54 The Colorado Experiment Station. 
with top and bottom bolts rather than to a cross bar. Chains or 
straps and staples and pins should be provided to hold doors safely 
when they are to be left ajar; and some provision should be made 
to hold all doors securely open or shut to protect them from damage 
by wind and wagons. 
The Roof is best made of dirt and straw, not alone for cheap¬ 
ness but because of their superiority as insulating material. In a 
rainy country a tight roof over the dirt might be required, although 
our dirt-roof cellars when in good shape leak only during pro¬ 
longed and heavy storms. Even where concrete construction is used 
for the walls, it seems wise, as yet, to 'make a temporary roof, and 
to expect to renew it once in ten or fifteen years.f 
Framing the Roof. —Rafters should be sound poles 4 inches at 
small end, set 15 inch centers, or 2 x 12 sawed stuff. Purlines 
should be built up of two or three 12-inch planks. Posts should be 
not more than 10 feet between centers at the most and should be at 
least 8 inches at upper end. Two rows are sufficient in a 36 foot 
room, but four lines of posts are required in a wider cellar. 
Good Foundation for the posts and walls is required. The 
roof is extra heavy at times of rain when the foundation soil is 
liable to be soaked. Gravel or cobble stone bottom is firm but clay 
subsoils are often semi liquid when soaked, and on such foundation 
the largest flagstones are required beneath the posts and side walls. 
Cost of the Experiment Station Cellar.% —Gravel, 61 loads, 
$76.50; poles, $73.15; lumber, cement and paint, $315.30; hard¬ 
ware, $59.85, including square rods for reinforcing; sash, $7.40; 
contract work for erecting forms, mixing and putting in concrete 
at $3.25 per cubic yard, $191.00; working foreman at $4 per day 
and railroad fare from his home, $87.20; straw, $6; labor, $332.85.* * 
Total: $1,149.25. See Plates XIV, XV, XVI, XVIII. 
Farm Costs of a Similar Cellar .f—The cash expenditure on a 
farm for such a cellar will be reduced from the above by omitting 
charges for horse labor, by the use of efficient farm help, by the sub¬ 
stitution of old digger chains for boughten reinforcement, and in 
fReinforced concrete over dirt and straw would make a permanent 
job, but is in the experimental stage, and is too expensive for trial by in¬ 
dividuals. 
tThe potato specialist built the cellar rather than let a contract, so 
he could keep an account of costs. For administrative reasons, the con¬ 
struction was delayed into potato harvest, and he was compelled to hire 
a competent foreman. 
*This includes carpenters and painters at union rates, and team work 
at $4 per day. 
tThe best farmers reckon cost of teams as well as of wear and tear 
on wagon and tools, cost of board and value of their own time, in cal¬ 
culating such a job. 
