Window glass change - permission required?

[Notch7]

Those windows look like theyve been glazed with face putty.

that’s going to be a real nightmare to do - you will spend most of your time trying to get rock hard putty out of the rebates. You won’t get a tradesman interested in trying to do the job.

your 2nd problem is the rebates will only be around 10mm and standard double glazing needs 12mm spacer + 4mm air gap min.

if you choose slim line glazing, you will suffer premature failure of the units - unless you really know how to fully encapsulate properly.



Your best route is to simply replace the sashes - in which case the rebates could be tweaked to suit your new glazing.

 

[Notch7]

I will just add: the glass might be fitted with glazing sprigs which won’t all come out so trying to make the rebate bigger will write off TCT router cutters.

 

[Diver Fred]

I will just add: the glass might be fitted with glazing sprigs which won’t all come out so trying to make the rebate bigger will write off TCT router cutters.

100% agree.
I've never known single glazed lights to not have the glass retained by sprigs.

 

[trojan_build]

Thanks - that's a good video - exactly what I needed.

There are approx. 75 frames to do, plus 20 small lights, so I can't afford to get a joiner in to remake the frames. I've got some good woodworking kit and plenty of time, so this might be one for next Spring ...

 

[trojan_build]

Glazing sprigs - yes, they are definitely in there. Something else to avoid ...

 

[ronniecabers]

You could get ' stepped ' units , where the outer pane sits in the same place as the current single glazing , and the then the inner would be within the sash, probably about a 15mm step all the way round. You'd just need to get a bigger bead outside to cover the sealant and then a small bead Internally to cover the sealant seen from inside ( you don't have to bead inside, I've seen the glass painted before now

 

[trojan_build]

Any advice on how these sashes are jointed at the corners? They all feature a mortice and tenon joint, but are they
glued, pinned, or glued and pinned?

If they can be knocked apart without damaging the timber, one option is to run them through our bench saw to create the new rebates - nice and neat once dimensions are set. We'd need to add some timber fillers on two sides to compensate for the wood cut, but easily done, and then reassemble.

 

[mrrusty]

IMHO The easiest way is to either buy or make up some new sash profile - it's readily available, although you might need to tweak a standard profile to suit your frame e.g. https://www.cwberry.com/square-storm-sash and make new sashes

The joint could be a bridle joint, mortice and tenon, or just dowelled and glued. Once you get your head around how to make the joints, I think it is a far easier/quicker solution than trying to fettle the existing.

 

[RrogerD]

Personally, I think that what you're proposing, is a sin. You'll have changed the whole look and character of the building to something of questionable taste imo.
Why do you not instead, fit double-glazed panes as you propose but with integral Georgian bars. All thermal characteristics will be the same, as will the ease of cleaning both inside and out.
Not to be confused with external face leaded-bars which are frankly a nightmare.

 

[trojan_build]

Hi,
Thanks for this - all views appreciated.

Your point about changing the appearance is well made, and we've wrestled with this and sought the opinion of others. It's a difficult call. The frames are not historic - that are probably from the 1980s.

I've never found internal bars attractive. They would be plastic and would appear well out of place on this house.

Our house is somewhat dated. Two of the toilets are carpeted, and so is the kitchen. We want to make it more contemporary, and especially make it easier to maintain and better thermally.

There are approx. 750 individual panes of glass in the house, each puttied into timber - it's a big place. Assuming one coat of primer/undercoat and one top coat inside and out, that's 3km of edging (ouch!) that needs to be painted, ignoring the putty repairs. It really is the old Forth Bridge proverb.

The photos below show what it looks like now and what it may look like when converted. There is huge gain in doing this, but as you say, appearance is also important. The countryside views from inside the house would be massively improved.

Quite difficult for us to have a non-biased view on this - we are now so used to it as it is.

If the house didn't have the Georgian bars from the start, you probably wouldn't think about it - most houses don't have them.

Would value any opinions on whether you consider the appearance to be better or worse ...

 

[mrrusty]

That's big. Not just a single window then! I don't think it looks bad at all without the georgian bars, although they do add a certain "character".

I think the first question is what are your plans for the next 10-15 years - are you staying there? or planning to move? because IMHO that really dictates the best solution. If you intend to stay I think mucking around cobbling new sashes in to all the old frames is not the solution - it could be done but you'd need a pro to do it in a joiners shop, and I doubt you'd save much. If it was a single window, or even 2-3 I'd probably DIY some new sashes, but I don't think I'd do that many - especially as they would all need paining which I hate.

I think you have two choices - cheaper - uPVC throughout - or, more (very) expensive, top quality timber (maybe accoya) windows. If you intend to sell, I think I would be looking at inexpensive secondary glazing and leaving it all well alone, because I doubt you would recover the investment.

 

[trojan_build]

Thanks - a good viewpoint. Timescale - not certain how long we will be here, but minimum five years, and probably ten.

I have a good range of woodworking kit, and I'm pretty confident that I could reconfigure existing sashes to take 4-6-4 sealed units, and some shashes will take 4-8-4 or even 4-10-4. No rush to do this - one step at a time in between other tasks.

I don't think that uPVC would work here - quite likely that it would degrade the property, unless we opted for top of the range units. There are also other alternatives, eg coated aluminium, but the cost would be horrendous.

I quite like the idea of reusing the old frames. It's good for the planet, relatively inexpensive, ignoring my time, and timber windows does suit the property. Whatever we opt for, the key is future maintenance.

Yes, it's a big property. Below is the front elevation, existing and proposed.

Thanks again for your input - appreciated.

 

[mrrusty]

Honestly, reconfiguring existing sashes is IMHO a very challenging option, and IMHO the work required doesn't justify the saving. I made 7 box sash windows with DG for our house in Accoya. I bought a band saw, cheap (screwfix £150) thicknesser, router table, and a domino 700 for joints - about £2.5K of kit at the time, but even in Accoya the complete windows didn't come out much over £600ea (about 1/3rd the price of commercially made accoya sash windows) including tool costs (which I still have of course).

Accoya is really good for windows - it's very straight, doesn't move about at all, machines easily, and paint lasts a long time - I used Teknos (sprayed) which when used professionally offers a 10 year warranty on Accoya (not DIY of course). You can get Accoya from Arnold laver, but you do have to convert it - hence the band saw and thicknesser. It comes as very straight, reasonably fine surfaced rough sawn. The router table means you can make all the rebates and profiles to suit. It took me in the order of 250 hours in total to make 7 box sash windows. The DGU were dry glazed into the sashes and internally beaded.

 

[Diver Fred]

You certainly have a job on your hands.
I'll not be negative but there are a few things to think about. As you work around the house windows you do need to check the integrity of the casements and the lights,if any of those are suspect then consider replacing over repair.
As you have Stormproof lights the rebate in the casementa will be 38mm deep so any replacement lights will also have to be Stormproof profile which leads into another consideration. The frame of lights, fixed or opening, sides an head will be made from 2x2 PAR which depending who machined it could be 47x47, 47x44 or 44x44on final size. The bottom rail will be from 3x2 or bottom ligjhts or 2x2 for transom lights.
The machining you will do to either existing or new timber means a lot of the timber strength will be cut away. The fireproof rebate will be 38x12; the glazing rebate thickness of the DG unit plus 12mm (allowing for 8mm bead and sealing strip).
I'm not in a position to supply an image of the final cross section of the wood unforunately.

Nowadays I cut the rebate on a tablesaw rather than route out or machine on a jointer. Cutting on a table saw will give you the material for the beads.

 

[Notch7]

Any advice on how these sashes are jointed at the corners? They all feature a mortice and tenon joint, but are they
glued, pinned, or glued and pinned?

If they can be knocked apart without damaging the timber, one option is to run them through our bench saw to create the new rebates - nice and neat once dimensions are set. We'd need to add some timber fillers on two sides to compensate for the wood cut, but easily done, and then reassemble.

I think you would really struggle to knock them apart without destroying them

They will all be scribed tenons and glued