Let us take the case of an ordinary four-storeyed house (with no basement) having an area of 20 × 50 and 50 feet high. Then the curtilage would be (20 × 50 × 50) / 50 = 1,000; i.e., the house must have a curtilage exactly equal to the area occupied by the building—a back yard probably, 50 feet deep and 20 feet wide. If in addition to the four storeys there be a basement of 12,500 cubic feet, then an additional 250 square feet of curtilage would be required, and the builder who is tempted to overcrowd would be constantly checked by the price he has to pay for his obligatory curtilage.
The high price of building land is largely due to there being practically no restriction as to the cubic contents permissible on a certain area.
If we take the smaller two-storeyed cottages, having a width of 15 feet, a depth of 25, and a height of 20 feet, then the curtilage would be (15 × 25 × 20) / 50 = 150, which is the minimum of the 'model' by-laws. If the builder put a basement to this cottage of 3,750 cubic feet, he would have to provide additional 75 square feet of curtilage, and thus a check would be put upon underground dwellings and high buildings which obstruct the light and air. On the other hand, there need be no restrictions on the height or cubic contents of any building provided its curtilage be ample.
If it were possible for the first house considered to have a height of 100 feet in addition to its basement, then, the cubic contents being 112,500 feet, the curtilage would have to be 2,250 square feet, and the house and curtilage combined would occupy some 3,250 square feet, or rather less than 1⁄13 of an acre.
It is probable that a comprehensive rule of this kind would satisfactorily keep builder and site speculator in order, while it placed a minimum of restriction on the originality and fancy of architect and builder.
Builders of houses wholly detached from other houses or boundaries by a distance equal to the height of the house should be allowed to escape altogether from the harassing 'model' by-laws and the tyranny of the surveyor.
I would say finally—
1. That overcrowding is the greatest of all sanitary evils, and far and away the greatest of all moral evils.
2. That whatever increases the cost of the dwelling inevitably increases overcrowding.