Thousand units 
3000 
2500 
2000 
1500 
1000 
500 
1960 1970 1980 
1990 
2000 2010 2020 2030 
Figure 3.2—New housing unit production in the United States, by type of unit, 1950-84, with projections to 2030 
more erratic. For example, the size of average new multi- 
family units in 1986 was about 911 square feet, 15 percent 
above the average in the early 1950’s, but down 10 per- 
cent from the mid-1970’s. Average floor area in new mo- 
bile homes, which more than doubled between 1950 and 
the mid-1970’s, has continued to rise because of the intro- 
duction of double-wide and expandable units. 
It has been assumed that rising incomes and consumer pref- 
erence for more space will lead to continued future growth 
in average size of all types of units. However, because of 
such factors as land costs and declines in household size 
mandated by changing demographics, such increases are ex- 
pected to be much slower than in the past. For example, the 
average floor area of single-family houses is projected to 
reach 2,000 square feet by 2030, an increase of less than 
0.25 percent per year. Growth between 1950 and 1986 
averaged about 1.4 percent a year. The size of units in 
multifamily structures is expected to rise to 1,100 square 
feet, about 75 square feet above the average in the mid- 
1970’s. 
In addition to the timber products consumed in the produc- 
tion of new housing units, substantial and growing 
volumes—about 20 percent of the lumber and structural 
panel products and 15 percent nonstructural panel products— 
are used each year for the upkeep and improvement of exist- 
ing units. Such growth is expected to continue in the 
future as the Nation’s inventory and average age of hous- 
ing units increase. 
New Nonresidential Construction—In recent years about 
10 percent of the lumber, plywood, and other structural and 
nonstructural panel products has been used in the construc- 
93 
