Dry foundations are necessary in order to prevent moisture from rising by capillary at traction from the damp earth into the bases of walls or stoops. One or more perfectly water proof courses near the foundauons and reach ing above the level of the ground, should be introduced as a 'sine qua non' to a good build ing. Otherwise, a constant state of dampness, affecting that part of the structure, is apt to produce staining and disintegration beyond re demption. Cement or slate will not effectu ally this purpose owing to their ab sorbent qualities. Asphalt, sheet lead, copper or some other non-absorbent material should be used The modern practice of builders of valu able structures is to construct a waterproof "membranes completely enclosing the founda tion. This is commonly a succession of layers of burlaps cemented together with asphalt and united to the foundation material by the same impervious substance. An elastic felt recently introduced is claimed to be superior to the burlaps. Sheet lead as foundation waterproof ing is found in the ruins of Roman buildings 2,000 years old. One of the best processes hitherto employed for waterproofing the ex terior and interior surfaces of the walls, is the paraffine compound process. The base of this compound is paraffine wax of special manu facture with refined creosote oil and other sub stances not disclosed. The method of appli
cation is to warm the wall to be treated, to the depth of about one-quarter of an inch, thereby evaporating all moisture and rendering it absorbent of the waxy material. The melted waterproofing is then applied to the warm sur face until absorbed into the pores. It there re mains for a brief time in a liquid state, pene trating as deeply as the surface is heated and dry and gradually hardens as the surface cools. The pores are thus permanently tilled and ren dered solid without altering the appearance of the stone, etc., treated. This waterproofing compound thus forced in by heat and becom ing solid when cold, is far more durable and effective than superficial applications of cold solutions, oils or paints. applied in the usual manner, which do not penetrate into the ma terial, which soon perish, if they are not pre viously chipped or rubbed off.
As a preservative of stone and marble, of monuments and statuary, vaults. etc. from the destructive effects of the weather so often ob served in cemeteries, the process has proved of great value.
A material successfully used in Europe is a fluo-silicate of magnesia, commercially as 'fluate." Its application both hardens and rainproofs stone, but the effect is not instan taneous, as it takes a year to demonstrate it self. Consult Mierzinsld, S., 'The Water proofing of Fabrics.'