Double glazing existing single glazed sash windows, a good idea? Timmy2017-11-10T13:39:30+00:00If you have sash windows and you live in the UK then you have probably heard about the possibilities of replacing 4mm glass with a slim-line double glazed unit [...] November 17, 2014 By Timmy Uncategorized double glazed sash windows, sash window draught proofing, sash window repairs, sash window repairs london, slimline double glazing 0 Comments Read more...