Covered Cattle Yards. 
487 
tiles being made in the district. If they had to be brought from 
any material distance, carriage would add considerably to it. 
The wear and tear of a tile roof is also much greater than in the 
case of one of slate, and a larger sum must be allowed for this. 
On the whole, considering the difficulty there is in getting tiles 
sound and well burnt, the advantage they possess over slate, 
except in localities where manufactured, is not great. 
Open Slated Hoof. 
Reverting to the open slated roof, as shown in Fig. 3, the 
result of comparison of cost between it and the board roof is as 
below : — 
£ t. d. 
Open slated roof, first cost as per priced quantities . 81 15 2 
Interest, at 4 per cent, per annum, on S1Z. 15s. 2d., for 80 
years . . . 261 11 8 
Repairs, ^ per cent, per annum on first cost, for 15 years 6 2 6 
Repairs, lj per cent, per annum on first cost, for 10 years 40 17 0 
Total cost of open-slated roof for 80 years . . . 390 6 4 
Total cost of board roof for 80 years, as per foregoing 
statement . . , 438 12 7 
£48 6 3 
Thus, whilst the board roof costs less at the outset, the 
charges for renewals so burden it that, by the time it has reached 
eighty years, an ordinary form of roof covered with spaced open 
slating passes it in the economical race, and probably hence- 
forward will hold the field. For it must be remembered that at 
that date another board covering will be required, increasing 
the balance in favour of open slate to 73/. 7s. 2c?., approaching 
a sum which would very nearly renew the latter. 
Those who have followed me thus far will probably not differ 
much from the conclusions which the foregoing inquiry enables 
me to arrive at, provided they agree with the premisses on which 
they are founded. 
It is, as previously stated, a matter of uncertainty as to what 
age an ordinary corrugated iron roof and a f-inch board roof 
will attain. I have certainly dealt liberally with the former in 
basing calculation on an existence of forty years ; but, in taking 
the latter at twenty years, some may think I have given it scant 
justice. 
If an extension of five years' further existence were con- 
ceded, making the life of a board roof twenty-five instead ot 
twenty years, the situation at the end of the time to which my 
calculation extends would be materially modified, and the board 
roof would be shown to be the most economical of all, the open 
