GB1495158A - Method of rendering artificial or natural structures moisture-proof - Google Patents

Abstract

1495158 Impregnating structures with water repellant BALFOUR BEATTY Ltd 31 Dec 1975 [31 Dec 1974] 56234/74 Heading D1P Part or all of a natural or artificial structure of stone, brick, timber, concrete or other building material in contact with the ground is waterproofed by applying suction to a surface of the structure to withdraw air or other fluid from pores and/or other voids within the structure and then, whilst continuing to apply suction allowing a water repellant material to flow through another surface into the structure at least to impregnate the boundary surfaces of the pores and/or voids and thereby form a substantially fluidimpermeable barrier. Preferably the process is used to form a damp - proof course. A transparent polythene sheet 15 is applied to part of one surface of brick wall 11, the edges of the sheet being sealed to the wall by putty or adhesive tape. A preformed duct 16 of transparent material overlys an opening in sheet 15 and allows vacuum to be applied. Preferably the wall is heated either by radiant heaters directed at the opposite side of the wall (Fig. 1a not shown) or by heating air drawn through inlet 21 of a polythene sheet 19 spaced from wall surface 14 by a layer of nylon mesh. The water repellent is then placed in channel 22 so that it is drawn through the wall 11' by the suction, suction is stopped when water repellent collects in duct 16. Channel 21 is formed by two strips of sheet 19 separated by spacers (25, Fig. 3 not shown). In another embodiment the water repellent is soaked in a strip (9, Fig. 1c not shown) of sponge and the strip is secured to the surface of the wall opposite to the vacuum source. The water repellent may be applied at a pressure of 50-60 lbs/ sq. in. a reciprocating. piston and cylinder connected to the pipe carrying the water repellent may be used to produce periodic pressurisation. Manual or mechanical, preferably ultrasonic vibration may be applied to the structure to shake out bubbles of air. Water repellent. The water repellent is preferably a silicone liquid. Where the structure is extremely porous hardenable low viscosity nolyester, epoxy or acrylic resins may be used Cracks may be filled in with the waterrepellent resin and the resin allowed to harden before water repellent material is sucked into the structure to coat the boundary surfaces of the pores.