Listed Building and Double Glazing

[DavidO]

Does anyone have any experience or expertise re replacement of windows in Grade 2 listed residential buildings. I am considering a significant renovation job which is G2 listed. There is existing planning consent but it does not appear to include replacement of any of the windows. The statement in the approval document simply states “existing made good”. I can’t think why the planners or conservationists would want to retain the existing windows as they have no architectural or historical merit as far as I can tell (pics attached). To me they look like 1970s ish replacements complete with inappropriate lintel and sills. What does anyone think about persuading the planners to accept a tasteful, heritage sympathetic but energy efficient replacement (about 10 windows in total; similar story with all of them). Many thanks!!

[mjc55]

Hmm, difficult that one.  This as I understand it but others with more specific knowledge may be along to correct me later.

 

The point about listing is that it should stay in the style that it was at the time it was listed.  This is even if, to some, the style of any part of the building is ugly, inefficient or not up to current standards.

 

It may be that there are more efficient windows around that match the style of your windows, I don't know.  Again, others with more knowledge in this area may well be along to suggest what you might do.

 

Conservation officers have a difficult job as many people want to upgrade to modern standards, but their job is to maintain an "historical" building in the manner to which it was listed (not built).

 

I suspect that a conversation with your local CO would help.

[Nickfromwales]

Find some sample images of houses with the same windows in that you are considering, then send the questions and ask directly. 
 

Often depends which way the wind is blowing, unfortunately. 

[garrymartin]

Take a look at https://historicengland.org.uk/images-books/publications/adapting-historic-buildings-energy-carbon-efficiency-advice-note-18/ released in February 2026.

 

I also recently learned about vacuum double glazing when I was looking at similar issues on listed buildings. Might be of interest if you can't get approval for standard double glazing.

 

https://www.vacuumglazing.co.uk/landvac-enhance-heritage-vacuum-glazing/

 

 

 

 

 

 

[garrymartin]

Oh, also, something else I learned on Buildhub from @Dan1983 is Astragal bars which are decorative, surface-mounted strips applied to both the inside and outside of double or triple-glazed window panes to create the authentic, subdivided appearance of traditional small-paned Georgian windows. They might be useful for your situation, given your original images.

 

[DavidO]

Very interesting Garry, thank you! The landvac u value is amazing for that thickness. Do you know how it compares from a cost perspective?

[DavidO]

mjc ……> The point about listing is that it should stay in the style that it was at the time it was listed.  This is even if, to some, the style of any part of the building is ugly, inefficient or not up to current standards.

 

Even for bland 1970s windows made of poor quality timber??? As a decade it was probably the high point of my life, but certainly NOT of either architecture or building standards. What is the logic of preservation of crap and perpetuation of environmental wastage?

 

[JohnMo]

4 minutes ago, DavidO said:

Even for bland 1970s windows made of poor quality timber???

That the joy of owning a listed building - don't want to play by the rules, don't buy listed.

 

6 hours ago, DavidO said:

There is existing planning consent

Don't confuse planning consent, with listed building consent. You need both. Planning consent is easy, list building consent will turn you grey especially if you don't want to play by their rules. 

 

9 minutes ago, DavidO said:

preservation of crap and perpetuation of environmental wastage

There are ways do things and do them well and still comply with listed rules. But you need to keep the listed folk on side. And have deep pockets.

[Mike]

7 hours ago, DavidO said:

they look like 1970s ish replacements... What does anyone think about persuading the planners to accept a tasteful, heritage sympathetic but energy efficient replacement

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.

[garrymartin]

3 hours ago, DavidO said:

Very interesting Garry, thank you! The landvac u value is amazing for that thickness. Do you know how it compares from a cost perspective?

I don't have detailed comparisons, but my understanding is that depending on various factors, it can be 50% to 200% or more expensive than standard double glazing. If you're really restricted from a listed building approval perspective, that may be something that's financially palatable though.

[saveasteading]

I've replaced critall with a dg lookalike on our listed building. It looks the same which is what matters.

[Roundtuit]

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.

[saveasteading]

The skinny window bars is all that matters for the retained appearance. So the modern equivalent has exactly the same appearance with main frames  matching your main sections, but infilled with single panes, rather than multiple small ones, and dummy astragals inside and outside.

[saveasteading]

This is Rationel . Otherwise look for "heritage".

[Susie]

It would be wise to check with your local window supplier first.

we looked into this for our windows and rational and heritage both offer windows that are in other listed buildings around the country. Our local supplier came out to quote and see which would most likely be accepted by the local council. It turned out neither, the supplier is in Devon we are 10 miles inside Cornwall, he said he had installed many alternative 2G and 3G windows in Devon but Cornwall would never approve them. 
Our converted barn was converted in 2000 from a disused and half falling down barn, we are part of a larger group of buildings (same curtilage) with the farm house being the reason we are listed. Our listing for all the barns mentions windows of 6 panes, nothing more architectural. The windows still need replacing but the funds are needed elsewhere.  I’m hoping one day Cornwall council listings will change their mind.  

[saveasteading]

58 minutes ago, Susie said:

Cornwall would never approve them. 

I'd be asking them to specify what they require. They cannot insist on one supplier, crittall. 

When these Rationel heritage windows were launched both we and our window contractor saw them  and thought ahaa, that's the answer. True enough the listed buildings architect approved them, having previuosly stated "only crittall". About 10 years ago?

We also used an off the shelf door with skinny bars, but I made out it was special.

It is usually worth the effort of a fancy presentation.