Listed Building and Double Glazing

[Stu789]

We've experienced a high failure rate of small DG units with narrow edges to suit narrow window bars in our G2 listed house (hardwood casements, sash and doors).  If going that route I'd suggest check on guarantees and ask around for customer experience over the medium term.

Our CO is pretty reasonable - like for like work, email conversation only.  Changes to any detail put in listed consent (no charge) with drawings and a sensible rationale - been no issues.

 

Good luck!

[DavidO]

On 13/03/2026 at 21:10, Mike said:

They do look 1970's, but roughly like copies of Crittall windows; I wonder if that's what they replaced?

 

Since they look similar, there may be a chance of persuading them to let you install similar new Crittall windows, on the grounds that they'd be more authentic (as well as being better insulated). If you can find old photos that substantiate my suspicion it would help.

Interesting thought Mike. My son thought that the windows prior to these 1970s/80s timber (not the originals which would have been something like 200 years ago) might have been metal windows (so could possibly have been Crittals…?). I will see if I can get some pre 1960s photos from our local historical society!

[DavidO]

On 14/03/2026 at 00:05, Roundtuit said:

More details of the period and listing would be useful, but I'd suggest that the width of those openings isn't original so any replacement will be equally 'unauthentic', if visually more pleasing. If you're also in a conservation area, what's in adjacent buildings may also have a bearing.  Have a chat with the conservation officer, some of them are almost half-reasonable.  Failing that, secondary glazing is actually pretty good.

Thanks Rt.  You’re correct about the openings. It looks to me that when these 70/80s frames were installed they also widened the openings and put it new sills and lintels (cast concrete..!!), presumably in order to get more light into what were then offices (the local council ironically!). If you look either side of the lintels you can also see that they must have removed part of the decorative course of bricks below the gutter in order to accommodate oversized lintels? Almost vandalism…but council workmen were empowered to do whatever they liked in those days!

[DavidO]

[DavidO]

On 14/03/2026 at 21:45, Susie said:

 

To clarify Cornwall planning/conservation will not allow PVC windows in listed buildings even if very good looking like wood they want wooden frames or as original.  Im hoping one day this will change but whilst we are building our new home we have no spare funds for our current home. 

We have factory built/painted wooden framed double glazed windows in our current (self built) house which were installed 14 years ago when we built which haven’t even needed a lick of paint since and are clearly not deteriorating at the rate that many UPVC windows do. Allan Brothers, Berwick on Tweed; they supply nationwide…even Cornwall. They also do a heritage range of similar construction.

[DavidO]

On 16/03/2026 at 07:34, saveasteading said:

I hadn't heard of that argument. That is becoming rather desperate as an argument for crittall. 

Presumably then, the better made a crittall is, the less this happens.

I do understand the argument….and partially sympathise…but only partially, and I don’t think that retaining wavy glass is worth the compromise in energy efficiency, especially in a building which has already had so much of it’s historic value desecrated by the (former) local council 🤭

[DavidO]

On 16/03/2026 at 08:17, SteamyTea said:

Get elected, promoted, into the right committees, then give up.

Or just sell up to the National Trust, it is what our council does. 

 

  

I was taller.

My platforms were red…😂