How to Build an Outdoor Shed for a Composting Toilet

An outhouse style shed can be altered to fit a compost toilet.

Composting toilets are mainly used indoors, but before there was indoor plumbing there were outhouses. An outhouse was technically a composting toilet but not as efficient. You can combine the two, creating an environmentally safe and efficient outdoor shed for use away from home. Hunting cabins and camping areas are ideal locations for this type of use. You will need either a 12-volt battery or a solar cell to power the toilet once installed. The shed itself can be completed in a day with help.

Things You'll Need

• 4 boards, 2-by-4-by-48-inches
• 4 boards, 2-by-4-by-60-inches
• 2 boards, 2-by-4-by-72-inches
• 2-by-4-by-24-inch board
• 60-by-60-inch corrugated roofing sheet
• 4 posts, 4-by-4-by-60-inches
• 1-inch plywood sheet, 48-by-52-inches
• 3 plywood sheets, 1-inch thick, 4-by-7-feet
• 1-inch plywood sheet, 4-by-6-feet
• Measuring tape
• Hammer
• 3-inch nails
• Circular saw
• Drill and drill bit
• Wood screws
• Hinges
• Eye bolt
• Eye hook

Instructions

Floor and Roof Frame

1. Lay a 4-foot 2-by-4 board with the wide face vertical. Set a second 4-foot 2-by-4 board the same way with the end butting against the inside corner of the first board forming an “L.” Drill screws through the side of the first board into the end of the second board. Repeat this step at the open end of the second board and for each corner.

2. Flip the floor upside down. Set a 60-inch 4-by-4-inch post at each corner. Drill two screws through the frame into the posts, one screw per side of the post. Flip the floor upright to stand on the legs.

3. Construct a frame similar to the floor out of 60-inch 2-by-4-inch boards. This is the roof frame. Set a 60-by-60-inch corrugated metal sheet over this frame so there is a 6-inch allowance on all sides. Drill screws through the metal into the frame to complete the roof.

The Door

1. Lay a 4-by-7-foot plywood sheet flat. Measure and mark a 6-foot high by 2-foot-wide area on the board. Cut out the measured area. Set the cutout aside. This is the door and doorway.

2. Set a 2-by-4-by-72-inch board on either side of the doorway with the wide edge facing the opening. Drill screws through the plywood into the boards. Set a 2-by-4-by-24-inch board between the boards at the top of the doorway. Drill screws through the long boards into the ends of the short board.

3. Measure and mark a point 2 feet up one of the sides of the door frame. Repeat the measurement from that point. Repeat the step on the face of the cutout using the same side. These are the hinge locations.

4. Install hinges on the door frame. Line up the door with the frame. Drill screws through the hinge holes into the door.

5. Screw an eye bolt into the frame opposite from the hinges midway up the board. Screw the latch into the door so it fits securely into the eye bolt to close the door.

The Walls

1. Lay two 4-by-7-plywood sheets flat. Measure down the right side from the top 12 inches and mark this point. Draw a line from the left upper corner of the sheets across to the point made from the measurement on the right. Cut the plywood along these lines. This creates the pitch of the roof.

2. Nail the wall with the door to one side of the frame with the 4-foot side flush with the side of the frame. Repeat the process on the opposite side of the frame with a 4-by-6-foot plywood sheet. These become the front and back of the shed.

3. Set one of the side sheets against the frame so the high side lines up with the front of the shed. Make the adjoining sides flush. Nail the sheet to the other sheets and frame. Repeat this step with the other side sheet.

4. Cap the shed with the roof. Drill screws through the interior sides of the shed walls into the roof frame on all sides.

Toilet Installation

1. Set the end of the tape measure at a back corner where two walls intersect the floor. Extend the measuring tape 18 inches along the base of the back wall and mark the point. Measure 12 inches from that point with the tape and mark another point. Extend the end of the tape from either point created toward the front of the shed 45 inches. Mark that point. Make the same measurement from the other point on the back wall. The area between the points is where the toilet will be placed.

2. Measure the distance from the toilet base to the vent pipe hole in the toilet. Measure the same height along the back shed wall within the pre-measured area for the toilet. Set the vent pipe end against the back wall with the mark at the bottom of the pipe. Trace an outline of the pipe on the wall. Remove the pipe.

3. Drill four holes around the hole outline equidistant from one another. Insert the jigsaw blade into one of the holes. Cut the outline to create the opening for the vent pipe.

References

• Woodworkers Workshop: Building Outhouse Construction Plans
• Mother Earth News: Mother's Compost Commode