Insulation testing and using the right products can save developers and homeowners thousands

Published in Technical Specification on: Wed, Jun 20, 2018 5:03 PM

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A builder has saved thousands of pounds constructing seven timber frame new builds by using super effective insulation to achieve a 19% - code level 4 - Co2 improvement over the current building regulations instead of costly renewables.


Adam Jones, who runs Custom-Built, is building the detached five bedroom homes in Warminster – and originally planned to install solar PV panels to ensure he achieved the correct SAP rating.

However, building regulation specialists Energist came up with a more cost effective alternative after studies showed that using Actis Hybrid products could generate some of the best Y-values ever achieved.

The original insulation specification meant that as well as achieving a U-value of 0.19 in the walls he would need solar panels in order to pass the SAP assessment and reach level 4 in the Code for Sustainable Homes for the energy category Ene 01.

But using the results of an in-depth thermal modelling trial carried out by BM TRADA, Energist showed that using Actis Hybrid would enable him to achieve the required rating with waste water heat recovery, but without the addition of solar panels.

The advice was based on a combination of a BM TRADA thermal modelling trial carried out in 2016 on the Actis Hybrid products and the results of a follow up SAP exercise which showed they have a dramatic impact on counteracting thermal bridging and act as excellent thermal blankets.

Interestingly, the test showed that using the actual psi values calculated by BM TRADA created a far more thermally efficient building overall than using government prescribed default psi values.

Adam used 3,420 sq m of insulating breather membrane Boost ‘R Hybrid and 105mm honeycomb style insulation Hybris in the walls and 1,143 sq m of insulating vapour control layer HControl Hybrid and 170mm Hybris in the roofs.