Haun_Larry_-_The_very_efficient_carpenter

other, lapping them about 3 ft. Make sure the two pieces lie in a straight line and make a diagonal cut across the lap. Cut the bottom board by following the saw-kerf mark left from the first cut, then nail the two long pieces together to form one board. Nails can be driv­ en down through the edge and toenailed into the sides. Make this splice as near to the ridge cut as pos­ sible so that it can be braced off a wall with a leg or post under it once it is nailed in position.

Dropping the Hip

3. Fromthis point, square uptothe top edge of the rafter stock and mark a second level line. The distance between the two level lines is the amount that the hip rafter needs todrop.

/j\ The seat cut is

dropped this amount.

Laying out and cutting hip jack rafters

Hip jack rafters are usually cut from the same size

Laying Out Hip Jack Rafters

Hip jack rafters

Chalkline aligns with heel cut.

Tailsare cut to length after roof is stacked.

Common difference

(167/8in. for 4-in-12 pitch with 16-in. o.c. rafters)

JACK-RAFTER TABLE

4-in-12 pitch (18V2° angle)

Jack-rafter side cut

Each pair of jack rafters is cut in opposing directions, with saw set at 4SO

Plumb side-cut mark

Full-length

Hip jack rafters need the same length of tail as

commons, so measure up from the flushed tail ends and make a mark across the edges of all the stock

and mark the heel cut. Rafter tails are usually cut to length after they are stacked, so at this point they need to be left at least 2 in. or 3 in. longer than needed. Next, from the ridge plumb cut of the un­ shortened common, measure back the common dif­ ference on the first set of jacks. Shorten this set of jack rafters one-half the 45° thickness of the hip (1Y16 in. for a 2x), and mark this length across the top edge of all the jacks in this set. Make a diagonal mark to indicate the direction of the side cut for each pair of jacks that nail to opposing sides of the hip or valley. Measure down the common difference and mark the next set, and so on. Using the common-rafter template (see the side­ bar on pp. 140- 1 41 ), mark the plumb side cut and the bird's-mouth cut. Because the jack rafters are in pairs, the plumb cut at the hip is laid out on alter­ nating sides of the rafter stock. Make the cuts and stack the jacks in appropriate

piles so they can be carried to the corners and placed up on the ceiling joists. The shorter jacks can be hung from the double top plate by a 16 d nail

driven into the side cut. Some experienced framers have developed a shortcut for cutting jacks. They make one plumb ridge cut work for two jacks. This is done by using stock that is long enough for both the longest and

shortest jacks. Layout the longest jack with the bird's mouth on the top edge of the stock and the shortest with the bird's mouth on the bottom edge,

as shown in the drawing above.

Stacking a hip roof A basic hip roof is put together much like a simple gable roof. Run a 16 -in. or 24-in. on-center layout, as called for on the plans, on a section of ridge. Bring up the two opposing commons next to the king-common layout at the hip end and nail them to the plate and joists at the building line. Then go to the end of the ridge board and nail in two more

commons. Bring the ridge board up between the two sets of common rafters and nail it in place, leav­

ing 16 in. to 24 in. sticking out on the hip end to receive the king commons (see the top drawing on p. 16 8). There is no need at this point to worry about trying to calculate the exact ridge length­ this is more easily done when it's time to nail in the

end king common. Make sure the ridge is level (see p. 150), then cut 2x posts to put under each end to hold it in place. Plumbing the rafters is easy on a gable roof because the end of the building is the reference point. On a hip roof, the commons can be plumbed off a paral­ lel joist and held in position with a sway brace. On most roofs, common rafters tie to parallel joists to form the roof truss. If the commons are directly alongside and in line with the joists, then they are plumb. You can check this with a level, or you can do what a lot of experienced carpenters do-stand up straight and sight the rafter parallel with the joist by eye. This method may not be perfect, but if it

looks close enough, nail it. A long building will need several sections of ridge. These can now be set between commons and held level at the proper height by posts. At each ridge end, bring up an end king common, hold it alongside the ridge, and mark and cut the ridge to length. Nail the end common to the ridge end and the wall plate. It, too, now functions as a sway brace.