Fenestration frustrations.

[loughran]

I'm a cabinet maker and there are times when the gap between cabinet maker and joiner is larger than I'd like.

Last year I made new windows for our house, sash and casements and glazed them with double glazed units with... butyl compound. I'm a bit of a traditionalist and would have used linseed putty but the argument for butyl compound seemed pretty convincing. At the time.

6 months and one mild winter later the butyl has failed on most of the windows and water has got into the rebates. Fortunately I made the windows in oak so a bit of damp isn't really a long term problem and as the weather gets better I'll strip the double glazed units out and start again.

But what should I use to bed the units in this time?

I've been doing some work in a house where all the windows have been replaced and the manufacturers have used a dry glazing system. Instead of putty/butyl they've used a black neoprene gasket, 2 or 3mm thick and the casements have drain holes to allow any moisture that gets past the gaskets out.

Now this sounds like quite a good idea (although having drain holes seems a bit like admitting defeat before you've started) and they do look good, so I spent 45 quid on a roll of neoprene gasket ready for the off.

Then this week I've been working on a new build with all new sash windows and the joiners are telling me these glazed units are bedded on U9 glazing silicon. Very neat it looks too.

Does anyone have experience of dry glazing systems or of the glazing silicon ? I'm favouring the silicon method at the moment but it can't be that straight forward can it ? What's special about this U9 silicon and if it's that good, why doesn't everybody just silicon their glass in place ?

Or is the dry glazing (and holes) the way to go ?