We've just noticed that when closed there is a tiny gap of about 4mm from the aluminium sliding window edge to frame. It's not much but as it gets colder no doubt it will be draughty. The gap wasn't there from the beginning but has only emerged this summer.
They were installed 3 years ago in our new extension. I've been calling the window company but there's been no response. I looked online and the last active trace of them was in Jan 17 - I think they're no longer trading. I looked at FENSA website and it looks as if they want us to claim off an insurance cert but I've filled in their online form and asked them to contact me so we shall we see.
Does anyone know what can be done to remedy the gap? Could they add an extra bit of rubber? Can it be solved?
Advice and help, please.