Flashings and Valleys
There are a few important things to remember when talking about flashing. The raised piece at T is a wooden fillet nailed on; it is about 1 k in. high, and about 1 in. broad, over which the lead is turned, as per dotted line, Fig. 66. Where flashings are put on up against a brick wall or chimney, a different style has to be adopted from that hitherto described, as no grooves are cut in the brick the same as in stone. Chapter V. shows how the raglet is cut up the side of a stone chimney, but instead of the straight line there shown, in brickwork the joints of the bricks serve for the chasing, which shows part of a chimney built in brick.
The other lines show how the lead steps are put in, the dots showing position of their overlaps. To hold the apron into the joints of the bricks, lead bats can be used in some good brickwork. In other cases some use wooden wedges, and others, again, use " thumbats," or iron holdfasts, about 3 in. long, and with thin flat heads, as per Fig. 69. After the aprons have been fixed, the joints require to be cemented, or filled up with mastic.
Instead of putting on the flashings as described in Figs. 67 and 68, some use "soaker" or put on the flashing in pieces to suit the bricks and slates, one half of each piece of lead going up against the bricks, and the other half underneath the slates.
In Fig. 67 the horizontal length of each lead step will be about 1 ft. (in other cases it may be either more or less), while the breadth at the lower end will be, say, 7 in., and at the higher end, say, 3 in.; 7 in. + 3 in. = 10 in., gives 5 in. as the medium breadth of each step, which 5 in. being multiplied by 1 ft, the product is the measurement of each single step. If the sum total is wanted, then, supposing there are ten steps, 5 in. x 1 ft. X 10 = 4 ft 2 in.
The valleys, or " flanks," as they are sometimes termed, are the inclined channels formed by two roofs meeting, say, at right angles; the breadth of either lead or zinc used is from 1 ft. upwards. " Doubling," or wooden fillet is put on all up each side of these "flanks," especially if lead is used, as per Fig. 70. If zinc be used, however, the wooden fillet is often dispensed with, a small roll being turned in on each side of the zinc for the slates to rest on.