Lay your 4 x 4 skids lengthwise of the building. Buildings over 12' long will have more than 1 skid for each length.

For 10' wide buildings and up you will have three or four runs and they can be spaced as you prefer. typically we like the outside skids flush to the outside of the floor and then one centered.

Your floor joist (short treated 2x4) will run crossways perpendicular to the 4x4.
Fasten your floor joists to the longer treated 2x4 (rail) spaced evenly 16” or 24” inch centers measured from the end with a joist at each end. (Some customers upgraded to 12 inch centers)( 10’ wide and wider is 16" on center)

Toenail to your 4 x 4 and level with blocks or pavers. If you would like to put support blocks between each joist you can cut them out of scrap 2 x 4 you May have laying around.

Follow the instructions above for the wood floor, but disregard the 4x4 skids. You'll need to screw the joists directly to the rail instead of nailing them.

Lay out your tongue-and-groove (T&G) sheathing ahead of time so you can plan how it will fit together.

If you're working with only 4-foot-wide panels, start by placing the first sheet with the tongue side facing outward, flush with the outside of your floor rail.

If you have 2-foot-wide panels (commonly used on 10-foot or 14-foot wide buildings), check whether the edge has a tongue or a groove:

If it's a groove, use those panels for your first row, with the groove facing away from the rail.

If it's a tongue, save them for the final row so they can slide into the grooves of the previous sheets.

Once your floor frame is squared and level, secure the sheathing to the joists with nails or screws.

Wall panels are typically 12 feet or shorter. If your sidewall is longer, it will come in sections that overlap—one panel will have siding that extends out (overlap), and the other will have siding tucked underneath (underlap) with a stud offset halfway at the end for connection.

Sidewalls run the full length of the shed, just like the 4x4 skids under the floor. End walls fit between the sidewalls and include 3½" of siding
overhang on each end.

Once positioned, nail or screw the bottom plate to the floor—aim for joists and the floor rail through the sheathing. If you plan to relocate the shed later, use screws for easier disassembly.

Gable Ends

Stand your gable end panels upright and center them on the end walls.
Secure them by nailing or screwing through the wall’s top plate into the gable’s bottom plate.

Rafters

To install your rafters:

Barn-style sheds: Fasten rafters flush with the outer edge of the wall plate. You can nail up through the top plate from inside the shed. If a stud is directly below the rafter, angle the nail to avoid hitting it squarely.

Ranch-style sheds: Install the side eave overhangs after the gables but before the rafters. This lets you align the rafter tails with the gable peaks and the outer edge of the side eave trim (usually ¼"–½" inside the trim).

Fasten the side eave from inside the shed by angling screws or nails through the siding. Make sure the top of the eave is flush with the top of the wall plate.

For barn-style sheds, start by installing the lower gable roof trim ½ inch above the gable framing so it sits flush with the roof sheathing once applied. Let it run long for now—you can trim it flush after the side eave is installed. Then install the gable-to-wall trim, which may need to be cut to length (the angle is already cut for you).

For ranch-style sheds, trims are typically pre-attached unless extended roof overhangs were ordered.

If extended gable overhangs were included, you’ll need to install the soffit before applying the gable-to-wall trims.

For barn-style sheds, it's easiest to install the top level of roof sheathing first while standing on the wall. Keep the sheathing square and try to align the factory-painted edges whenever possible. Rafters are spaced 24 inches on center, and you may need to flex them slightly so the roof’s pitch transition lines up with the bottom edge of the upper sheathing. Laying out the panels on the ground ahead of time can make the process smoother.

Once the lower sheathing is in place, push the side eave up against the bottom edge and fasten it to the building—ideally into a wall stud for added strength. You can also drive fasteners through the sheathing and into the top plate of the wall for extra support.

For ranch-style sheds, begin at the low point of the roof and attach the sheathing to both the side eave and the rafters. Ensuring the panels are square will help each subsequent row align correctly. Always try to match factory-painted edges, and confirm rafters are spaced 24 inches on center with the sheathing edges centered on the rafters before nailing.