Materials and Preparation
Purchase some 2-by-4 timbers and plywood sheeting along with some 1- and 2-inch screws or nails. If you are planning to build a floor, add extra 2-by-4 timbers and plywood sheeting to accommodate that. You also will need shingles, tar paper and roofing nails for the roof if your design calls for it. U-hook straps will make constructing a roof truss system easier if you are leery about making right angles. These straps help by taking the guesswork out of building roofing trusses by making it easy to connect supports and eliminate the need for cutting the perfect angle.
A back yard barn designed for housing animals is built from the poles up. Mark out the space you have allotted for the square footage of your barn, and then sink 4-by-4s into the ground every four feet around the perimeter, framing in any window spaces in your design plan. Run a header or top plate on top of the 4-by-4s and cover the poles with plywood siding. Install your double-pitched roof frame, allowing for any loft space you may want when planning your pitches. Cover your double-pitched roof frame with plywood sheeting or corrugated tin roofing. Build the frame for your loft, if desired, inside the barn and cover it with plywood sheeting. Use a sturdy frame and hinges when hanging the front doors to handle the weight.
A work shed layout and design starts with a boxed wood frame floor covered in plywood. Attach the frame walls to the floor with nails or screws, framing for any windows you've planned. Cover the outside with wood siding or plywood. Covering the inside wall is optional and should be done after installing wiring for electrical outlets and lights. An option for covering the inside walls is to use peg board for all or part of the wall to allow you to hang tools or to build a permanent work bench. For the roof, frame a double pitch truss system and cover it with plywood.
The storage barn design incorporates the box frame flooring like the work shed and the loft of the animal barn. The walls are made the same as the work shed but may have fewer or no windows. Storage sheds also use the double pitched roof system. Determine your roof pitches by how much loft space you want.
The roof of your backyard barn will need to be shingled and the siding weather proofed to keep water out of your shed. Seal the walls with exterior paint or by covering with siding, if desired. Decorative touches can be added to give your barn a certain look using decorative trim with scrolled designs already cut into it.