This step by step diy woodworking project is about 12×20 shed plans. The project features instructions for building a large shed with one large window and one access door. If you want to create backyard storage space or even a small studio, building this large shed is a great idea. Make sure you take a look over the rest of plans to see alternatives and more projects for your garden.
When buying the lumber, you should select the planks with great care, making sure they are straight and without any visible flaws (cracks, knots, twists, decay). Investing in cedar or other weather resistant lumber is a good idea, as it will pay off on the long run. Use a spirit level to plumb and align the components, before inserting the galvanized screws, otherwise the project won’t have a symmetrical look. If you have all the materials and tools required for the project, you could get the job done in about a day.
Projects made from these plans
12×20 Shed Plans
- A – 5 pieces of 4×4 lumber – 240″ long SKIDS
- B – 16 pieces of 2×6 lumber – 141″ long, 2 pieces – 240″ long JOISTS
- C – 5 pieces of 3/4″ plywood – 48″x96 long, 5 pieces – 48″x48″ long FLOOR
- D – 13 pieces of 2×4 lumber – 90″ long, 1 piece – 240″ long, 1 piece – 233″ long, 2 pieces – 97 1/2″ long, 2 pieces – 48″ long, 4 pieces – 39″ long, 4 pieces – 10″ long, 2 pieces – 76 1/2″ long, 5 pieces – 9 1/2″ long, 2 pieces – 36″ long, 5 pieces – 37 1/2″ long FRONT WALL
- D – 13 pieces of 2×4 lumber – 90″ long, 2 pieces – 240″ long, 1 piece 233 ” long BACK WALL
- E – 2 pieces of 2×4 lumber – 137″ long, 1 piece – 140″ long, 7 pieces – 90″ long 2xSIDE WALL
- F – 16 pieces of T1-11 siding – 48″x94 1/2″ long SIDING
- G – 2 pieces of 1×4 lumber – 78″ long, 1 piece – 55″ long, 2 pieces – 45″ long, 2 pieces – 71″ long, 1 piece – 38″ long DOOR
- 5 pieces of 4×4 lumber – 20′
- 2 pieces of 2×6 lumber – 20′
- 16 pieces of 2×6 lumber – 12′
- 6 pieces of 2×4 lumber – 20′
- 6 pieces of 2×4 lumber – 12′
- 50 pieces of 2×4 lumber – 8′
- 6 pieces of 1×4 lumber – 8′
- 16 pieces of T1-11 – 4’x8′
- 8 pieces of 3/4″ plywood – 4’x8′
- 1000 pieces of 1 5/8″ screws
- 1000 pieces of 2 1/2″ screws
- 16d nails
It’s that simple to build a 12×20 shed – Video!
How to build a large 12×20 shed
The first step of the project if to assemble the floor frame. Cut the components from 2×6 lumber at the right size. Drill pilot holes through the rim joists and insert 2 1/2″ screws into the regular joists. Place the joists equally-spaced, as shown in the plans. Make sure the edges are flush and check if the corners are right-angled.
Fit 4×4 skids under the floor frame, in order to protect the components from moisture. Drill pilot holes through the skids and insert 3 1/2″ screws into the frame.
Attach the 3/4″ plywood sheets to the floor frame, making sure you follow the patterns described in the diagram. Leave no gaps between the sheets and secure them to the joists using 1 5/8″ screws, every 8″. Use tongue and groove plywood sheets, for a professional result.
Build the front wall from 2×4 lumber. Cut the components at the right dimensions, making sure you follow the information from the plans. Drill pilot holes through the plates and insert 2 1/2″ screws into the studs or 16d nails.
Make sure the corners are right-angled and check if the edges are flush. As you can easily notice, you need to frame the door opening and the window opening. You can adjust the dimensions for the walls to suit your needs. Notice the double headers for the door and window.
Building the back wall is an easier job, as it doesn’t require intricate measurements and cuts. Drill pilot holes through the top and bottom plates and insert 2 1/2″ screws into the studs. Place the studs equally-spaced and make sure the corners are right-angled.
Fit the front and the back walls to the floor and use temporary braces to lock them into place. Plumb the walls with a spirit level and align the edges with attention. Drill pilot holes through the bottom plates and insert 2 1/2″ screws into the floor of the shed.
Build the side walls from 2×4 lumber. Drill pilot holes through the plates and insert 2 1/2″ screws into the studs. Place the studs equally spaced, but make sure you align the edges. The top plate should overhang 3 1/2″ on both sides of the wall.
Fit the side walls to the floor of the shed, as shown in the diagram. Drill pilot holes through the bottom plates and insert 2 1/2″ screws into the floor. In addition, lock the adjacent walls together by inserting 2 1/2″ screws through the studs. Make sure the corners are square and check if the edges are flush one with another.
Fit the T1-11 sheets to the front wall frame, as shown in the plans. Align everything with attention and lock them into place with 1 5/8″ screws or nails, every 8″ along the framing. Leave no gaps between the siding and the wall frame. In addition, make sure the top edge of the sheets is aligned with the top plates.
Fit the siding to the back wall, in the same manner described above.
Fit the siding to the side walls, making sure you align the sheets properly.
Fit the 1×4 trims around the door opening, as shown in the diagram. Use 2 1/2″ screws or nails to lock the trims to the framing.
The next step is to build the door for the 12×20 shed. Use the piece that you cut out in the previous step for the door panel. Attach 1×4 trims to the door panel, as shown in the diagram. Align the edges with attention and use 1 5/8″ nails to lock the trims into place.
Fit the door to the opening, as shown in the plans. Use hinges and a latch to secure the door into place. In addition, you could install a 1×2 door stop under the door header.
Last but not least, you should take care of the finishing touches, as to be able to continue the process with the rest of the steps. Fill the holes with wood putty and smooth the surface with fine-grit sandpaper.
Top Tip: Check out the rest of the project, if you want to learn more about building a roof for the 12×20 shed. Premium Plans available for this shed size, in the Shop.
This woodworking project was about 12×20 shed plans. If you want to see more outdoor plans, check out the rest of our step by step projects and follow the instructions to obtain a professional result.