Dee Verma
Hi Simon, i have just finished a job just as you describe in Windsor. you will more then likely have to replace the existing window with a new one, but making sure it is fitted correctly. the one i did was a fairly new pvc (plastic) window but badly fitted and it created the same problem you describe. had to be totally removed and the surrounding area prepped correctly and refitted. problem solved. you have a window that has a leak some ware and the recent winds are driving water into and onto the brickwork on the inside wall by means of a capillary action - and this is what is causing you problems. getting damp!