Double Glazing on Listed Building

[MatthewC]

We're applying for Listed Building Consent on our 19th C stone built semi, to do various updates such as a gas boiler and central heating, getting rid of two 1950s fireplaces, laying flagstones on the kitchen floor and fitting new sash windows in place of a metal-framed French door with two windows (see photo) which is the new kitchen.
I've just been told that Conservation are recommending that the new sash window should NOT be double glazed as requested. I know that one is not usually allowed to fit a DG window where there is currently existing SG, especially in a sash, but I had the idea that for a brand new window there was no real reason why we shouldn't fit DG. Given that the windows are on the side of the building and not overlooked, and the current glazing is NOT historic glass, I don't even see why they should use the "reflective properties" as a reason.

I'm actually not too worried about using SG in the kitchen as there is an existing SG sash window which we are not touching, but will they now insist that we use SG in our new extension, for which we are about to submit an application?

Matthew
http://houseintheenchantedforest.blogspot.com/

 

[biffvernon]

'told that Conservation are recommending' is a bit short of being forced down one path. That window round the back is not the same as the front of the house and I'd be surprised if you fail to win the argument if you really want to. Of course not all double glazed windows are born equal and if cost is not the first priority you could even get dg units made up with hand made mouth blown cylinder glass as the outside sheet. Tatra glass in Loughborough would make these.

 

[Moo]

Has the CO actually visited the house?

 

[AMc]

Even with one single glazed window in the room the difference between the thermal performance of a good sealed unit and single pane of glass will be substantial. On a new window I would use DG.

If your extension is subject to building control then the Building Control Office & CO may well bang heads on the subject - make sure you get a written/email recommendation from the CO if it's important to him/her to use single glazed and get a written/email acceptance from building control before you go ahead and order it to prove they're both happy with it.

The cost differences between SG and DG at the point of making and glazing the window aren't significant but having to remove and replace a window that either authority won't accept would be.

 

[MatthewC]

Has the CO actually visited the house?

That's a good question - from her comments, I think she has, but she did not have the courtesy to ask me!

 

[keld]

Hi we've been told repeatedly (over several years) by our CO that they will not accept DG as replacement, front or back, to our listed building. Our neighbour who also has a listed building has had to replace with SG, we've just had our sash draft proofed.

Good luck.

 

[oxalto]

Matthew are you VOWH for planning?
The extension will come entirely under modern building regs, from what I understand, and DG windows will be expected and permitted. They will most probably want them to match in with existing windows, though, so no UPVC, not that you'd want that anyway! We were told that for our new / replacement windows in the historic fabric we would have to have matching windows in single glazing BUT secondary glazing was permitted. The building regs officer required secondary glazing. This can be achieved a number of ways, but the best I've seen is to have it built into the windows from scratch. See Biff's website for examples: http://www.biffvernon.freeserve.co.uk/oak_works.htm
This will give you many of the benfits of double glazing without falling out with the CO. (Melanie or Grant if you're VOWH)

 

[Manders]

This really annoys me and I see it a lot.

The decision to be taken by the CO/LPA is whether your proposal will have an impact upon the character of your building (it will hence LBC being req'd) and whether this impact would be positive, detrimental or neutral. From your photograph, I can't see why DG timber windows if correctly proportioned etc can't be seen as an improvement over the existing metal windows. Despite what you or the CO/LPA may want as the best option, if it makes the situation with regard to the character of the heritage asset no worse, it should be approved.

All that said, in the great scheme of things, if you have negotiated a 'deal' on the basis that you can have an extension providing that you make other items to the house better, the scheme will have been judged on not just this aspect but the whole scheme and without making the improvements to the main house you may not have gained consent for the other works. In which case its a whole different ball game.

 

[MatthewC]

This really annoys me and I see it a lot.

The decision to be taken by the CO/LPA is whether your proposal will have an impact upon the character of your building (it will hence LBC being req'd) and whether this impact would be positive, detrimental or neutral. From your photograph, I can't see why DG timber windows if correctly proportioned etc can't be seen as an improvement over the existing metal windows. Despite what you or the CO/LPA may want as the best option, if it makes the situation with regard to the character of the heritage asset no worse, it should be approved.

All that said, in the great scheme of things, if you have negotiated a 'deal' on the basis that you can have an extension providing that you make other items to the house better, the scheme will have been judged on not just this aspect but the whole scheme and without making the improvements to the main house you may not have gained consent for the other works. In which case its a whole different ball game.

There is no "deal" but I am well aware of annoying people with the first application so they get more picky on subsequent ones! My kitchen will have frames to take DG, probably fitted some really cheap glass which is liable to be accidentally broken (unfortunately) some time after completion... However, if they argue with my extension having DG, then I would take up the battle.

Matthew
http://houseintheenchantedforest.blogspot.com/