Using the thermal benefits of aircrete to build separating walls - by Cliff Fudge
When building new dwelling-houses and flats have you considered using aircrete blockwork for separating walls which can provide significant thermal benefits? Doing so can simplify your build process, save time, money and give improved thermal benefits.
Constructive Details Limited, a joint venture of the British Board of Agrément and Robust Details, has developed new handbooks of details to provide design values for linear thermal bridging. These new Constructive Details provide the construction industry with a simple range of technical solutions to optimise the design from heat loss through thermal bridging which need to be taken into account in Building Regulations Part L.
More specifically, H+H has worked with the Aircrete Products Association (APA) to launch a complete set of construction details for aircrete masonry with both partial and fully filled cavities. Using Robust Details means heat loss at junctions (thermal bridges) should be reduced by some 50%, providing significant cost savings in your build process. These savings are estimated as being in the region of £400 per house.
The issue of linear thermal bridging is hugely significant. As U-values get even lower, heat loss at junctions can now account for as much as 30% of the total heat lost through the fabric of a building.
Robust Detail constructions using H+H aircrete in separating walls will limit heat loss at wall junctions and other parts of the building. Wherever the separating wall breaks the continuity of the fabric insulation envelope – at junctions with external walls, floors and ceilings - thermal bridges exist.
If you use the DCLG’s Accredited Construction Details (ACDs) they assume that denser concrete blocks will be used. By using H+H Celcon Block Standard Grade in the separating walls the heat loss is significantly reduced.
It’s not only thermal benefits that you can reap by using H+H Celcon Blocks in your wall constructions. The passage of sound can also be reduced. You might not link light-weight with acoustic performance but the way aircrete blocks are formed, with their cellular ‘aero bar’ like structure, means they offer excellent sound insulation properties.
Using Robust Details offers an alternative to pre-completion sound testing (PCT) of separating walls and floors in newly built joined houses, bungalows and flats. This has been evidenced in recent times by Celcon Blocks’ inclusion in many Robust Details where new aircrete separating walls have been used to provide high credit ratings in the Code for Sustainable Homes (CfSH).