It is of the greatest importance that dampness be excluded from the interiors of buildings, on account of its detrimental effect upon the health of the inhabitants.

Damp can enter a building in any of the following ways: (1) It may pass down through the tops of walls. (2) It may be caused by a driving rain passing through the surfaces of walls. (3) It may be forced through walls and floors of basements in water-logged soils. (4) It may soak up from the footings of walls in damp soil. (5) It may be forced through the lower floors by the movement of ground air. (6) It may pass through the walls and floors of buildings from faulty drains, gutters, or rain-water pipes.

1. Water is prevented from passing down through the tops of walls by fixing copings as already explained, and by the use of lead flashings as described hereafter.

2. Water is prevented from penetrating the surfaces of walls by any of the following methods.

Footings Copings Cornices Corbels Damp Proof Cours 337Footings Copings Cornices Corbels Damp Proof Cours 338Footings Copings Cornices Corbels Damp Proof Cours 339

Fig. 148.