Sash windows need a 3mm gap concerning sash and body to function with no friction stopping clean vacation. With a window that is in excess of painted, twisted, and warped the tolerance may be more like 5mm in spots to allow passage of your sash at “sticky details”. Greig all https://sashwindows75558.blogars.com/34554664/sash-window-draught-proofing-fundamentals-explained