Zero Carbon standards from a 100mm cavity...New BBA approved insulation system achieving 0.16 U-value in a traditional wall

With the revision of Building Regulations Part L, the Government wants to bite off a sizeable chunk of the Zero Carbon target that has been set for 2016. The new 2010 Part L changes that come into effect in October, will see an objective to construct homes to a standard 25% improved on the 2006 position, one more significant step towards the Zero Carbon goal.

Delivering these new standards on site will be a challenge for all those involved in the building industry, remember, this is just ‘the next step’, this change will be followed quite quickly with a further set of improvements in the next 2-5 years.

Is there an end in sight? a target to which you can aim your specifications? Well perhaps at least for the building fabric performance there is - clarity is now being offered in the form of the Fabric Energy Efficiency Standard recently announced by Government, and formulated by the Zero Carbon Hub.

They have indicated the U-values, air tightness and detailing that will define a Zero Carbon Fabric – and it’s not that far from what is required of you from October. Take wall U-values for example, it is likely that a U-value of around 0.22 W/m2K will be required to achieve Part L without renewables – Zero Carbon has been indicated at around 0.18W/m2K.

So how do we push the thermal performance of traditional walls towards Zero Carbon standards, - take the obvious solution of simply widening the cavity and adding more insulation: you may indeed succeed in achieving a very good U-value by increasing the insulation thickness however you are either reducing floor area or increasing the dwelling footprint. There are cost implications too. To increase a cavity out to 200mm on a semi-detached property will necessitate changes to founds, sills, roof etc and could add up to £28.25 per square metre of external wall area - before insulation costs are considered. (A cost report from Cyrill Sweett is available from Xtratherm)

The technology now exists to meet and exceed the 2010 standards within a traditional wall specification. CavityTherm, developed by Xtratherm, is the new BBA approved built in full fill wall insulation system designed to work within the traditional 100mm cavity and meet the Fabric Energy Efficiency Standards for Zero Carbon Homes achieving U-values as low as 0.16 W/m2K.

With CavityTherm you can achieve the Part L requirements without altering designs, changing familiar building methods or increasing the build footprint – all because CavityTherm works perfectly within a standard 100mm cavity.

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