Double Glazed Wooden Sash windows ...

[Chris Bacon]

Is it paint build-up? Is there enough gap at the bead? Often these are nailed on too close to the sliding sash.

Blastation. Seen off again.

[Chris Bacon]

I've never seen rot from 2y. D/G either.

I dunno, it does seem to reduce heat loss... the outside pane does not freeze...

[Stuart Noble]

You can renovate sliding sashes quite easily and cheaply. Re-positioning the staff bead and/or removing excess paint on the sash edges will help them run smoothly, and a few obvious adjustments can eliminate most serious draughts. Because they are usually set into the masonry, they rarely suffer the kind of terminal rot you get on other types of window.

However, they are never going to be draught proof or noise proof by modern standards. Replacing one pane of glass with two doesn't achieve much when draughts are belting round the edge of the sashes, and you would either have to increase the weight of the sash weights (which you may not have room for) or fit those spiral balance things, which are a pain when they seize up.

IMO secondary glazing doesn't work well with sliding sashes. A neighbour of mine has a single pane over each window so that to open the sash window you first have to lift the curtains over the secondary pane and, because there's no room for it to lay flat against the wall, you lose a lot of space in a small room.

[Chris Bacon]

I have done lost of searches looking for a cheap-ish

2y. D/G product. If anyone finds one, please let me know. I think I'll have to make it.

[Chris Bacon]

You haven't seen good stuff, then, and he hasn't got it.

[Timothy Murphy]

You obviously know much more than me about this subject. We have in fact asked expert firms for their advice, and have been told that the only solution is basically to re-make the windows (which seems to be what you specialise in). Several of the windows are slightly rotted. The latest estimate for the work on the windows was 25,000 euro.

There are grants for this work; but in our area the allocation for the year ran out on Jan 1. I'll look into it again. I regard the secondary glazing as a second-best solution; but it is in fact quite successful at keeping the building warm.

[Timothy Murphy]

I think you have misunderstood how our secondary glazing works, at least. The new panes are independent of the old, and there is no increase in the load on the weights.

That sounds like a very simple system. Our secondary glazing can be raised and lowered; there is an upper and lower pane.

[The Natural Philosopher]

It only works if the draughts are fixed.

The aim is in both cases to trap a layer of air in the window area. If the outside window is draughty, it won't trap with a curtain. Secondary glazing will do this if its SEALED.

Best of all is replacement sashes windows, possibly DG, with the curtains as well. That really works. We have new very draughtropoof SG casemets with thick curtains. Its very very warm..