Aircrete cavity walls: the simplest move to better performing homes

Up to 35% of a building’s heat is lost through walls and another 35% potentially lost through thermal bridging, Mannok Aircrete blocks provide a solution...

Mannok Aircrete blocks are widely regarded as the best solution to tackling heat loss through thermal bridging as they can reduce heat loss by up to 80% compared to dense concrete blocks. Aircrete blocks are commonplace on building sites across the country, most often used in the floor to wall junction to ensure continuity of insulation at this location. This addresses one junction, but if you’re serious about tackling thermal bridging, it is necessary to apply the same solution to all junctions to reduce heat loss. This can result in a patchwork effect of different block types when mixing Aircrete and dense concrete blocks in the wall.

The much more straightforward solution is to simply build the entire inner leaf of the cavity wall with Aircrete blocks. This one switch addresses all thermal bridges almost by default, ensuring up to 80% less heat loss through cold bridges, and improves the wall’s overall thermal performance by improving the U-value. In addition, it makes life much easier for the builder – there’s no mixing different types of blocks, no switching from one to another at different locations and reduces the risk of errors as a result. Plus, there’s no differential movement, which can occur when mixing the block types.

Perhaps most important for the homeowner or buyer is the prospect of a more comfortable, energy efficient home with reduced heating bills. Aircrete cavity walls not only insulate the home much better than standard cavity walls, but the blocks also have a faster heating response time. Thanks to their lightweight properties, Aircrete blocks don’t absorb as much heat as heavier blocks from the room, so when the heating is switched on, the home will heat up much quicker, with one study showing that lightweight construction methods can heat a room up to six times faster.

The cost difference will vary by property, but is generally a very small percentage of the overall build, which is offset quickly by the resulting energy savings, and well worth it for the added performance benefits. Looking at a 2,000sq.ft. bungalow as an example, the cost to move from using Aircrete blocks to tackle thermal bridging in all junctions, to building the entire inner leaf with Aircrete blocks, will only cost around £500 extra in NI. In many cases, the net result can in fact be cost neutral with the support of the Mannok Technical team to advise on specification and provide relevant calculations, making it an appealing option for self-builders and developers alike.

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