Gambrel Roof Building

Build the exterior building walls. These walls will consist of a bottom plate, studs spaced per building code on the center, your corner post per plan, windows with headers if in plans, doors with headers if in plans, and a top plate. When you have this laid out in front of you as per your blueprints, you will nail it together using sinker nails by either hammer or a pneumatic gun. Once nailed together, raise the walls and nail them together to form your exterior walls. Place braces for support around these exterior walls to keep them from falling. Once you have braced these exterior walls, go around with a ladder and place another top plate--this is known as a double top plate.

Lay out your joist. Joist are usually the same spacing as your studs so all baring weight is placed on the studs. Joist can be either solid pieces of lumber such at 2 x 12 board, or they can be manufactured. Solid joist will be nailed directly into a sill plate sitting on top of the double top plate. Manufactured joist, such as I-beams, will use joist hanger as well as hangers that are nailed directly to an APA performance board that sits on top of the double top plate. Lay out lines so that they are center to the studs of your exterior walls. Use a cut off of an I-joist to make sure that you have enough space to slide in your I-joist when installing the I-Joist into the hangers. When you are finished with the joist, you will lay down and nail plywood directly to the joist for a sub floor.

Build your lower slope and upper slope common rafters. The lengths of both upper and lower slope common rafters will follow the unit run by unit rise math. Mark the ridge plumb cut line on your upper slope common rafter. Next, shorten this cut line by half the thickness of the ridge board. Measure rafter length from original plumb cut line, the first line you made, and mark the seat cut line. For the notch over the double top plate, measure width of plate along seat cut line and mark another plumb cut line. Do this to all upper slope common rafters and cut. For the lower slope common rafter, it is almost the same as the upper slope common rafter but with different measurements. Mark a plumb cut line at the upper end of rafter, and then measure total rafter length from plumb cut line and mark the heel plumb cut, seat cut and overhang lines.

Find the center of your sub floor and measure out the location of the partition walls. Frame these walls in the same way as the exterior walls. Nail the walls together with the studs spaced per blueprint plans. Next, nail the second top plate to make your double top plate and then raise the walls, making sure to brace them first. Lay out the lower slope common rafter per plans and nail then down. Next, install your upper slope common rafters with the ridge board at the top per blueprint plans. While doing this you will also nail in the collar tie per plans or about every third rafter.

Position the plywood where required and nail throughout the exterior of the gambrel building and on the roof. Space the nails about every 3 to 5 inches apart all around edges of the plywood, and about every foot where ever the center of plywood touches studs. Make sure to layout plywood and cut for windows, doors and any other openings throughout the building.