Clay bricks

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Posted on November 21, 2013

Clay bricks are made from natural products meaning from batch to batch and within each batch there are natural colour variations which can occur. Bricks are kiln fired at very high temperatures to lock in their colour and strength. It is important when bricks arrive at site that the bricks are blended to distribute the natural variations across the entire wall. This is an important step whether the products you have delivered are a single colour or are multi-coloured.

Blending instructions are on the side of most packs. The most common instructions include:
1. Work from at least three open packs.
2. Select the top brick or paver from the left of each pack.
3. Work progressively from a corner across and down each pack in a diagonal pattern. Do not unpack the bricks or pavers in horizontal layers.
Be sure to inspect the product before laying. Product liability transfers to the purchaser once the units are installed.
The appearance of brickwork can be spoilt by bad cleaning techniques or by the use of the wrong cleaning agent. For this reason, it is important to ensure that the correct cleaning methods are utilised. A comprehensive document outlining the key considerations when cleaning bricks is available by following this link:
http://www.thinkbrick.com.au/assets/documents/technical_information/brickwork/TBR4978Cleaning-Masonry2HR1.pdf

Please find below a summary of the Think Brick document as well as other useful hints and tips:

· The more care the bricklayer takes in keeping the work clean, the easier the final clean up will be. The brick layer should clean mortar residue and smears as the job proceeds.

· Large hardened mortar particles need to be removed with a hand tool before any water or cleaning solution is applied.

· Traditionally bricks are cleaned with an acid solution. There are specific acid to water ratios the cleaner must follow to avoid stains appearing after the job is completed. Under no circumstances should more than 1 part hydrochloric acid to 10 parts water be used. It is better to scrub more vigorously than to use more acid. Acid solutions that are too strong are a problem.

Protect all areas which may come in contact with the cleaning agent -. special care should be taken with window frames, aluminium dampcourses and gutters.
Only clean small areas at a time, for example one square metre, so as to allow adequate time to wash off the cleaning solution, to ensure no staining occurs.
Always begin at the highest point and work down the wall.
· Walls must be completely saturated before acid is applied and then thoroughly rinsed off before the acid is absorbed into the brickwork.

· Hand cleaning of walls was widely used before the introduction of high pressure water jets and is still used now for smaller jobs or where such high pressure may cause other problems.

· Applying acid solutions under high pressure is not recommended. Acid should be applied using a masonry cleaning brush, soft broom or low pressure (max 40psi) spray.

· When washing the walls of the acid, a high pressure jet can be used but kept low at 1000-1200psi to prevent damage to both the masonry and mortar.

Ensure that the brickwork is sufficiently rinsed after cleaning.
Note:
1. Light coloured bricks should be rinsed with a neutralising solution, such as bicarbonate of soda or washing soda, instead of water.

2. Bricks manufactured in Queensland, especially light-coloured bricks, may be more susceptible to acid burn, due to large amounts of iron oxide present in the raw materials.

3. Dry press, slurry coated or glazed bricks should be cleaned by hand, or by low pressure water jets.