DEMAND FOR TIMBER PRODUCTS 



157 



New housing unit production by type of unit, 

 1920-72, with projections (medium level) 

 to 2000 



1920 1930 1940 1950 1960 1970 1980 1990 2000 



Figure 62 



Demand for New Housing by Type of Unit 



Because of large differences in quantities of 

 timber products used per unit, type of housing 

 units demanded is of major importance in 

 projecting demands for timber products. 



In the 1920-72 period 1- and 2-family units were 

 the dominant types of new units produced (table 

 120, fig. 62). There has, however, been a substantial 

 amount of variation in the relative importance of 

 these units. During the 1920's, proportions of 1- 

 and 2-family units reached a low of about 73 

 percent of all new units produced. By the mid- 

 1950's such units accounted for over 90 percent 

 of all new units. In the late 1950's the trend 

 changed again and by 1972 1- and 2-family units 

 accounted for only 47 percent of total housing 

 production. 



From the 1920's through most of the 1950's 

 multifamilv units accounted for the remaining 

 housing output but by the late 1950's the mobile 

 home had emerged as' a significant source of new 

 housing. In 1972 mobiles composed over 19 percent 

 of total new housing production. 



Single-family housing units have typically been 

 occupied by middle age classes, a response to 

 family size and income. Occupancy of multi- 

 family units and mobile homes, on the other 

 hand^ has been highest among the younger age 

 classes, which typically have small families and 

 relatively lower incomes and among older age 

 classes. 



In this study, occupancy rates by age class and 

 type of unit prevailing in the late 1960's were 

 assumed to continue through the projection 

 period. Prospective shifts in age distribution of 

 the population indicated earlier in this section 



result in substantial changes in projected demands 

 for the various types of units (table 120, fig. 62). 



Projected demand for 1- and 2-family units 

 continues to increase in the 1970-2000 period and 

 constitutes the major element of housing demand. 

 Projected demand for multifamilv units is relatively 

 high in the 1970's, because of the large number 

 of young households, but drops in the 1980's and 

 early 1990's. 



Projected demand for mobile units used as 

 primary residences remains relatively constant 

 during the projection period. Additional produc- 

 tion of mobile homes is expected for part-time 

 use as vacation homes, offices, and other non- 

 dwelling purposes. An estimated 20 percent of all 

 mobile units produced in 1970 was used in this 

 way and this percentage is assumed to continue. 

 Projected total demand for mobile homes thus 

 averages about 500,000 units a year (medium 

 level) . 



Conversions 



Conversions of existing housing units into 

 two or more units, and conversion of nonresidential 

 structures to housing units, has at times met a 

 substantial part of the Nation's housing demands. 

 In the 1930's, for example, more than one-third 

 of all units provided came from such conver- 

 sions. Projected housing replacement demands 

 include an allowance of 100,000 net conversions 

 per year — about the same number as in the late 

 1960's (table 118). 



Timber Products Use Per Dwelling Unit 



Since the beginning of the 1960's there have 

 been significant changes in average unit use of 

 timber products in housing (table 121). Use of 

 plywood and building boards, per unit, has risen 

 substantially, while use of lumber has declined. 

 These trends reflect factors such as changes in 

 unit size, structural and architectural charac- 

 teristics, and materials substitution. 



Trends in unit size.— In the 1960's there was a 

 fairly steady increase in size of single-family 

 units constructed, with the average rising from 

 1,340 square feet in 1962 to 1,500 square feet 

 in 1970. 20 This growth in size of units contributed 

 to the rise in use of plywood per single-family 

 unit and partially offset a downward trend in lum- 

 ber use per square foot of floor area. 



There also has been an increase in the average 

 size of multifamily units. In 1965— the first year 

 such data became available— 5 percent of the new 

 units in privately owned apartment buildings had 

 three or more bedrooms, 44 percent had two bed- 

 rooms, and the remainder were one bedroom or 

 efficiency units. By 1970, units with three or more 



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

 Characteristics of new one-family homes: 1970. CJ5-/U-10. 

 1971. 



