Can anybody please tell me if those tiny little external vents ( which look like buttons or small one inch long rectangles) which are sometimes fitted to the bottom of UPVC window frames, are really necessary.
I was given some ( in a bag ) with my new "fit yourself" UPVC window and am debating whether they are really necessary. Quite a few professional installations locally are not fitted with them.
I do not wish to drill holes in a lovely UPVC window frame unnecessarily !
Advice welcome please.
I was given some ( in a bag ) with my new "fit yourself" UPVC window and am debating whether they are really necessary. Quite a few professional installations locally are not fitted with them.
I do not wish to drill holes in a lovely UPVC window frame unnecessarily !
Advice welcome please.