Original sealant is heavily discoloured and/or coming away. Which sealant can I use to re-seal on both inside and outside frames? Will Unibond Super all-purpose do the job? Or is there a proprietary sealant specifically designed for sealing double-glazed units? Replacing the units is definitely not an option.
howtomendit.com for free repair help, information and advice.
Try fixfault.com to fix windows and doors.