DIY Dog House: Roof

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Intro | Drawing & Materials ListFloor and Walls | Deck

Ridge Pole and Rafters

With the front and rear outer walls temporarily attached to the side walls with a couple of screws or pipe clamps, cut a ridge board for the roof that spans the distance between the front/rear walls. Position the ridge board so that is centered at the peak and hold in place with a pipe clamp (Figure 1). Now you can layout and cut the rafters.

Figure 1. Temporarily attaching ridge pole.

To establish the top angle for the rafters, clamp a scrap piece of 2×3 material to the inside of the outer wall and with a square held against the ridge board, mark the cut line on the wood scrap (Figure 2). Use the same approach to layout the bottom angle, this time placing the square against the side wall. Also measure the distance from the outside of the side wall to the top edge of the ridge — this represents the length of the top edge of the rafter. It should be about 18″ more or less.

Figure 2. Laying out the top angle for the rafters.

With the rafter angles and length established, cut out the rafters with your miter saw. I recommend first cutting the bottom angle on all the rafters. Using one of these pieces as a template, measure up from the cut end and mark the location of the top cut. Then set the miter saw for the top angle and cut the template slightly long. Gradually sneak up on the layout line until the rafter fits snugly in place. (If you’ve done things correctly, the top and bottom cut lines will form a right angle when a square is placed against them). Finally, set a stop for your saw and cut the rest of the end rafters to final length (total of 4).

Figure 3. Test fitting rafters.

Clamp the end rafters in place as shown in Figure 3 and screw the top of each rafter to the ridge beam. You may want to drill a countersink so as not to risk splitting the material. Also secure each end rafter to the wall using 1-2 screws inserted from the outer wall. These will hold the structure in place for the rest of the assembly (the clamps would be in the way when the roof panels are attached).

The two inner rafters are cut slightly shorter than the end rafters because they butt up against the concealed fascia boards that run along the base of the roof frame. These boards enhance the structural integrity of the removable roof. With the end rafters clamped in place, cut two fascia boards that span the distance between the rafters. Position each fascia so that it rests against the top of the side wall and is in the same plane as the rafters (See the pics). Then measure the distance between the top edge of the fascia and the ridge beam — this will define the length of the inner rafters. Mark and cut the inner rafters.

Figure 4. Roof frame depicting end rafters, inner rafter, concealed fascia, and ridge.

At this point, all of the roof framework should be cut to size. Toe screw the end of each fascia into the end rafters. Do the same for the inner rafters. A single screw at each joint will suffice for now — additional screws can be added later when the frame is removed to install the insulation panels.

Figure 5. Close-up view of roof joint.

You’ll notice in the photos that the inner rafters are not actually in the middle of the roof. This is because I used two pieces of plywood for one side of the roof and positioned the inner rafter to line up with the point where the two pieces met. For the sake of symmetry, I also offset the other inside rafter.

Roof Panels and Insulation

The next step is to create the two exterior roof panels. Each is 22″ wide by 39″ long, which allows for about 3″ of overhang all around. It’s best if each panel is a single piece of plywood. However, I ended up using two pieces for one side because I

Figure 6. Side view of roof with front wall removed.

wanted the grooves in the T1-11 plywood to all line up and run vertically, and I didn’t have enough large pieces left – with the proper groove orientation – to use a single piece for each side. If you plan to cover the roof with shingles, it should be much easier to find two whole pieces of plywood since you won’t care if the grooves line up or not.

Alright, enough rambling… Do what you must to come up with two roof panels of sufficient size. Rip each to rough width and cut to finished length. The ends where the two panels meet at the peak of the roof should be cut at an angle so the panels fit tightly together. This angle is the same as the top angle of the roof rafters. Transfer this angle to your table saw and cut two pieces of scrap wood to see how they line up. Adjust as necessary and when the angle is correct, go ahead and cut each roof panel.

Position the roof panels on top of the roof frame. When you’re satisfied that they meet tightly at the peak and overhang evenly on the front/back, remove one of the panels and clamp the other in place as shown in Figure 4. (It helps to have an assistant for this operation). Then insert a few screws into the clamped panel to attach it to the frame. Remove the clamp and attach the other roof panel in a similar manner.

Figure 7. Underside of roof with insulation panels in place.

Now it’s time to work on the interior roof panels. For these, I used some 1/4″ thick material that I found on the woodpile. Remove one of the end walls as shown in Figure 5 and measure the distance from the peak to the side wall, with the tape measure held against the bottom edge of the roof rafter. This distance represents the width of the interior panels. (Actually, one panel will be slightly narrower than the other – by the width of the plywood – because it will butt up against the other panel). Measure the panel length also – it should be the same as the length of the side wall panels. Cut the two panels to size and check their fit. Don’t get too mental if the panels are a little undersize – only the dog will ever see it.

Figure 8. Close-up view of ridge beam and rafters.

Remove any screws securing the roof to the walls and with the help of your able-bodied but underpaid assistant, pick up the roof and place it upside down on the workbench.  Cut out four pieces of foam insulation panel to fit inside the roof frame and tape in place (Figure 7). Then screw on the interior roof panels. This is also a good time to insert additional screws to better attach the outer roof panel to the frame. I recommend toe-screwing them from the inside rather than putting holes into the top of the roof.

Figure 9. Roof flashing.

Ridge Cap

The last step is to attach a ridge cap. It not only enhances the appearance of the house but helps to keep water from getting into the roof panel joint and really stiffens up the roof structure. I made a cap from 3/4″ x 3-1/2″ cedar with a piece of 6″ wide flashing underneath it (Figures 9-12). To reduce the opportunity for water to get into the joint,

Figure 10. Layout diagram of roof cap.

I ripped one edge of each cap piece at a 16.5 degree angle (to match the pitch of the roof) and then put in 3-4 screws to attach the pieces to each other.  The completed cap is then screwed onto the roof with a half dozen screws or so.

Figure 11. Ridge cap in place.

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