Most houses are built of lumber, as it is not very expensive, is readily available, is strong and durable, and is easy to work. Ease of working is perhaps the most important property as far as the amateur build­er is concerned. A saw, a hammer, a hand axe, a square, a plane, and a few chisels will equip a per­son to make almost anything out of wood. Wood can be securely fastened by the simple process of driving a few nails; no other material is so easy to fasten. A little glue placed between two pieces of wood and pressed for a few hours will weld them securely to­gether. Steel requires elaborate welding or riveting, concrete requires reinforcing and intricate forms, brick requires considerable skill to get a passable job, but wood doesn't seem to care who works with it.

Wood is permanent and durable as long as it is kept dry. Wood frame houses two or three hundred years old are not uncommon. But if moisture gets into wood, decay starts and termites are attracted to it. Termites can be a real problem in the warmer southern parts of the United States, but proper care in framing can keep their threat to the minimum.

Wood that comes in contact with foundations, or with concrete, brick, or other surfaces that are in­clined to be damp, or wood that is exposed to the weather should be cedar, redwood, or cypress, or should be pressure-treated with chemicals.

In the western states the most commonly used framing lumber is Douglas fir. Pine, hemlock, spruce, tamarack, cedar, and white fir are also used in limited quantities. Do not use them for principal framing members. In the southern states long leaf yellow pine is used as a strong framing lumber. Each section of the country seems to have its favorites. Usually what the local lumber yard sells, if it also meets the de­mands of the building inspector, will be satisfactory. Quality of workmanship is of equal importance with the kind of material used.

Lumber contains many natural defects and ac­quires others in the process of milling and distribu­tion. The natural defects consist of knots, splits, wane, pitch seams, decay, cross grain, worm holes, etc., and the acquired ones may be under size, warp, twist, and most important, crookedness.

Small knots are not considered a defect in the construction grades, but large knots, especially near the center of joists or rafters, do weaken the piece materially. Although there is no need to worry about slight cracks or checks, a piece that is split too far should have the split part spiked well together or should be cut off and used for short pieces of some kind. A wane which is a place where the round part of the tree subtracts a small corner of the timber, is not usually serious. Discard any pieces that show signs of decay or contain too many worm holes. Crooked pieces can sometimes be straightened, es­pecially where two are used together, by placing them so the curvature of one tends to counteract the curvature of the other and spiking them together.

By selecting the better pieces for the most im­portant places, a really good frame can be built, con­taining many pieces that are not of themselves first class. Be sure to use plenty of nails, for the way build­ing frames are often nailed, less than a fourth of the actual strength of the timbers can be developed by the nails. The chapter on framing will give instruc­tions for nailing.

Although there are many grades of lumber, some of it graded for specific uses, the home builder will be interested primarily in the grades commonly used in house construction. The finish grades of Douglas fir are "B & Btr.," "C" and "D"; the framing grades are now construction grade, standard, utility, and econ­omy grades. Formerly such terms as No. 1 common, No. 2 common, etc., were used and are still used in some localities.

The construction and standard grades should be used for most of the framing and rafters, whereas the utility grade should be good enough for the studding, blocking, short span joists, etc. Select the best ones to place beside the doors and windows, and the straight ones for the corners. Many of the short pieces in the frame are mostly something to nail to, and do not need to be of the best. You can usually buy stud­ding already cut to length, 8' or 7'-ll" long, and 2" x A" in dimension.

The local lumber dealer will know what grades are required by the local building code, and what is ordinarily used in the vicinity. Do not try to economize too much in the quality of the lumber you use. Of course, a few small knots are expected in framing lumber; a large knot in the lower edge of a joist near the center of the span is much more serious than one near the end of the joist. Where two or three mem­bers are spiked together, a knot in one piece should do no harm. The members in the frame of a house are not actually stressed anywhere near to the break­ing point; joists and rafters which are required to be of certain sizes so they will not sag too much, are actually much stronger than they would otherwise need to be. See table, page 113, for recommended spans of joists and rafters.

Exterior walls are often made of stucco, brick, concrete blocks, aluminum, shakes, as well as wood siding.

Concrete is one of the most durable and strong building materials. The cost of the concrete is low, but the forms to hold it in shape are usually ex­pensive.

In places not subject to earthquakes walls of solid brick make an excellent building, permanent and of pleasing appearance, requiring little or no upkeep.

Stucco wire in place fastened with furring nails. Wire is 11/2 water table above boards where stucco begins. mesh, 17 gauge, galvanized stucco wire. Note