Fig. 88-b. Fig. 88-c.
Side Cuts of Jacks for Uneven Pitches
A new problem arises in connection with uneven or irregular pitches, the problem of making the projecting cornice member one with another. Manifestly, if one part of a roof is steeper than another and the plate the same height all around the building, the cornice cannot be made to meet in the same plane. This difficulty is overcome by raising the plate of the steeper roof an amount equal to the difference in the rises of the two pitches for a run equal to that of the projecting cornice. For example, in a half-pitch the rise would be 24" for a run of 24" in the cornice. In a quarter-pitch rise for a 24" run of cornice would be 12", a difference in rises of 12". The plate of the steeper roof must be raised that much higher than that for the lower pitch.
Fig. 89. Deck Frame
48. Decks; Chimney Openings.—Decks are sometimes used in roof framing to prevent some part of the roof from rising too high above the remainder. Such decks are framed of joist stock spiked together with butt joints. Upon the top of such deck joists are placed feathering strips so sawed as to give the deck a slight "fall" in each direction, two to three inches in eight to ten feet. Upon these feathering strips flooring is laid.
The deck is framed, raised and braced, being held up by studding placed under each corner. Next, the hip rafters are placed, then the flooring on the deck, and finally the common and jack rafters. Should common rafters be placed before the deck flooring, the joists must be braced to withstand the pressure against their sides. On large decks the outer deck frame is doubled.
Chimney openings are framed as shown in [Fig. 89.]
CHAPTER V
Exterior Covering and Finish
49. Sheathing or Sheeting.—After the frame work of a building is erected and the openings made in the frame for windows and doors, the sheeting is to be placed. Sheeting is placed either horizontally across the studs or diagonally, sometimes both ways, depending upon the specifications of the architect. The diagonal is somewhat stronger but is more expensive. The horizontal is satisfactory upon ordinary frame dwellings, especially where the building is braced at the corners by studs cut in diagonally, or by sheeting placed diagonally at the corners as in [Fig. 90.] Such sheeting should be matched and well nailed with two 8d nails to each stud. Building paper should be placed upon the sheeting to further protect the interior from cold.