Encapsulating leaded single glazed window panes

[mjl34]

Dear all,
I wonder what folks' views / experience would be on the above? I have a number of superb leaded windows with a wonderful variety of glass textures in leaded panes that I am not willing to lose from my 1928 property. However, they are cold, suffer from severe condensation, and consequently from mould growth (also any ideas on removal of this mould / prevention, gently with an old toothbruch and water works but is there a better way / a more preventative approach I could take using a fungicide or similar - without causing any damage?). One approach is to seal the panes within a conventional sealed double glazed unit. I guess this sorts the thermal side of things, and means not losing the glass but surely won't look as good as the panes as they are as some texture will be 'hidden' away. Dilema! Your more experienced views would be very welcome please.
Mike

 

[biffvernon]

There's a pretty straight-forward solution, at least in theory, to this problem, tried and tested in many cathedrals and churches where the conservation of medieval glass is required.

You need an new sheet of glass (it could be single glazing or a double glazed sealed unit if thermal insulation is important) on the outside. This gets the rain on it. The old leaded light is then suspended indoors a couple of centimetres inside the new glazing, but, and this is important, there is a gap left open at the bottom and the top so indoor air can circulate behind the leaded light. The temperature and humidity will be the same on both sides of the light so there will be no condensation forming on it. If the new outer glazing is a double glazed unit there won't be any condensation there either.

The method is called 'isothermal glazing'. If you Google that phrase you will see lots of examples.

I would not recommend encapsulation.

 

[Tom]

However, they are cold, suffer from severe condensation, and consequently from mould growth (also any ideas on removal of this mould / prevention, gently with an old toothbruch and water works but is there a better way / a more preventative approach I could take

You could try improving the air circulation to reduce the condensation and, therefore, mould growth.

 

[Andrew Bodenham]

mjl34,

A few years ago I made an oak door for a customer. She'd made some leaded panels for it, and had them encapsulated in d.g. units. They have actually worked very well, and with the light coming through it's hard to tell from a distance that they are encapsulated. However, I share your concern about the loss of surface texture, and would not take this approach in my own house. I've made one window along the lines of what Biff suggested - a d.g. unit, then a vented airspace, then the leaded panel secured in front of that. From the inside the effect should be of a 'normal' leaded window. Unfortunately we haven't had the leaded panel made up yet, so I can't tell you how well this works! The window frame construction took a little bit of thinking out, and there is extra depth overall, but if you were having bespoke windows made this could easily be accomodated.

 

[Penners]

mjl34

Just in case you're not aware of this, Biff is very experienced and knowledgeable on this subject. I should listen to what he says.

 

[biffvernon]

Never heed advice from Penners.

 

[Schoolmarm]

Lol!