p* I USE or r E FOR HOUSE CONSTRUCT I By P. F. LUXFORD, Engineer Forest Products Laborato ry.- Forest Service U. S. Depart.nent of Agriculture Introduction of the principal uses of Engelmann spruce is for construction purposes. It is grouned with such woods as nonderos 3 pine, northern white Dine, su pine, western redcedar, basswood, and balsam fir. Thr- properties desired in building material may bo divided into two groum — one containing those properties that tend to insure satisfactory service when the wood is in place, the other containing those properties that tend to facilitate construction and thus reduce cost. Strength, stiffness, nail- holdinr power, and stability are important properties in the first group. Light weight, softness, and ease of workinr are those of the second group. oannot excel in the properties of both groups, since, for instance if it has high strength, it is comparatively heavy and hard. Engelmann sprice would be c] assed with the species that are light in weight and are easy to work, while such woods as Douglas-fir and southern yellow pine excel in strength and stiffness . -jlmann spruce ranks relatively h in freedom from warpin ' and in raint-holding ability. It is classified as a low-shrinkage wood and at identical moisture content behaves about the same as ponderosa pine. Its resistance to decay is relatively low, and It has a relatively small amount of heart-wood. The wood oi' Enge In- spruce is generally straight-grained and can be readily air dried. In t-holding properties &ngelmann spruce is classed with ponderosa pine and western hemlock — below the white pines, cedars, redwood, and cypress, and above ' ou -las-fir and southern yellow pine. Uses in House Construction i V.'hile E ngelmann spruce can be used for many parts of a house, it is probiV i used most extensively in the form of dimension and corrnon boards. ~.aintained at Madison, '.Vis., in cooperation with the University of Wisconsin. Rert. Mo, R1944-1 - Agriculture-Edison Exterior Trim The usual requirements for exterior trim are medium decay resistance, good painting and weathering characteristics, easy working qualities, and maxi- mum freedom from warp. Engelmann spruce would rate along with hemlocks, ponderosa pine, and white fir for exterior trim. It would not be the equal of such woods as cedars, cypress, and redwood. Framing Framing should be high in stiffness, have good bending strength, good nail- holding power, hardness, and freedom from pronounced warp. For this use, dryness and size are sometimes more important factors than the inherent properties of the different woods, Engelmann spruce is relatively low in strength properties, but this deficiency in strength can, of course, be compensated for by using somewhat larger sizes. This is particularly true for such purposes as floor joists and roof rafters. The sizes of some ileitis such as studding are largely fixed by common practice. American Lumber Standards sizes were established with a view to having the sizes adequate for the lighter weight and weaker species. Engelmann spruce could, therefore, be used in the same stud size as the heavier and stronger species. Any nailing deficiency could be compensated for by use of larger or more nails Engelmann spruce would be gouped with such woods as northern white pine, sugar pine, and ponderosa pino. Ip^ srior Trim with Paint F inish Material for interior trim should have a fine and uniform texture, hard- ness, absence of discoloring pitch, and freedom from warp and shrinkage. For this purpose, Engelmann spruce would be classed with such woods as redwood, the hemlocks, and white fir. It would not be the equal of the commercial white pines and birch, walnut, and yellow-poplar. The hardwoods are, of course, considerably more resistant to denting, and where this property is of importance, Engelmann spruce would not prove satisfactory. Ro of Boards Roof boards should have high stiffness, good nail-holding ability, small tendency to warp, and be easy to work. Roof boards, however, are one of the less exacting items in house construction and Engelmann spruce could often be used in lieu of the stronger and harder woods, such as the hem- locks, eastern spruces, and white fir. It might require somewhat more nailing to hold shingles than if the harder and denser species were used. Siding Siding should have good painting characteristics, easy working qualities, and freedom from warp. Woods excelling for use as siding include cedars, cypress, the commercial white pines, and redwood, Engelmann spruce would Rept. Mo. R.1944-1 -2- rank with ponderosa pine and western hemlocks for use as siding. It would somewhat superior to «uch woods as Douglas-fir, western larch, and southern yellow pine. Wall Sheathing Wall sheathing is not a very exacting use, although easy working, easv nailing, and moderate shrinkage are desirable properties. Many woods can be used for sheathing with satisfactory results, although some woods are leea time-consuming to work than are others, Engelmann spruce would be rated along with the vhite firs, commercial nines, and hemlocks. Engelmann spruce slieathing contains sinaller but more numerous knots, is lighter and can bo sawed and nailed more easily than such woods as Douglas-fir and soutliern yelloxj pine. rith Natural or High-cl a ss Paint Finish Requirements for shelving include stiffness, good finishing qualities, and freedom from pitch and war]). Many woods are suitable for this use and almann spruce would be included along with the commercial white pines and would bo somewhat superior to Douglas-fir, hemlocks, western larch, and soutliern yellow pine. Subfloorlng The requirements for subflooring are not exacting, but high stiffness, medium shrinkage and warp, and ease of working ai-e desirable characteris- tics. Many woods aro used for this purpose with satisfactory results, Engelmann spruce would be classed along with the commercial white pines, henlockSj ponderosa pine, and white fir. Conclusions While Engelmann spruce can be used for many construction purposes, the greatest outlet will probably be for such U3es as studding, subflooring, roof boards, and wall sheathing. Rept. No. R19U-1 -3- June 1952 UNIVERSITY OF FLORIDA 3 1262 08924 0989