ing knots, and sharp edges. Do not use green lumber; the sun
is almost certain to shrink and warp it. Sometimes it will even break the
roofing material. On very particular work, where the rafters are wide
apart, the best builders recommend laying a course of boards over the
planking at right angles to it.

Valleys

If there are valleys in the roof (Fig. 298) use a long strip of roofing
and lay it up and down in the direction of the valleys. Press the strip
into the hollow so that it takes the shape of the valley itself. Allow the
edges of the roofing to overlap the strip in the valley an equal distance
on both sides of the valley (Fig. 298).

How to Lay the Roofing

Begin at the eaves to lay the roofing (Fig. 299). Always lay the roll of
patent roofing with the inside surface to the weather and in the same
direction that the boards run--not at right angles to them. Begin nailing
at the centre of the edges of the strips and work both ways to the
ends--never the reverse, as the roofing may become wrinkled, twisted, or
crooked. Always set caps even with the edge of the laps about two inches
apart between their centres.

Gutters

To finish gutters, fasten and carefully cement with the pitch or tar or
prepared composition the edge of the strip about half-way to the gutter.
Bring the other edge onto the roof, then lay the next strip over this
strip so that it will overlap at least two inches. Proceed to lay the
balance of the roofing in the same way. Never nail the middle of the
strips; nail only along the edges. The end strips should always be lapped
over the edges of the roof and fastened (Figs. 297 and 299).

Before fastening laps paint a two-inch strip with the tar or pitch cement
which comes with all patent roofing in order to stick it to the lower
strip of roofing and to make a tight joint when put in place.

Do not drive nails carelessly or with too much force and be sure the cap
fits snugly against the roofing. If nails go into holes or open cracks, do
not remove them but thoroughly cement around them. Allow six inches for
overlaps for joints where one strip joins another (Fig. 299, _B_). Be sure
that two strips of roofing never meet at the ridge leaving a joint to
invite a leak over the ridge-pole. Examine the diagrams if you fail to
understand the description.

How to Patch a Shingle Roof

The reader must not suppose that the roof of my camp was made of flannel
because it shrank, for the whole ho