I have a upvc door and when the weather's really hot (like today!) I can't lock it. It's almost like something in the mechanism swells in the heat. Does anyone know what this could be or how I go about fixing it because obviously it's a bit worrying to have to leave my door unlocked in hot weather. Thanks.
Most uPVC doors and windows are built with an aluminium core. Aluminium is one of the metals that expands most when heated. Good luck with the adjustments!