Part L has been revised several times since the turn of the millennium, but this is a more momentous change as this is the first time Part L is being split in two: There will be one version to cover England and a separate version for Wales. Details for the English version were released last year, but the Welsh updates have only been announced in the past week… here are the headlines: For the new-build domestic sector, there aren't too many changes to be concerned with – the majority of updates within the Welsh Part L are the same as what has already been announced in the English version… but there are definitely some things which are noteworthy...
Firstly – the date. Welsh Part L goes live on July 31st with the same transitional arrangements as previously. This means that, if you submit your details to Building Control on July 31st or after, you’ll be expected to build to the new Part L. If you get your submission in before this date, you are allowed to construct to Part L 2010 providing you start work on site within twelve months.
In England, the cut-off date is April 6th. The new Target Emission Rate is being calculated in a completely new way – a technique called the ‘Elemental Recipe’. This is a published specification which, if followed to the letter, will meet compliance with the new Part L. The specification definitely isn't everyone’s cup of tea, but developers have the flexibility to come away from this ‘Recipe’ and make details worse, providing they make improvements elsewhere. The Elemental Recipe is going to be the same for both England and Wales, which means the Target Emission Rate shown on SAP will be the same regardless of country. There had been concerns among builders who work along the border towns that they would need to develop more efficient specifications for their Welsh developments.
Another big change is that all maximum U-Values in Wales are being lowered. This means you’ll need to include higher levels of insulation to ensure you meet these enhanced targets. The new Values to newly built dwellings will be: For heat loss floors, the U-Value is reduced from 0.25 to 0.18 For heat loss walls, the U-Value is reduced from 0.30 to 0.21 For roofs, the U-Value is reduced from 0.2 to 0.15 For glazing, the U-Value is reduced from 2.00 to 1.60 This is going to come as quite a shock to a lot of developers, many of which have come up with ways of using a lesser specification for the fabric, and making up for additional energy use by using more efficiency services (heating / ventilation etc).
In England, all U-Values have been left at the 2010 standard, and instead a Target Fabric Energy Efficiency (TFEE) has been imposed to force developers into using lower U-Values. This will allow design flexibility, as it lets you decide which values to improve upon. Because Wales has opted for these much lower U-value requirements, there is not going to be a TFEE requirement as well. (But you will still have to meet the Target Emission Rate). The full set of Welsh building regulations for Part L, including the new Elemental Recipe, are available from the Welsh Assembly website.
For more details about Part L and how the changes may impact you, contact Energist UK on 08458 386 387