Cleaning new face brickwork
Mortar smears and deposits should be cleaned by hand with a hard scrubbing brush using water and possibly a commercial mortar cleaner as work progresses.
- For light coloured bricks which are likely to contain vanadium salts, do not use hydrochloric or muriatic acid for cleaning as they will fix the salts, make them insoluble and difficult to clean.
- Do early trials to ensure chemical compatibility with materials being used. Ensure that all proper safety precautions are taken when using chemicals. When diluting concentrated acid, always pour acid into water and never vice-versa.
- Identify the nature of masonry to be cleaned and the type of stain to be removed before deciding on the cleaning method. Try method on a small area of wall. Protect metalwork, building materials and plants from chemical liquids, sprays and fumes.
- Do not clean brickwork exposed to hot sunlight
- Do not use wire brushes or other abrasives on brick faces.
LIME BLOOM STAINING
Lime bloom staining originates from common cement in mortar and concrete structures. It is released into solution in the early life of a wall and dries out on the surface of the brick as an insoluable salt that is difficult and expensive to remove. You must prevent saturation in the first 24 hours and then protect form rain for the next week.
Incorrect cleaning can cause worse stains than natural dirt. As cleaning techniques differ for different types of masonry and stain, identify the kind of brick and the nature of the stain before commencing any cleaning. Get recommendations from your local brick supplier.
Thoroughly saturate brickwork before and wash after applicaiton of chemicals.
When using chemicals such as acid based solvents for removing mortar, allow the cemical to react for 5-10 minutes, then wash down thoroughly with clean water.
When the stain is localised, most cleaning liquids can be applied as a poultice by thickening with talc or powdered chalk.
Efflorescence is caused by salts present in the brick, sand or cement. These are deposited on the surface of the brick in a dry, crystallised form.
The best cure is prevention. Good detailing that minimises the ingress of water into the brickwork is the most important step to minimise efflorescence. Protect bricks from ground water, and stack bricks separately from other materials.
After the fact, our recommendation is to allow the efflorescence to form and dry out over 4-6 months. Brush off dry, or wash of with water using a hard bristle brush. If unsuccessful, refer to a cleaning specialist. Do NOT use hydrochloric acid.
Application of ammonium sulphate or weed killer, in accordance with directions results in removal or moss or unwanted plant growth.