How to Build a Potting Shed

The directions specify using cedar timber framing with simple lap joints; however, they can be easily adapted for 2×4 construction. The walls are built with 1×8 shiplap cedar, but any siding, including board and batten, can be used. Similarly, any roofing material can be used.

If you don’t want to build your own windows, you can order single-sash barn windows from a lumberyard. Or, to save a bit of money, salvage windows from old houses to use in your shed — just make sure they’re all the same size.

Floor Framing

Clear a flat surface, and measure and mark the space on which your shed will be built. The floor frame will be supported by concrete blocks under each corner. This will allow you to move the shed, if necessary.

From the 12-foot 2x6s, cut six 10-foot-9-inch boards. (Two for the frame sides and four for the floor joists.) Assemble the floor frame with two 10-foot 2x6s for the front and rear, and two 10-foot-9-inch 2x6s for the sides. Nail the frame together so the rear and front pieces overlap the side pieces.

Settle the concrete blocks into place on the ground, and then position the floor frame on top of the blocks. Square the floor frame so the diagonals measure 14.86 feet (178-3/8 inches). Make sure the frame is level. Adjust the concrete blocks with shims if necessary. Install four floor joists at 2-foot intervals. Cut and toenail 2×6 “blocking” between floor joists. Nail down 2-1/2 sheets of plywood using 6d nails every 8 inches. Create the floor of the open deck by nailing the 10-foot decking boards across the floor frame.

Tools and Materials

Floor Framing

• 12-foot-long pressure-treated 2x6s (2), for frame sides
• 10-foot-long pressure-treated 2x6s (3), for blocking and front and rear of frame
• 12-foot-long pressure-treated 2x6s (4), for floor joists at 24 inches on center
• 4-by-8-foot sheets of 3/4-inch exterior-grade plywood (3), for flooring
• 10-foot-long pressure-treated 5/4×6 decking boards (6), for rear deck
• 4-by-8-by-16-inch concrete half blocks (6), for foundation
• 6d nails

Wall Framing

• 6-foot-long cedar 4x4s (6), for corner and door posts
• 5-foot-long cedar 4x4s (2), for rear corner posts
• 10-foot-long cedar 4x6s (3), for front, middle, and rear beams
• 8-foot-long cedar 4x6s (2), for side beams
• 10-foot-long cedar 4x4s (2), for knee braces
• 6-foot-long cedar 2x4s (10), for wall studs
• 8-foot-long cedar 2×4, for rough sills
• 6-inch spikes (12), for beam lap joints
• 3/8-by-5-inch lag screws (16)

Siding

• 10-foot-long 1×8 cedar shiplap boards (24), for front and rear walls
• 12-foot-long 1×8 cedar shiplap boards (24), for side walls
• 2-inch galvanized siding nails

Roof Framing

• 6-foot-long construction fir 2x4s (12), for rafters
• 5-foot-long construction fir 2x4s (6), for collar ties
• 4-foot-long construction fir 2x4s (6), for rear rafters
• 12-foot-long pine 1x8s (2), for roof eaves
• 12-foot-long pine 1x4s (17), for sheathing
• 2-1/2-inch screws
• 3-inch galvanized decking screws

Skylight

• 4-foot-long pine 1x2s (2), for side ledges
• 6-foot-long clear cedar 2x4s (2), for skylight curb
• 4-foot-long clear cedar 2x4s (2), for skylight curb
• 1/2-by-5-inch metal straps (4)
• 30 feet of 1/8-by-1/2-inch glazier’s tape
• 48-by-73-1/2-by-1/4-inch sheet of Plexiglas, for skylight
• 73-1/2 inches of 2-by-2-inch aluminum angle bar, for skylight top
• 48 inches of 2-by-2-inch aluminum angle bar, for skylight sides

Trim

• 14-foot-long cedar 1x4s (2), for gable trim
• 12-foot-long cedar 1x4s (2), for front and rear fascia
• 14-foot-long cedar 1x2s (2), for gable trim
• 12-foot-long cedar 1x2s (2), for front and rear fascia trim
• 7-foot-long cedar 1x4s (4), for front corners
• 5-foot-long cedar 1x4s (4), for rear corners
• 12-foot-long pine 1x2s (2), for eave trim
• Roll of 6-inch-wide insect screen, for eaves
• 38-inch-long pressure-treated 2×4, for pent above door
• 71 inches of 2-3/4-inch cedar casing (2), for door casing
• 36 inches of 2-1/4-inch cedar casing (6), for window jamb casing
• 30 inches of 2-1/4-inch cedar casing (3), for casing above windows
• 1-inch galvanized roofing nails

Finished Roofing

• 8-inch-wide aluminum roll, for flashing
• 18-inch red cedar shingles (7 bundles)
• 12-foot-long cedar 1x4s (2), for ridge cap
• 3d galvanized roofing nails

Door

• 6-foot-long 1×8 cedar shiplap boards (5), for door
• 6-foot-long pine 5/4×8, for battens
• 5-foot-long pine 5/4×4, for brace
• 1-3/8-inch #10 flathead wood screws (24)
• 10-inch-long strap hinges (2)
• Door latch hardware

Windows

• 10-foot-long clear cedar 2x3s (3), for window rails and stiles
• 10-foot-long cedar 1x6s (3), for window frames and muntins
• 30-5/8-inch-long pressure-treated 2x6s (3), for windowsill
• 1/8-by-20-by-29-inch sheets of Plexiglas (3), for windowpanes
• Brads
• Clear silicone caulk
• Window catches (3)
• 1/2-inch screw eyes (3)
• 1/8-inch-diameter nylon cord, 24 inches long (3)

Wall Framing

From the 4x4s, cut four corner posts 691/2 inches long, and two rear posts 56 inches long. Use 1x2s to temporarily prop up the posts while toenailing them to the floor.

Notch the ends of the 10-foot and 8-foot 4×6 beams to form lap joints. Position the 10-foot beams on the tops of the corner posts, and nail a 6-inch spike through each beam into each corner post.

Fit 8-foot beams into the notches in the 10-foot beams, and “spike” again. Cut ten 2-foot knee braces, and then miter-cut the ends at a 45-degree angle. Install braces at each corner using 3/8-by-5-inch lag screws.

Install 4×4 posts for the door frame. The doorway posts should be 32 inches apart. Cut ten 2×4 studs, measuring 69-1/2 inches long each. Install window studs, spaced 25-5/8 inches apart. Install interior wall studs, spaced approximately 24 inches on center. Install rough sills using screws (to allow for adjustments). Check for plumb.

Siding

The walls are covered with 1×8 shiplap boards. Rough-sawn cedar works well for this, because it’s rot-resistant and weathers to a soft gray. Start installing the siding at the bottom of each wall using 2-inch galvanized siding nails. To prevent rain from entering the shed, make sure each successive board overlaps the one below.

Roof Framing

Cut the tops of the 6-foot roof rafters at a 40-degree angle. Using the shed floor as a work platform, lay two rafters down flat, and join the tops using 2-1/2-inch screws.

To mark the location of the bird’s mouth, temporarily lay an 8-foot 2×4 (representing the width of the shed) approximately 6 inches up from the bottom end of each rafter, and mark with a pencil. Cut the ends of the collar ties off at a 40-degree angle. Screw the collar ties to the rafters, making sure the ends don’t protrude past the outer edge of the rafters, so as not to interfere with roofing. Cut bird’s mouth notches, and screw each pair of rafters to the top beam. Use a 1×4 to temporarily hold the rafters in place. Hold the end of one 4-foot rear rafter up to an existing rafter end and rear beam, and mark where the next bird’s mouth and rafter joint should go. Cut out the notches, and screw the rear rafters in place with 3-inch galvanized deck screws. To provide a base for the cedar shingles, nail a 1×8 to the bottom of the rafters, overlapping the bottom edge of the rafters by 3/4 inch. Space the remaining 1x4s 2 inches apart.

Skylight

Screw 4-foot-long 1×2 side ledges to sides of rafters 6 feet apart, with upper edges aligned. Build a “curb” out of 2x4s that measures 46-1/2 by 73-1/2 inches, and then screw it directly over the existing rafters, placing sides over side ledges. Headers aren’t necessary here, because the rafters remain intact. Bend over four 1/2-by-5-inch metal straps to form J-hooks, and screw them to the bottom of the curb to hold the bottom edge of the Plexiglas.

Lay glazier’s tape over the top edge of the skylight curb.

Carefully lay a piece of Plexiglas on top of the glazier’s tape. The Plexiglas and J-hooks should overhang the curb by 1 inch to allow for water runoff. After the skylight is installed and you’re shingling the roof, make sure to use stepped flashing where shingles meet the skylight curb. Once shingling is finished, complete the skylight by screwing aluminum angle bar to the sides and top.

Trim and Roofing

Trim the two gable roof ends with 1×4 cedar. Nail the ends of the spaced sheathing to the top of the gable trim. Add the front and rear 1×4 fascias, the 1×2 gable trim, and the 1×2 fascia trim, in that order. Cover the four corners with two 1x4s nailed to each other and to the walls. Attach the eave trim and insect screen.

Install flashing. Cover the 1×4 spaced sheathing with cedar shingles. Use 1-inch galvanized roofing nails. Double the first row of shingles, and overhang the edge of the roof by 3/4 inch. Stagger each row so the seams are unaligned. Make each row 5-1/2 inches above the previous one, using a 1×6 board as a guide on which to rest the bottom of the shingles before nailing them in place. Cap off the ridge with two 1×4 beveled boards caulked and nailed together.

Door

On a flat surface, place the shiplap cedar boards side by side. Saw off the edges on the two end pieces so the door measures 32 inches wide. Cut two pieces of 5/4×8, each 31 inches long, for battens. Screw the battens to the door. Mark and cut the 5-foot-long 5/4×4 as a diagonal brace to fit between the top batten and the hinged side of the bottom batten. Screw two 10-inch strap hinges to the front of the door.

To hang the door, screw the other half of the hinges to a piece of 2-1/4-inch cedar door casing. Hold the door in place, and, allowing for a 3/16-inch clearance, screw the trim and the door to the shed. Add the pent roof and the 2-1/4-inch casing to the doorway. Install door latch hardware of your choice.

Alternatively, A wooden latch can be made from a piece of 1×2, two pieces of 2×3, and a 1/8-inch diagonal dowel. Cut a 1-1/4-by-3-inch slot in the door for the dowel to extend to the exterior. Mount the latch on a piece of 5/4×8, and screw it to the inside of the door.

Windows

For each of the three windows, cut two 33-inch-long pieces of 2×3 for the stiles and two 22-inch-long pieces of 2×3 for the rails.

Using a table saw, make a 7/8-by-1-1/2-inch rabbet cut in one edge of each 2×3. Cut a 2-1/2-inch shoulder notch in each end of the 33-inch 2x3s. Make a 5/8-inch-wide, 5/8-inch-deep dado cut in the middle of each 2×3 to accept the muntins, which you’ll add later.

For each window, glue and screw the sash together using 2-inch screws. Lay a bead of clear silicone in the rabbeted groove provided in the window, and insert a Plexiglas panel into the groove. Use brads to nail waste strips (left over from cutting the rabbets) over the edges of the Plexiglas to hold it in place. Cut and glue 5/8-by-5/8-inch muntin strips to the front of the window. Install a window catch to the top of the window.

To hang a window, build a 4-3/4-inch-wide window frame to fit inside the rough opening, allowing 1/8 inch of clearance between the window and the frame. On the 30-5/8-inch-long windowsill, bevel the front and back edges at a 15-degree angle. The windowsill should extend 1/4 inch past the outside edges of the 2-1/4-inch casing. Install the sill over the rough opening. Cut the bottom ends of the two window casings at 15 degrees to fit the sill, and nail them in place. Frame the inside and outside of the window opening with 2-1/4-inch casing. Mortise a small hole for the window catch bolt, and install a screw eye and cord to hold the window open. To keep the window in place, cut and nail 3/4-by-3/4-inch stops to the side window frames. Open the window by releasing the catch and tilting it back. No rain will get in, and the window can be easily removed for maintenance. Repeat with the other two windows.

Excerpted with permission from Sheds: The Do-It-Yourself Guide for Backyard Builders, 4th Edition, by David and Jeanie Stiles.