Siding With Plywood

Plywood siding is sturdy, economical, and easy to install. Designed to face the elements, it comes in various lengths—but 8 feet is most common—and in a variety of textures and patterns. It is also available with shiplap edges that mesh with adjoining panels.

If your studs are 24 inches apart, make sure the paneling is the thicker kind designed for this spacing. When ordering the paneling, ask your supplier for Z-flashing to fit between the end-truss siding and the wall siding.

Safety Tips: Wear goggles when nailing.

1. Fastening the First Panel.

Starting at a corner, apply exterior caulk to the stud surfaces that will contact the first panel.

Slip one flange of a piece of Z-flashing behind the sheathing that covers the end truss, then ease the first siding panel behind the other flange (inset).

Secure the panel to the studs with galvanized box nails long enough to penetrate the studs by 1 inch. Space the fasteners 6 inches apart along the starting stud and at 12-inch intervals along the other studs. Rather than driving nails through the lapped edge of the panel, apply caulk along the lap (left).

2. Finishing the Job.

Install the next panel so its lapped edge meshes with the first. Avoiding the joint, nail the edge of the second panel to the stud (left); this will leave the first panel free to expand.

Install the rest of the siding this way. Trim the corner panels and Z-flashing as needed using tin snips to cut the flashing.

Cover the exposed edges of the siding at the corners with 1-by-3s and 1-by-4s fastened with 2 1/4-inch galvanized finishing nails (inset).

A Cottage of Prefab Panels

This cottage has standard stud walls covered with siding (below). An advantage to this structure is that its walls can be prefabricated in sections, hauled to the site in a small truck and, with three or four helpers, quickly assembled on the floor of the cabin and topped with a simple rafter or truss roof.

Planning

To ensure that the sections fit together properly, draw a scaled plan of the structure before building the panels. Indicate the size of the foundation and the location and dimensions of walls, doors, and windows. You can simplify construction by ordering doors and windows that fit between studs (opposite). If you are planning to build your cabin with a shed roof, you’ll need to make the back wall higher than the front, or one side wall higher than the other.

Wall Panels

The wall frames are built in multiples of 4 feet—a size that suits common building materials. The economical cabin shown in this excerpt uses 8-foot exterior siding, and has ceilings just under 7 feet high. If you want higher ceilings, cut the wall studs longer and buy 10-foot siding—which costs a bit more—and trim it to length. Place the assembled panels on the truck in order so that the last one you load is the first to be erected; this way, you can unload and assemble the walls in sequence.

Anatomy of a Prefab Cabin

This cabin has wall panels in three sizes. The basic panels are 8 feet wide, the filler and corner panels are 4 feet wide. Modified basic panels at each corner provide a nailing surface for the end stud of the adjoining corner panel. The wall sections are nailed together where they abut, and connected by an overlapping top plate, installed on site. Interior partition walls are framed the same way as the exterior walls, which have blocking where the partitions adjoin them.

The Basic Panel

Each panel is made from seven 2-by- 4 studs cut 6 feet 9 inches long. The 2-by-4 top and soleplates are cut 8 feet long, and the studs are fastened to the plates at 16-inch intervals with the middle stud in the center of the panel so wallboard and interior paneling can be nailed there. Two pieces of 5/8-inch vertical siding are nailed to the studs and plates flush with the outside faces of the outer studs so they project above the top plate by 1 1/2 inches and below the soleplate by 10 1/2 inches.

Filler panels are made in the same way, but with four studs and one piece of siding, so they are only 4 feet wide. A basic panel can be adapted to accommodate a window or door as shown for the modified and corner panels below.

Modified Basic Panel

To tie walls together at a corner, an extra “nailer” stud is added—flush with the inside edge of the sole-plate—at the left end of a basic panel—when viewed from the outside—to serve as a nailing surface for the first stud of the adjoining corner panel. For a panel with a window opening, a header, made with 1/2-inch plywood nailed between two 2-by-6s, spans the top of the opening; jack studs nailed to the king studs at either side of the opening support the header; a rough sill is toenailed to the jack studs; and a cripple stud braces the rough sill.

A Corner Panel

The top and sole-plates of this panel are 7 feet 8 1/2 inches long, with the stud at the corner spaced only 12 1/2 inches from the next stud. The sheathing overlaps the corner end by 3 1/2 inches. When the panel is put in place, the overlapped siding attaches to the end stud of a modified basic panel. Because the siding always overlaps to the right when viewed from outside, erect the walls from left to right. A door opening is framed much like that of a window, but the rough sill and cripple stud are omitted.

Building Walls in Sections

1. Sizing the Studs With a Jig.

To make a jig that will enable you to cut several studs to length in a single operation, secure a plywood panel atop a pair of sawhorses with 2-inch common nails. With 3-inch nails, attach a 2-by-4 stop along one side of the panel, and a 2-by-2 stop along an end, perpendicular to the side stop. With a hinge, fasten a 2-by-2 guide at a 90-degree angle across the side stop and panel; locate the guide so that the studs will be the correct length when you run a circular saw along it. Swing the saw guide up and put the 2-by-4s edge to edge in the jig so they are butted against the end stop and the first board is flush against the side stop. Lower the guide in place. Holding the 2-by-4s steady, run a circular saw across the boards with the base plate against the guide (above).

2. Joining the Studs and Plates.

Cut the top and soleplates to length, then mark stud locations on one face of each board, placing the middle-stud mark in the center of each plate and the rest at 16-inch intervals. If the panel will have a window or door opening, space the studs on each side of the gap according to the rough opening required, plus 3 inches.

To join the studs and top plate, align the stud with its outline, stand on the board, and drive two 3 1/2-inch common nails through the plate into the stud (left).

Attach the soleplate the same way.

For a modified panel, add a nailer stud butted against the last stud and flush with the inside of the top and soleplates (inset). For a corner panel, locate the last stud at the corner 12 1/2 inches from the next one.

3. Framing a Rough Opening for a Window.

To make the header, first cut two 2-by-6s and a 1/2-inch plywood spacer of the same width to fit in the opening; sandwich the spacer between the 2-by-6s and secure the assembly with 3 1/2-inch common nails driven every 10 inches in a staggered pattern.

Cut two jack studs to fit between the header and soleplate, and fasten them to the king studs at each side of the opening.

Cut a 2-by-4 rough sill to fit between the jack studs and fasten it (above), spacing it from the header the distance indicated by the window manufacturer’s specifications.

Cut a 2-by-4 cripple stud to fit between the sill and soleplate, then nail it to both boards.

Frame a door opening in the same way, but omit the sill and cripple stud.

4. Jig for Fastening the Siding.

Cut a 2-by-2 stop 8 feet long and nail it along one edge of a plywood panel. Cut a 2-by-4 stop 3 feet 10 1/2 inches long and fasten it along an end of the panel. Cut two 1-by-6s to the lengths of the two stops; then, with 2-inch No. 6 wood screws, fasten one to the inside edge of the 2-by-4 and the other to the outside of the 2-by-2.

5. Adding Siding to Basic Panels.

Set the siding jig on the floor and place the panel on it so the top plate rests flush against the 2-by-2 stop and an outer stud sits against the shorter 1-by- 6 stop.

Place a sheet of 5/8-inch exterior siding atop the panel so one end and edge are butted against the 1-by-6 inch stops.

With 2 1/2-inch galvanized box nails, fasten the siding to the top and soleplates and studs, leaving 1/8 inch between panels and driving the fasteners at 6-inch intervals around the perimeter and every 12 inches along the studs (above).

If the panel has a window or door opening, turn it over and drill a hole through the sheathing at each corner of the opening. Join the holes with pencil lines and cut the siding along the marks with a saber saw.

6. Covering End Panels.

Modify the jig by moving the shorter 1-by-6 from the inside to the outside of the 2-by-4 stop (inset). Nail the siding to the frame (left).

7. Flashing an Opening.

With tin snips, cut a piece of 6-inch aluminum flashing to the width of the rough opening. Bend the aluminum over a 2-by-4 to a 90-degree angle, forming two flanges. Loosen the siding around the header with a cold chisel or pry bar. Slip one flange of the flashing between the header and the paneling (left), then nail the flashing and siding to the header.

Erecting the Panels

1. Bracing the First Panel.

Have two helpers hold a modified basic panel plumb at one end of the foundation, positioning the nailer stud at the corner. With 3 1/2-inch common nails, attach a 2-by-4 brace to the second stud, fasten a short board to the bottom of the brace, and nail the board to the subfloor (above). Fasten a brace at the other end of the panel to hold it plumb. Anchor the panel to the foundation by nailing its soleplate to the subfloor, driving a nail through the plate between each pair of studs.

2. Extending the Wall.

Position the second panel against the first. With a helper holding the panel upright, use a 4-pound maul to align it with the first (above).

Plumb and brace the second panel, then nail the abutting joists of the two panels together.

Repeat the process to raise three of the four walls, working from left to right (when viewed from outside the building) so each corner has a modified panel and an overlapping corner panel.

Bring the interior walls inside, then raise the fourth wall.

With 2-inch galvanized nails, fasten the sheathing of the corner panels to the nailer studs of the modified panels.

3. Tying the Walls Together.

Cut a 2-by-4 top plate 4 feet long and, with 3 1/2-inch nails, fasten it atop the top plate of a corner panel so it overlaps the top plate of a modified panel (left).

Continue in this fashion around the perimeter of the wall, nailing on 8-footlong plates that overlap the seams between adjacent panels. Cut the last 2-by-4 of each wall to fit against the adjoining wall.

Working outside, cover the exposed edges of the siding with 1-by-3s and 1-by-4s fastened with 2 1/4-inch galvanized finishing nails. Nail on the 1-by-4 first so it overlaps the corner by 3/4 inch, then attach the 1-by-3 flush against the 1-by-4.

Raising Partitions

4. Locating the Wall.

With a helper at each side wall, snap a chalk line across the subfloor at one side of the proposed wall. To locate a wall directly above the girder, measure the distance between one foundation wall and the girder from below the floor, then transfer the measurement to the floor. Snap a parallel line 3 1/2 inches from the first (left).