Walls tarred, painted, or treated with any of the water-proofing liquids now on the market offer considerable resistance to the penetration of moisture.

A more lasting method is to rake out the joints and render the whole face of the brickwork in cement mortar, composed of Portland cement and sand in equal proportions. Asphalt may be applied in exactly the same way.

Walls faced with non-absorbent bricks, such as Staffordshire blue bricks, or of stone such as flints split to form fairly flat faces, and set in cement, are very impervious to moisture. Glazed bricks and tiles also form good veneers for the exclusion of damp, and by judicious use of the various colours and designs in which they are now manufactured very fine effects may be produced.

A method of forming damp-proof walls, now much employed in the suburbs of London and in the southern counties generally, is to face walls with tiles hung vertically on battens, as shown in the Chapter on tiling in Volume II. of this work; while in some districts, notably in Hampshire, slates are used in the same manner.