18j~ BULLETIN 246, U. S. DEPARTMENT OF AGRICULTURE. 
a cents. These figures mean very little, unless the kiln is located con- 
veniently near where the brick are to be used, for freight charges not 
infrequently amount to more than the cost of the brick. 
A force consisting of one paver and five laborers should place on an 
average about 220 square yards of brick per 10-hour day; while 
supervision, rolling, and incidental expenses are ordinarily equivalent 
to the cost of hiring about three and one-half additional laborers. 
If C = cost of cement per barrel, S = cost of sand per cubic yard, 
A = cost of coarse aggregate per cubic yard, B = cost of paving j 
bricks per 1,000, and L = cost of labor per hour, with all materials 
considered delivered on the work and all costs expressed in cents, then 
the probable cost of constructing a brick pavement, including the 
subgrade, a 6-inch concrete foundation, and suitable curbs, may be 
estimated by substituting in the formula : 
Cost per square yard = 1.90 L + .213 C + .138 S + .157 A + .040 B. 
The cost as estimated from this formula should usually be in- 
creased by about 10 per cent to allow for wear on tools and machin- 
ery and to guard against unforeseen contingencies. If it is desired 
to use a different thickness of foundation, it is safe to assume that 
each inch subtracted or added to the thickness of the foundation will 
make a corresponding difference of from 8 to 12 cents in the cost per 
square yard. 
MAINTENANCE OF BRICK PAVEMENTS. 
If brick pavements are properly constructed at the start, the work 
of maintaining them is very slight. Under the closest inspection, 
however, some inferior material is likely to become incorporated 
either in the foundation or in the surface, and it is therefore very 
important that a brick pavement be very carefully watched for the 
first few years of its life to see that no unevenness develops either 
because of defective brick having been used in the surface or because 
of insufficient support from the foundation at any point. Whenever 
any unevenness develops, it should be immediately rectified. Other- 
wise the pavement will become irregularly worn in the vicinity of the 
defects, and expensive repairs will eventually be necessary. 
Xot infrequently weak spots develop in broken stone or gravel 
foundations, owing to surface water finding its way through joints 
in the pavement which have not been properly filled with grout. 
Careful observation of the joints should therefore constitute a part 
of the early maintenance work, and any defective joints discovered 
should be immediately remedied. 'Where the foundation is con- 
structed of concrete, however, slight defects in the joints seldom 
result in any very serious damage. 
