Ronniecabers.... Hey, I'm no expert in this.
I'm only relaying the reasons I was told and why they were replaced, there's no need to reply with such a comment .... could you have just said, you must be mistaken.
After many inspections, one from a FENSA surveyor, two separated inspections by the local council surveyors, who said, whenever old window or door frame/unit needs replacing, under Building Regs, has to be replaced with double glaze units.
The Housing Association were arguing otherwise and I was stuck in the middle.
I was happy with the old and the new single glazed wooden doors, they never caused a constant draught and never needed adjustment
I'm not a builder or window fitter, hence why I turn to a forum such as this.
These uPVC french doors have been bane of my life.
3 complete uPVC french doors units been fitted since 2010, the current have been fitted since 2020 and non have provided a draught proof seal
The french doors are to what's called a Juliet balcony, to my living room and my flat is on the second floor.