You are reading a single comment by @bazschmaz and its replies.
Click here to read the full conversation.
bazschmaz-
It means the weights have to be increased but it's a great upgrade in terms of cutting high pitched noise from the street.
I've only done a few because it pushes the price up a lot with extra lead and the more technical glass being expensive. You also can't use a normal putty as it can seep between the panes and discolour the laminate.
Airhead
I think there are diy ways to secure a sash window from inside as long as the glass isn't compromised. I do put laminated glass into renovated sashes which helps a lot with noise but also makes the glass part much less vunerable.