Please find below some tips for using bricks in external walls. Please feel free and use our tips to your advantage but in the event of being unsure of the appropriate details to use, please seek the advice of the prevailing standards required to build safely and satisfactorily.
TIP 1: Masonry and pointing mortar for brickwork
TIP 2: Using bricks in external walls
TIP 3: Guidelines for design and building
Tip 1: Masonry and pointing mortar for brickwork
Choosing masonry and pointing mortar should be harmonised with the properties of the type of brick you want to use. The level and type of detail of the cavity wall construction is also important. If in doubt seek the guidance of the Structural Engineer or Architect, responsibly for the project.
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Draft directive
In order to guarantee correct building - to reduce chances of Lime bloom, moisture penetration, Efflorescence, frost damage and cracking - and for durable performance of brick outer leaves, the designer should allow for an air cavity of at least 40 mm clear air space between the insulation and outer wall leaves.
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Masonry mortar recommendations
For composition of masonry mortar under normal conditions of exposure we recommend using a 1:1:6 (cement:lime:sand) mix. In areas of high exposure and with very hard, dense bricks then a 1:1/4:3 (cement:lime:sand) mix should be used but with the richer cement mixes, consideration must be given to the possible shrinkage of the joint which may lead to hairline cracking of the brick mortar.
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Premix Mortars.
Ready Mixed, Premixed mortars, with drying retarders are readily available to the Construction Industry but it is advisable to seek the individual manufacturers instructions on their use and availability.
The moisture content and water absorption of the bricks at the time of building is also important. The premix mortar supplier can provide more information about this. Generally, it comes down to acclimatising the brick on site by delivering them two days before they are required so that they are wind dried so that they (wet on the inside and dry on the outside) achieve the required bond strength between brick and mortar more satisfactorily than if they are saturated.
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Pointing mortar recommendations
Depending on the required hardness of the joints, the joint surface should be struck/compacted after the joints are filled with a softer wash sand. In some circumstances a silver sand is preferred. The quality of the joints can be determined afterwards with a joint hardness indicator.
Where coloured mixes are preferred, a ready-mixed coloured mortar should be used, giving a better chance of maintaining colour consistency. Shovel gauging should not be used. They should not be trowelled excessively, as this can affect the colour achieved. Ensure that all joints are fully filled with mortar. Frogs (indentations in the brick) should be face upwards and frogs and perforations should be fully filled.
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How to use guidelines
Refer to our leaflet "Designing and using bricks in external walls" for brickwork.
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Tip 2: Using bricks in external walls
Basic rules for masonry bricks, masonry and pointing mortar, bricklaying and jointing which should be used are briefly summarised in the PDF document shown below.
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Tip 3: Guidelines for design and use
This document contains an elaborate description of aspects that should be considered for designing and processing brick masonry.
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Please open the PDF document: Guidelines for design and use (PDF)
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