We mentioned in last week’s blog piece on the Future Homes standard that we’d come back with further detail and commentary in due course and the changes that are afoot are substantial, but one implication will be that life gets a lot more difficult if you’re looking for large glazed areas.
Apart from the basic difficulty of compensating for the relatively massive heat loss that these present, the Regulations are also beginning to recognize and take better account of overheating risks form large glazed areas.
A new Approved Document X sets limits on glazed area, beyond which special design measures will need to be applied to prevent overheating. Interestingly, these are much stiffer in Greater London than in the rest of England, with the London limit on glazed area being set at 13% of floor area, versus 21% elsewhere in London.
Now, we can tell you from experience that it’s not difficult at all to exceed 13% glazed area, and exceedingly easy where clients request fashionably large bifold doors, so it looks like we’ll need to start thinking much more carefully about whether we can ‘afford’ these (in design terms) in the future.
The good news for bifolds is that, at the moment, it looks like those special design measures may need to be nothing more than the ability to open up enough of the glazed area to be able to disperse the heat build-up, but it remains to be seen how much of a problem the additional heat loss will present. It will be interesting to see whether this will mark the start of a shift away from large areas of glazing on domestic dwellings. The draft Approved Document X does not yet include any proposed Limits on Application, so we can’t be sure yet whether this will apply only to new builds, or whether extensions and alterations will also fall within its scope.