158 



THE OUTLOOK FOR TIMBER IN THE UNITED STATES 



Table 121. — Timber products consumed per housing unit, by type -J unit, 1962 and 1970, with projections 



(1970 relative prices) to 2000 1 





Lumber 



Plywood (%-inch basis) 



Building board 2 (^-inch basis) 



Year 



One- and 

 two-family 



Multi- 

 family 



Mobile 

 homes 



One- and 

 two-family 



Multi- 

 family 



Mobile 

 homes 



One- and 

 two-family 



Multi- 

 family 



Mobile 

 homes 



1962 . 



Board feet 

 11, 190 

 10, 840 



Board feet 

 4,500 

 3,700 



Board feet 

 1,510 

 1,680 



Square feet 

 3,010 

 5,385 



Square feet 

 1,800 

 1,910 



Square feet 

 1,840 

 1,300 



Square feet 



Square feet 



Square feet 



1970 



1,570 



125 



1,590 











Projections 











1980 



1990 



2000 



10, 660 

 10, 500 

 10, 260 



3,400 

 3, 100 

 2,900 



1,795 

 1,895 

 2,000 



6, 140 

 6,470 

 6,670 



1,950 

 1,975 

 1,985 



1,510 



1,620 

 1,720 



1,860 

 2, 100 

 2,310 



140 

 155 

 170 



1,625 

 1,680 

 1,775 



1 Includes both hardwoods and softwoods. Includes 

 allowance for on-site and manufacturing waste. 



2 Hardboard, insulation board, and particleboard. See 

 Append V, table 5, for projections of demand for these 

 products. 



bedrooms had increased to 11 percent and two 

 bedroom units to 47 percent of the total. 21 



Mobile homes have shown the largest increase 

 in average size. In 1962, only a fourth of the mobile 

 homes produced were more than 10 feet wide, 

 compared to over 90 percent in 1968. By 1970 an 

 estimated 8 percent of the mobile homes produced 

 were 14 feet wide and nearly 10 percent were 

 double-wide sectional units. The double-wides are 

 not only relatively large units but many utilize 

 heavier framing members and pitched roofs. 

 Lengths of mobile homes also increased sub- 

 stantially from typical lengths of 29 to 45 feet 

 in the early 1960's to units as long as 70 feet. 



For the future it was assumed that the rise in 

 family incomes and preferences of home buyers 

 will lead to further growth in average size of all 

 types of housing units produced. 



Structural and architectural characteristics. — 

 Along with growth in average size of units, the 

 percentage of new single-family houses built with 

 garages grew from 50 to 65 percent between 1950 

 and 1969. 22 Given the growing affluence assumed 

 in this study, the trend to more and larger garages 

 appears likely to continue. 



Other changes have led to the virtual dis- 

 appearance of porches that were once a feature of 

 nearly all one-family houses. Recently, however, 

 many houses have been built with wooden decks 

 which serve many of the purposes of the earlier 

 porches. 



21 U.S. Department of Commerce, Bureau of the Census. 

 Housing starts. C20-71-5. 1971. 



22 Characteristics of new one-family houses: 1970. op. 

 cit.; U.S. Department of Labor, Bureau of Labor Sta- 

 tistics. New housing and its materials, 1940-56. Bull. 

 1231. 1968. 



Average unit use of timber products, especially 

 lumber, has been reduced with the rapid growth 

 in proportions of housing units built with concrete 

 slab foundations. Between 1956 and 1970, the 

 proportion of single-family units constructed in 

 this way rose from 16 percent to 36 percent. 23 

 Construction of houses on slab foundations seems 

 likely to continue to grow, although at a slower 

 rate than in the past, in response to continued 

 population shifts to the South and Southwestern 

 sections of the Nation where slab construction 

 is used in a large proportion of single-family 

 houses. 



A new construction innovation that may offset 

 losses in timber products due to increased slab 

 construction is the all-weather wood foundation 

 system which uses substantial amounts of lumber 

 and plywood instead of concrete or block 

 construction. 



Another change that has significantly reduced 

 timber products use per unit has been the increased 

 importance of two-story houses. In 1956 less than 

 10 percent of the new, one-family houses had two 

 stories, in contrast to 17 percent a decade and a 

 half later. 24 This type of construction reduces 

 substantially the roof area and roofing materials 

 required to cover a given floor area. Two-story 

 construction permits enlarging house size without 

 increasing the size of the building lot, a factor 

 that should become increasingly important in the 

 future with rising land values. 



Rising land values have apparently also been an 

 important factor in the rapid growth in construc- 

 tion of townhouses or row houses in recent years. 

 Most of these units have common masonry side 



23 Ibid. 

 34 Ibid. 



