut additional plywood to match the angles of your roof's slope. Nail these in the spaces created between the front and back walls.
Cover your new roof with shingles or tar paper to give it a water-resistant finish.