SOME TIPS FOR INSTALLATION OF AAC

Joints and connections
The AAC manufacturer provides proprietary mortar mixes. Although more conventional thick-bed mortar (approximately 10mm) can be used with AAC, the manufacturer’s approved option is a proprietary thin-bed mortar. With this method, the procedure of laying the blocks is more like gluing than conventional brickwork construction. This is why many traditionally trained bricklayers may need some time to adjust to this different method of working.
In addition, brickies are used to lifting bricks with a single hand and AAC blocks often require two-handed manipulation. Although this may appear a slower construction process than laying masonry units, an AAC block is equivalent to five or six standard bricks.

Loadbearing walls
AAC is available in blocks of various sizes and in larger reinforced panels, sold as part of a complete building system that includes floor and roof panels, and interior and exterior walls.

Fixings
AAC has low compression strength. The use of mechanical fasteners is not recommended, as repeated loading of the fastener can result in local crushing of the AAC and loosening of the fastener. Proprietary fasteners are specifically designed to accommodate the nature of the material by spreading the forces created by any given load, whether it is a beam, shelf or picture hook. A number of proprietary fixings for AAC come with extensive guidance in product literature. If you are not sure, consult the project engineer or fastener manufacturer for guidance.

Carving and Cutting

AAC is soft enough to be cut with hand tools. Niches can be carved into thicker walls, corners can be chamfered or curved for visual effect and you can easily make channels for pipes and wires with an electric router.
Use appropriate dust reduction strategies with all carving and cutting, and wear appropriate personal protection equipment at all times.

AAC block and panels can accept cement render, but the manufacturer recommends using a proprietary render mix compatible with the AAC material substrate.
Site-mixed cement renders have to be compatible with the AAC substrate, with the render having a lower strength than conventional renders. All renders should be vaporized permeable (but water-resistant) to achieve a healthy breathable construction.

All external coating finishes should provide good UV resistance, be vaporized permeable and be proven suitable for AAC. Consult the manufacturer’s literature for further information on coatings.

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