DIY secondary glazing

[shambles]

Sorry - I seem to be spending a lot of time here of late - anyone would think I have nothing else to do...

Does anyone here have any good ideas about self-building or buying secondary glazing? We live in an old house (1800) with lovely georgian cast iron window frames set into wooden surrounds. It would be a crime to remove them in favour of proper double-glazing... But they aren't especially good at keeping the heat in.

I was thinking of getting some lengths of timber maybe an inch and a half square and as long as is needed to screw to the wooden frame around the windows, with a couple of channels routered into them to take some edge-polished sliding glass. Then leave it up all year round, sliding the glass to open the windows. But I'm not convinced it won't swell up and jam if it gets damp, or gather condensation and mould behind it. I'm also not sure how effective it might be. I also thought about internal wooden shutters. But I suspect the cats might object to being kept in the dark whilst we are at work all day.

Has anyone else had any experience of this kind of situation? What did you do?

[Paulh_Boats]

For at least 5 years we have plastic channel from Wickes to hold our secondary panes. It worked ok but the self adhesive eventually dried out so I then had to nail them to the wooden frames with small panel pins. The plastic channel snaps open to remove the panels in summer...snap back in for winter.

I have also thought of routing wood sections for the remaining windows. I would first coat them with 2 or 3 coats of epoxy which will waterproof them very well (modern wooden boats are built with epoxy), then paint or varnish if required. However epoxy breaks down in UV so either the varnish will need re-doing every few years or paint will give a long term finish. You could also use oak strip and finish it with varnish.

You do need an airtight seal and that might be difficult for sliding panes. There maybe a way to add small brass hinges and EPDM rubber as a seal between frame and windows; which would allow the secondary frames to open inwards.

cheers
-Paul

[Ivan]

Not really a direct answer to your question, however, I have professionally-fitted secondary glazing (fitted in the 70s) and it does significantly reduce heatloss. It is not as good as double glazing in this respect, as the separation is quite large - around 8", but it has the extra benefit of being much better at reducing sound - which can be an added benefit. I never get condensation on the secondary-glazed windows, by the way.