On 17/09/2011 22:14, naffer wrote:
Just about to have some new plastic DG fitted. Total fit around large
house.

The guy from the company noticed that some of our DG windows (all of
softwood, 'cos that's why we're replacing) said, "Where you have
trickle vents already fitted, we'll have to do the same".

We had an extension added about 12 years ago and the DG on wood frames
in that part of the house all have trickle vents. The rest of the
house has older DG on wood, done 25+ years ago without trickles.

I *think* the regs about having trickle vents would have come in between
12 and 25 years ago?

There's a basic rule that when replacing windows you can't 'downgrade'
them (in terms of compliance with regulations); so if trickle vents are
in place in the old windows, you can't replace them with new windows
without the vents.

David