Staining on brickwork is generally due to external causes but sometimes may result from salts in the bricks themselves.
Staining can mar the appearance of brickwork, but incorrect cleaning techniques can cause permanent damage, consequently, any proposed method of cleaning should be tried out in a small un-obstrusive area and left for as long as possible but at least a week or so, to judge the results, before the whole job is tackled.
(white crystals or white furry deposit)
This usually disappears rapidly from new brickwork due to the action of wind and rain but the process can be accelerated by repeated washings, allowing the wall to dry out at intervals. Brushing down the wall at times of maximum efflorescence will help to avoid removing the face. The salts brushed off should not be allowed to accumulate at the base of the wall, otherwise they may be carried back into the brick work by subsequent rain.
Where possible, remove large pieces with a scraper, then wash down with a dilute solution of hydrochloric acid (1 : 10 by volume).
Apply commercial paint remover or a solution of trisodium phosphate (1 part to 5 parts of water by mass), allow the paint to soften and remove with a scraper. Wash the wall with soapy water and finally rinse with clean water. In very bad cases it may be necessary to grind off the face of the brickwork in the affected area.
SURFACE DRESSINGS ON BRICKWORK
Varnish and brick dressings.
Varnish and brick dressings suffer from poor key and rapid deterioration due to sunlight and moisture movement. These finishes are difficult to remove from brickwork and so it is almost impossible to restore the wall to its original condition. As an indoor application however, this finish has been found to be reasonably durable.
Oiling of brickwork
If it is desired to brighten up brickwork, a mixture of clean engine oil and paraffin in the ratio 1:2 is recommended. This application gives a characteristic “oiled” appearance, without harmful side effects. The finish is not durable, but because it disappears through evaporation, can readily be re-applied without any further cleaning or pre-treatment of the brickwork being required.
- Where the proposed building requires more than one load of bricks, try to have them all on site before building operations commence. As loads differ slightly in colour, this will enable a proper mixing of the bricks to create an evenly mottled effect.
- When ordering, make sure of the quantities required. Reordering a small amount will create difficulties in matching the colours.
- It is recommended that a thick joint (plus-minus 15mm) be used, and the joint be recessed to allow the brick to display its natural beauty.
- Remember – the bricks will always appear less attractive in a stack. Their character only fully comes out once built in.