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Achieving Part L Building Regulations - Don't go thicker, go Smarter, go MMC!

Updated: Nov 29, 2023


Image shown is a BIM Model cut through of homes designed using the Etopia System.

The Revised Part L Regulations and WDQR-21 Regulations in Wales are causing issues for many developers and contractors.

Delivering schemes on the ground that achieve the new standards for airtightness and u-values are proving difficult, for several reasons, which I will consider below.

Some solutions focus on adapting existing traditional wall make-ups to bring them up to the right levels to meet regulatory requirements. This means adding several layers of insultation or other materials to the wall make up. This is leading to thicker walls (up to half a meter), relying on multiple layers of insultation, membranes, tapes, and seals.

Thicker walls cause conflict with planning permissions granted before the Revised Part L and are impacting on site density and viability. Room sizes are also being squeezed to accommodate thicker walls. We know that organisations are currently working with local planning authorities to determine how to achieve the performance without homes falling below the NDSS.

Adding more layers to a wall fabric increases the amount of time, labour and materials required, inflating costs and risk. Risk is introduced as every layer must installed correctly to ensure the final performance of the home, which will be tested.

It’s important that as an industry we don’t try to keep doing what we’ve always done, making cavities larger to accommodate more insulation. As we move closer to the Future Homes Standard, it’s going to get more and more difficult to adapt.

There are already products/systems of various types that enable the delivery of homes to the revised Part L requirements. The Etopia System is one of them. Our finished walls offer above Future Homes Standard performance at 262.5mm and do not rely on additional layers of materials, the panel is all you need! All homes at our latest development have achieved EPC A.

I’m delighted to say that I have been asked to speak at an event organised by Barclays in Cardiff next week to speak to developers and providers on how to deliver homes that meet or exceed the new requirements and offer high quality affordable homes that significantly reduce fuel poverty and the health and wellbeing of their occupants.


Nicola Clayton - Etopia


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