Build this Modular Shed

Most homebuilders use trusses for three good reasons: They're strong, easy to install and reasonably priced. This truss-inspired shed offers the same advantages. Once the floor is built, you'll use it as a template for "manufacturing" combination wall-roof trusses. After you stand up the trusses, the basic framework is done.

Further simplifying construction (and saving time and money), T1-11 sheet siding acts as both structural sheathing and finished exterior.

Build the floor
First stake out the location of your shed; then remove 4 to 8 in. of soil 1 ft. beyond the stakes in every direction. Haul in washed gravel to create a bed about 6 in. deep. Level the gravel to create a flat surface. Do it right; your shed will only be as level as this base.

Build the perimeter of the floor using treated timbers (A, B) as shown in photo 1. Secure the corners using metal straps on the tops and sides. Check the perimeter for level and measure the diagonals. If it's not square, whack one of the long corners with a sledgehammer until the measurements are equal. Tamp the timbers down with a sledgehammer so they make solid contact with the gravel.


With the timbers in place, add the floor joists (C) and blocking to create a solid base for the shed. Then use construction adhesive and exterior-rated screws to secure the plywood floor sheathing.

Measure from one end of the floor perimeter to the other, marking 2-ft. increments to indicate the centers of the floor joists. Install joist hangers and the joists (C). Add blocking at the midway point. Run a bead of construction adhesive down the middle of each floor joist and rim joist. Position a sheet of treated-plywood floor sheathing (D) in one corner and secure it to the joists with 2-in. exterior-rated screws. Install the rest of the floor sheathing, making sure the seams are supported by the blocking.

Build the trusses
Cut two wall studs (E) with 45-degree angles on one end, one crosstie (G) with 45-degree angles on both ends and two rafters (F) with 45-degree angles on one end as shown in "Truss Detail," p. 34. (Note: Wall studs can be anywhere from 7 to 8 ft. long.) Position the wall studs on the platform so the ends and sides are even with one end and the sides of the platform. Position two roof rafters, making sure the peak is centered and the eaves extend equally past the studs in both directions. Position the crosstie.

Stand back and ponder. Do all of the components fit tight and symmetrically? When you measure from the bottoms of the wall studs to the peak of the rafters, are the measurements equal in both directions? If so, use a felt marking pen to trace along the edges of all members to create a template on the platform for building the remaining trusses. Take one rafter, one wall stud and the crosstie and mark "pattern" on each. Use them to mark and cut the rest of the wall studs (E), rafters (F) and crossties (G). Make the gusset plates (H, I) by marking a sheet of 1/2-in. plywood and then cutting out the pieces (see illustration below). Use a straight-cutting jig to cut the plywood lengthwise; then use a circular saw or miter saw to cut the pieces to the correct angle and length.

Click here for a large, printable illustration of the gusset plates.

Straight-cutting jig

Watch this video about creating a jig for making consistently straight cuts in long pieces of plywood.

You're now ready to go into truss-manufacturing mode. Position the five components for one truss on the shed floor, tack them together with one 8d nail at each joint. Apply construction adhesive to the areas where the wall studs, crosstie and rafters meet; then nail the crosstie gusset plates (I) in place, driving at least four 1-1/2-in. shingle nails in each member. Do the same for the peak gusset plate (H).

With the assistance of a helper, flip the truss over and install another set of gusset plates on the other side. Move the truss off of the platform and repeat this six more times. Note: The two outer wall trusses of the enclosed space have gussets on only one side; the gussets get in the way of the siding if you put them on both sides.

Lay the bottom wall plates (J) and eave plates (K) side by side as shown in photo 2, p. 33. The eave plates will extend past the bottom wall plates by the length of the roof overhang — anywhere from 12 to 24 in. Measure from one end of the bottom wall plates and make marks on the plates every 2 ft. to indicate the centers of the trusses. Make marks to indicate the edges of the 2x4 trusses; then transfer these marks across all four boards. Secure the bottom wall plates (J) to the long edges of the platform with 16d nails. With a helper, stand one end truss and nail the bottoms to the bottom wall plates. Install braces to hold this end truss plumb. Stand the other end truss and brace it, too.


Lay out the eave plates (K) and the bottom-wall plates (J) together. Make marks on the plates every 2 ft. to indicate the centers of the trusses. Transfer these marks across all four boards.

Secure an eave plate (K) to the two end trusses (photo 3). It will extend past the trusses the length of the overhang. Install the rest of the trusses (photo 4), securing them to both bottom wall plates and the eave plate. Once all of the trusses are in place, install the other eave plate (K).


Secure the bottom wall plates to the long edges of the platform. Stand one end truss and toenail the bottoms to the bottom wall plates. Install braces to hold this end truss plumb. Stand the other end truss and brace it, too. Then secure an eave plate to the two end trusses as shown. The eave plate will extend past the trusses the length of the roof overhang.


Install the rest of the trusses, securing them to both bottom wall plates and the eave plate. Enlist the help of a friend for this step, as it's challenging to carry the trusses and hold them in place while you nail everything together. Once all of the trusses are in place, install the other eave plate.

Frame the end walls
Secure nailing plates (see "Wall and Roof Framework," opposite) to the floor for the back wall and the front wall. To create the front porch, install the nailing plate 4 ft. back from the front of the platform (flush with the front of the truss positioned there). Cut the end studs (L) and install them so they're flush with the fronts of the crossties (G) and bottom wall plates (J). For the door opening, leave enough space for the rough opening designated by the door manufacturer.

For the window, add horizontal 2x4s to create the rough opening (photo 5).


Be sure to purchase your window prior to framing the window opening. Choose a window that is less than 22 in. wide so it will fit easily between the trusses.

Sheathe the walls and roof
Measure the spacing of the rafters at the top of the wall; then cut notches (about 1-1/2 in. wide x 5 in. deep) on the top edge of the T1-11 siding. The notches allow the siding to fill the gaps between the tops of the wall and the bottom of the roof sheathing. Trim the bottoms of the siding sheets so they extend at least 3 in. down on the perimeter beams, but keep them at least 2 in. above ground level. Paint or stain the T1-11 siding and trim for protection from the elements.

Fasten the siding in place with 8d galvanized nails every 6 in. along each wall stud (photo 6). Measure, cut and fit the end wall siding. Install Z-flashing along the top edge of the lower sheets before installing sheets above.


Cut the siding to size and lift it into place. Check out the "Working Alone" video (below) for quick tips on completing this step while working alone.

Working alone

Watch this video about how to lift and hold large pieces of material in place when you're working alone.

Install the first row of the roof sheathing (N) so the lower edge is even with the edge of the eave plate (K) and the ends break in the middles of the rafters; then install the rest of the plywood.

You'll need to install fly rafters (see illustration in PDF) to support the overhangs on the ends. (You should have four rafters left from the parts you cut.) Secure the peaks of the fly rafters to one another; then nail the rafter ends to the ends of the eave plates (K).

Complete the final steps
Install the window and door; then secure 1x4 and 1x3 trim at the corners of the shed (photo 7) and around the window. Caulk all seams.


To add a finishing touch, install 1x4 and 1x3 cedar trim on the corners of the shed and around the window and door. You can paint or stain the trim to complement the color of the shed siding or the exterior of your home. We chose white for the trim to match the color of the porch and painted the siding with Behr Marquee exterior paint in a color called Inked.

Install Style D (also called drip-edge) flashing along the perimeter of the roof to cover the exposed edges of the roof sheathing. Staple tarpaper to the roof; then install the roofing. We chose low-maintenance DaVinci Bellaforte polymer shakes in Espresso for their appearance and durability (photo 8). All shingles come with specific installation directions; be sure to follow them.


To make life easier down the road, we chose to install DaVinci Roofscapes' Bellaforte roofing tiles on this shed. The tiles are low-maintenance yet resemble natural shake tiles. Check out davinciroofscapes.com to learn more.

Finish up the shed by coating the porch area with porch-floor paint for a long-lasting, durable surface.

This project is featured in Spike Carlsen's The Backyard Homestead Book of Building Projects from Storey Publishing. The book contains complete plans for raised-bed gardens, PVC greenhouses, garden carts, chicken coops and 70 more great projects for greater self-sufficiency.