After assembling the walls of YZY granny flat, the next step is to install the gables.
When building the walls above the windows, you will find that there is a gap between the frames and upper wall-boards. You might be worried about the cavity around the door and window frames. If this is the case, please don’t panic, everything is ok.
Important: Do not worry about the space left around the windows and door frames. It is essential for natural timber movement, expansion and contraction. Do not try to fill the space! There must be a cavity left around the windows and door frames, minimum 5 mm to the sides and 25-30 mm to the top as structure will settle down.
Assemble the gables according to the drawings. Gables are usually marked with letters A, B, C etc. that match the letters of the walls. Make sure you have gables located correctly. You will have to screw off the gable pieces with quite a long about 10 or 12 gauge screws.
Experts Tip: “We recommend you to go around 50 to 70 mm off bite into the bottom board. So, line your screw up, mark it on top, grab a drill and just drive them in. And it’s important to sink the screws down bellow the surface so they do not protrude into the ceiling boards.”
Now that the gable pieces hold nice and firm you can put your rafters in. Roof rafters will lock the gables into place and the whole building will become structurally sound and solid. Before installing rafters or after, it is important to make sure building is square and plumb. All granny flat building steps can be found on Builders Guide page.