How to seal cracks in brickwork

Cracks in Brickwork!

Cracks in brickwork provide an easy route for water to penetrate into masonry walls during periods of wind-driven rainfall.  In cold weather water confined within these openings freezes, expanding in volume as it changes into ice.  This expansion process exerts a great deal of pressure within the brick and causes hairline fractures to widen, allowing more water in..

Unless fissures and crevices are sealed with an effective filler the freeze-thaw cycle continues and the bricks become progressively more damaged.

How to Fill Cracked Brickwork

Filling cracks in mortar joints is usually a fairly simple process whereby the cracks are mechanically widened to permit sufficiently-deep repointing of the wall with new mortars.  However, hairline cracks in the bricks are not so easily filled to an adequate depth.  They require the use of purpose made injection systems to ensure that cracks are sufficiently filled and adequately sealed.

There are various brick-filling adhesives available that have been designed to fill hairline cracks in brick, block, stone and concrete walls.  With all such products, cracks are first prepared by using an air-line or vacuum to remove loose or friable particles. The substrate needs be free from dust, dirt and other conta­mina­tions to permit a long-lasting repair.

Injection mortars are mixed in accordance with the manufactures instructions.

They are transferred to a caulking cartridge fitted with a nozzle suitable for the width of crack in the wall.  With the correct injecting-nozzle, it is possible to inject proprietary resins into cracks that are as narrow as 1mm wide.

Crack sealing material is injected, as deep into the cracks as is possible, using an injection nozzle that is complimentary to the width of the fissure, filling the opening from its base to the surface. Operators should note that chemical reactions occur when mixing adhesives and the heat they generate tends to limit workability, giving a relatively short time in which to apply the product.­  Accordingly operators are advised to prepare everything beforehand so that the injection process can take place without interruption.

The use of tinting agents or brick dust, applied whilst the sealer is still tacky, improves colour match with the substrate.

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