Roofing

Leak where extension (flat roof) joins original house

Anonymous user 09/03/2024 - 2.58 PM

We have a 1 year old extension with a flat roof. We have had leaks for c. 3 months around the corner where the extension joins the old part of the house (now supported by an RSJ) and the wall that we share with our neighbour (terraced). The flat roof was felted (I think), and we have had it covered with fibreglass paint, an obvious hole (by the edge of the felt/air vents) sealed with tar-type paint, and all the roof-lights resealed. However when it rains heavily we have water actively dripping through. Can anyone suggest what might be needed? Does the hole that was 'sealed' need fully overlaying? Is it normal to have air vents where a new flat roof meets an old house? Could it be coming through from nextdoor's internal draining pipes/plumbing? Is there a way of finding out?! Thanks for your help!