problem with damp patch on bedroom wall-just below ceiling level and on inside of chimney flue.The chimney was obvious culprit but had flashing checked & mortar around pot renewed.Also had gas fire type cowl installed.Top courses of chimney,which protrudes full height of house i.e. exterior, suffers from patches of salts.Over the past snowy weeks the exterior brickwork appears wet from the very top down to 4/5 courses below gutter level.Construction is traditional with 2 layers of protruding quarry tiles.I have also checked in the roof to see if water was coming down in side of felt but interior brickwork at ceiling level appears dry.House was constructed 1977.
Any ideas greatly appreciated
You will need to investigate and see if a horizontal dpc has been installed in the chimney at roof flashing level. Since water is getting past the roof level I would suspect this has been missed.
The most economic solution will be to spray the exposed parts of the chimney with a silicone based water repellant.
DIY how to tutorial projects and guides - Did you know we have a DIY Projects section? Well, if no, then we certainly do! Within this area of our site have literally hundreds of how-to guides and tutorials that cover a huge range of home improvement tasks. Each page also comes with pictures and a video to make completing those jobs even easier!