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The Regs: Part L changes

Part L reform could remove exemptions for historic buildings, says Geoff Wilkinson

In the run up to the Copenhagen climate summit, we have seen a rush by all the political parties to show their green credentials with headline announcements on ‘green deals’ and ‘boiler scrappage’ schemes.

At long last, there seems to be recognition that, no matter how far we take Building Regulations for new construction, we will fail to tackle global warming until we do something about the existing building stock. This is great news for the energy conservation groups, but what effect will it have on heritage conservation groups?

Window manufacturer Crittall has recently started a campaign to highlight the proposed changes within the Part L consultation documents that were released earlier this year. The current Part L includes exemptions for heritage buildings that were taken from the Energy Performance of Buildings Directive, but which are optional.

It is proposed that some, perhaps all, of these exemptions be deleted because they overlap with the general exemptions to the Regulations, and this has caused confusion. It is proposed that this exemption be removed, but specific guidance be provided in the approved document as to where special considerations apply, and how to arrive at an appropriate balance between heritage and energy conservation. However, it should be noted that the current exemptions for historic buildings are conditional on the nature of the work, and that these buildings are not exempt per se.

The consultation document indicates the need to consult the local authority conservation officer, but with planning applications down by almost 30 per cent and pressure on public finances, not all councils will be able to retain a dedicated post for this function after April. This will put the ball firmly into the court of the building control officer to decide on the balance between the two factors.

The Crittall campaign rightly focuses on window replacement as this is one of the most important areas of building conservation. English Heritage is quite clear that ‘window openings establish the character of an elevation; they should not generally be altered in their proportion or details’.

This is English Heritage’s stance in 90 per cent of appeal cases for replacement windows, with the appeal dismissed because the replacement would detrimentally affect the character of the building.

Conversely, window replacement can generate energy savings of 20 to 40 per cent in pre-1970 buildings, and is one of the most popular home improvements, with an estimated two million replacement windows installed each year. This creates a huge problem for clients who are caught between differing interpretations within local authorities. To make matters more confusing the majority of window replacements will not be inspected by either the local authority building inspector or the private approved inspector, having been certified by the installer under the FENSA industry standard system.

It is too early to predict just how the balance of power will finally rest between planners and building control until the final draft of Part L is released in April 2010. In the meantime, I would recommend that anyone working on heritage projects seeks to gain approval before October next year when the revised guidance will take effect.

Geoff Wilkinson is a building regulations expert and former vice-chair of the Association of Consulting Approved Inspectors (ACAI)

Readers' comments (2)

  • Windows can be improved without being replaced, so energy savings can be made without affecting the character of a building. Depending upon quite what the upgrading measure is, acoustic performance can be rather better than any double glazed system (which could be beneficial in most older buildings because they tend to be closer to noisier roads). An added bonus is that historic glass can be retained too.

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  • English Heritage has done a research with Glasgow Caledonian University which shows that simply repairing a sash window can cut draughts by as much as one third, and that adding draught proofing can cut draughts by up to 86%. Do check out more details from

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