


THE AIR SEASONING OF WESTERN SOFTWOOD LUMBER 4] 
and grades of lowest value. Use of cheaper lumber is very important 
because of the high depreciation of roof boards. In actual checks of 
such depreciation, when No. 2 common-and-better pine stock was 
self-roofed, 70 per cent dropped at least one grade. If No. 3 or No. 4 
common were used to roof the better stock, a net saving of $2 could be 
made on each pile, over and above depreciation and extra handling of 
the special roof material. Although practice must, of course, be in 
accord with the local situation, since the price differential between 
grades varies with the species and climatic conditions also have a 
direct bearing upon the depreciation of roof boards, yet, as a general 
rule, the select and shop grades of all species, No. 1 and No. 2 common 
erades of pine, and if possible the upper common grades of other 
species, should be covered with special roof boards. This now con- 
stitutes the accepted practice in the majority of western yards. 
The essentials of proper roof construction are, (1) sufficient pitch 
to assure run-off, (2) suitable material and lapping to avoid leakage, 
(8) overhang at the front and rear of the pile, and (4) some clear- 
ance between the stock and the roof. Two general types of roof are 
commonly employed—that which provides a front and rear overhang 
and that which does not. The “overhang” type is constructed in 
two ways; with boards 2 to 4 feet longer than the piled stock or with 
double lengths of boards. The former method requires the use of 
special rood boards while the latter may be built with stock. The 
second type of roof, that which does not project beyond the ends of 
the pile, is constructed cf boards the same length as the stock and is 
most commonly used when stock is roofed with itself. 
Plate 7, B shows the common method of single-length stock roof 
construction. It consists of two layers of boards, the top course lap- 
ping the lower course of boards which are spaced several inches apart 
upon supporting stringers. These stringers, which bear upon the 
crossers and usually consist of crossers or stock laid one upon the 
others, form supports of different heights, the center lower than the 
front and the rear lower than the center. The double-length roof, 
as illustrated by Plate 8, A, is simply an adaptation of the former 
to give overhang at the front and rear of the pile. 
Adequate overhang of the roof at the front and particularly at the 
rear of the pile is very desirable. This gives some protection from 
rain and snow beating in at the ends of the pile, and by the shade 
afforded tends to avoid end checking in the stock on the upper 
courses. It also allows the drip from the roof to fall clear of the pile. 
The need for sufficient pitch to secure good run-off is obvious. The 
clearance between the roof and the stock is ordinarily sufficient for 
air circulation if adequate pitch is provided. Little difference in 
effect upon seasoning was indicated for roofs 1 inch, 6 inches, or 10 
inches high, although the rate of drying in the upper third of the 
pile may be slightly increased with the higher roof. The use of 
several crossers to hold the roof boards in place is usually satisfactory, 
but in windy situations or period of the year it is generally advisable 
to fasten rocfs to the piles with wire or roof irons. 
Although the tendency toward improvement in the style and work- 
manship of roof construction is very noticeable in the West, much 
can yet be done along this line. All stock should be roofed during 
air seasoning. Ordinarily, the use of stock roofs is justified only on 
the lower grades of common lumber. Adequate overhang, at least 
