Changes To Part L – Too Far Or Not Far Enough?

People at a podcast

Now that the new Building Regulations have been published, AluK has asked a range of people what they make of the new rules and whether they think they go far enough.

The people had all contributed to a podcast back in October 2021.

The Regs see a reduction in notional U-Values for windows and glazed doors in new build homes to 1.2 and limiting U-Values of 1.4 for replacement windows and glazed doors in existing homes.

From AluK’s point of view, head of process and certification, Dale Pegler said: “The changes are broadly in line with what we were anticipating, albeit with a few surprising additional amends within the released document. However, AluK is already well on the way towards ensuring we have a full range of product options which comply with the regulations. We would perhaps have liked to see some mention of the assessment of embodied carbon in construction materials because environmentally, this is just as significant as thermal performance – and of course, aluminium is a 100% recyclable material.”

 

An architect`s view

Mark Taylor, technical director at architects Allies and Morrison, welcomed the lowering of the U-Values in the notional dwelling but shared the view that the changes could have gone further. He said: “The U-Value of 1.2 represents only a small improvement on where we are now, yet we can all see the direction of travel. At least there’s a bigger incentive now for architects to calculate the psi value (which is heat loss per metre at the edge of the glass) and that’s a more accurate reflection of the true performance of the window.”

 

Glass

By contrast, Gareth Allen, technical and training manager at Saint-Gobain Glass, felt that the pace of change is probably about right in terms of moving towards the government’s target of a 30% reduction in carbon emissions from new homes. He said: “What came out of AluK’s podcast was an acknowledgement that some sectors will find it harder than others to comply even with this fairly conservative shift to 1.2 for new dwellings and 1.4 for existing. Saint-Gobain Glass is certainly committed to doing our part to support the whole industry on that journey. We’ve already got products available which will help with compliance, and we’re seeing a return to normal stock levels.”

 

Right pace

John Miles, from Assent Building Control, agreed that, given the fragility of the construction sector at the moment, the new Regulations will deliver the right amount of progress at just about the right pace. One thing he pointed out though was the relative lack of pushback from the industry on the changes, suggesting perhaps that many had actually expected the notional U-Values to be lower. He did say that, in practice, many architects are likely to specify U-Values for windows which are lower than 1.2 if they are using SAP calculations to balance glazing with the overall efficiency of the building fabric. This, he added, is likely to lead to more widespread use of triple glazing in new build, very much in line with the thinking during the podcast.

Miles also warned that the transitional arrangements are not as generous as many people think, saying: “Only plans for projects which have already been approved are likely to come outside of the new rules. In reality, fabricators and installers will need to be making the changes now ready for projects which start after June 15.”

 

GGF

Kevin Jones, the GGF’s technical officer, confirmed that the Federation is in contact with the Department for Levelling Up, Housing and Communities to give feedback on the published document but remained confident that the industry will rise to the challenge.

Picture: Some of the original contributors to AluK`s Part L podcast in October 2021.

www.alukgb.com/learning/fhs

Article written by Cathryn Ellis
10th February 2022

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