Single glazed sash windows noise & draughts

variable_luck

Hi,

I recently purchased an upper flat in a conservation area. The front of the property faces a main road which can be quite noisy. There are 3 large windows to the front which are all original sash windows with working shutters etc. However - although they look lovely they are draughty and let in a lot of noise. I initially looked into secondary glazing but I felt this looked a bit ugly and it also would prevent use of the shutters. I then spoke to a local joiner who said that the best thing to do was to draught proof the windows and replace the glass with so called "acoustic" glass. He provided a reasonable quote for this when compared to what they wanted for secondary glazing. He additionally claimed that replacing the windows with new double glazed ones was not a good idea as it would devalue the property (replacing the original windows would be a turn off for anyone who liked the period features) and that since it is in a conservation area, the thickness of the double glazing would be so thin that it wouldn't be worth it.

I suppose he would say that - but is he right ? Does anyone have any experience of a similar type of work, what difference does acoustic glazing make when it can only be single glazed ? Is there a decent reduction in noise from draught proofing and acoustic glass (even if it is only single glazed) - is the joiner correct about the double glazing etc ?

many thanks..

cattie

I can't answer some of your queries that relate to acoustic glass & sound reduction, but can confirm that fitting standard double glazing could devalue your property. However, there are some companies which specifically offer a double glazing service for period properties, which of course works out more expensive than the run of the mill double glazing that is fine for the majority of properties, so it might be worth your while trying to source such a company for advice.

I've owned properties in 2 different conservation areas, both with the original windows, which I elected to keep. However, they were draughty & whilst I did have heavy lined curtains to help keep the draughts out, in the winter I would stuff the gaps in the window frames with bubble wrap, which did make a difference. Also, on windows that were a suitable size, I bought some of the glazing 'film' that you seal with a hairdryer, rather like clingfilm. This did a pretty satisfactory job at keeping the draughts out.

I can't see that any remedy that involved only single glazing would be satisfactory at all from an insulation point of view as double glazing is successful because of the gap between the panes, as well as type of glass chosen, ie A rated etc.

I've not heard of the glass used in conservation areas having to be thinner that that fitted in non conservation areas, so would take that with a pinch of salt I think.

variable_luck

Many thanks for your reply. re. the thickness he said that you need to apply for planning permission and it can be a long process. The city council have guidelines stating that they prefer you not to replace the original windows unless they are un fixable (they aren't that bad) so they might not even give approval to get double glazing put in (this appears to be true from reading up about it on their website), i can't tell whether any of the properties in the neighbourhood have DG or not, our immediate neighbours do not however.

leveller2911

The options are limited by the Planning regulations for the Conservation area and whether or not the property is Listed.

If its not Listed then the OP has the option of renovating the existing windows and adding draught excluder and glass, although I don't see much benefit to replacing the glass unless its DG units and that can add problems with weights. "Acoustic" glass imo doesn't add much benefit for the extra cost. You will never make old sash windows draught proof even with the best type of draught stripping but you can reduce the amount of draughts. I'm not sure you can use Acoustic glass as single glazing and if your Joiner is looking to use 6.4 laminated glass (2 panes of 3mm with 0.4mm of membrame between) then this will make little difference unless its in a DG unit.



If the existing windows are in poor condition (rot,twisted sashes,loose joints) then you need to weigh up whether the cost is worth it longer term or better to replace now with like for like bespoke windows with integrated weatherstripping and DG.

Some Local Authorities will allow relacing the windows with single glazed ones only, especially on the front of the property and some will allow double glazed. Some who allow DG will only allow "slimlite" double glazing which is very expensive compared to other DG systems such as "Duplex"...

Does replacing existing single glazed sash windows with DG ones de-value a property?. In my opinion no it doesn't as long as the new windows are exact replicas of the existing ones. In fact from my experience it adds to the value because prospective buyers can't look to knock you down on price because they wish/need to replace the windows in the future.

Just to add: If the Joiner has quoted for 6.4 laminated glass I hope he has considered the extra weight of the sashes. As an example a 1 metre sq pane of 4mm glass will add an extra 22lbs of weight to the sash so he will need to add 12lb of weight to each side of the box for each sash. That extra weight needed means he will need to use far taller weights (iron) or wider weights (lead) and the pockets that you have to fit the weights in need to be wide/tall enough to take the increased weight.

There is a lot to consider when carrying out this work.

variable_luck

Hi Leveller, the property is listed. Two of the panes of glass are cracked so will need replacing one way or the other, the question i guess is whether to go for the acoustic glass. It would cost an extra £130 to get the acoustic glass as he would need to add extra weights etc. Given the size of the panes of glass we are talking about it doesn't seem that much of a difference for just the one at least. The other 4 panes at the front don't really need replaced as they're not cracked, it would just be for insulation. He also said that draught proofing would hopefully reduce the noise as well. I should add here that there are vents which are permanently open which cannot be doing anything for either noise or heat insulation, these appear to have been fitted onto the original window but IMO it was not a good job, this is another thing he said he woulf fix.

leveller2911

variable_luck wrote: »

Hi Leveller, the property is listed. Two of the panes of glass are cracked so will need replacing one way or the other, the question i guess is whether to go for the
acoustic glass.

If its Listed what does the Conservation Officer say?.

It would cost an extra £130 to get the acoustic glass as he would need to add extra weights etc. Given the size of the panes of glass we are talking about it doesn't seem that much of a difference for just the one at least. The other 4 panes at the front don't really need replaced as they're not cracked, it would just be for insulation.

What does the £130 actually pay for ?. Is it for the "Acoustic glass and weights" only?. What brand of "acoustic" glass does he intend to use or is he actually going to use 6.4 mm laminated glass and say its "acoustic". This is the tricky part in not know what he intends to use.



Has he quoted to "Overhaul the existing window including replacing the existing glass with "Acoustic" glass, add weights, re-cord, replace pulleys,sash fasteners etc"?.

He also said that draught proofing would hopefully reduce the noise as well. I should add here that there are vents which are permanently open which cannot be doing anything for either noise or heat insulation, these appear to have been fitted onto the original window but IMO it was not a good job, this is another thing he said he woulf fix

Fiting draught excluders should help thermally but acoustically it won't help that much due to the fact that the brush piles etc they use are very thin.

When you say "vents" do you mean "Trickle vents". If so they will let in lots of noise and draughts. I'm surprised someone has retro fitted them as thye make no difference, better to just open a window if people want to air a room.

Really difficult to know if you're getting a decent quote without knowing more facts.


I would get some quotes to replace as well as renovate , at least then you can decide on the best option. If you are intending to stay long term I would def consider replacing with DG ones if you are allowed by the Conservation officer. The Joiner may try and guide you down the renovation route if he doesn't make windows and just overhauls them.

Its a bit of a can or worms when its Listed .

dominoman

Acoustic glass does make a difference, especially for high frequency noises. It won't do anything for the low rumble of lorries etc. It works by sandwiching a thin plastic layer inside the glass pane, which dissipates energy

For the sake of a few extra quid I would get acoustic glass for the window panes that need replacing.

The other thing that will make a difference is using the rolls of sash window insulation tape around the edges. You can buy it in B&Q or online for around 10-15 per roll, which should do several windows.

I have original single glazed sash windows too and wouldn't change them for anything. I love them!

leveller2911

dominoman wrote: »

Acoustic glass does make a difference, especially for high frequency noises. It won't do anything for the low rumble of lorries etc. It works by sandwiching a thin plastic layer inside the glass pane, which dissipates energy

Thats my point, traffic noise is low frequency noise and standard laminate glass is exactly the same make up so 3mm 0.4mm membrame and 3mm glass. The best way to reduce the noise is a DG unit with different thicknesses of glass so 4 mm and 6mm .

I have original single glazed sash windows too and wouldn't change them for anything. I love them!

But what are "original" sash windows?. I make and fit lots of them and I regularly work on houses where they have "Georgian looking,Early Victorian,late Victorian,Edwardian" etc so in reality the only originals are the windows that were made at the time the house was constructed. All subsequent windows are copies of the originals or changed when the fashions changed.

Throughout the centuries windows have been replaced and no reason why they can't have windows made to exact replicas of the existing ones. Even making exact replicas with DG can look great and no one would notice the difference unless you satnd 2ft away and even then it can be difficult to tell.

The problem is the cost to make bespoke replacements.So when people can buy a standard window from Jewsons that looks similar to a sash window but bares no resemblance to the original then they look awful but they think its fine.

variable_luck

I've tried to contact the council to inform i need to replace the glass in at least one window. It's B listed in Scotland whatever that might exactly entail. My naive understanding of it is that you can replace the glass but not the window frames and surrounds, the apparent aim of the policy is to preserve the character of the area and all that, the glass in some panes at least is not original, some of it may be I'm not sure.

leveller2911

variable_luck wrote: »

I've tried to contact the council to inform i need to replace the glass in at least one window. It's B listed in Scotland whatever that might exactly entail. My naive understanding of it is that you can replace the glass but not the window frames and surrounds, the apparent aim of the policy is to preserve the character of the area and all that, the glass in some panes at least is not original, some of it may be I'm not sure.

I'm not the best one to comment on the Scottish Listed system but in England... In England you're not suppose to even repair them without informing Conservation but in reality people do. No way the Conservation officers can police thousands of Listed properties.

Just replacing the glass is fine . If you go down the replacement route then get advice..

variable_luck

Thanks, i'm thinking that we might try this out on a single window in it's own room with heavy wooden door, so should be a fairly isolated experiment. It'll cost about 400 to draught proof and replace the two large (cracked) 4mm panes on that one window with acoustic, we can see how effective that is and take it from there I think.