If you have stains and damp marks around the base of the chimney breast, no more than 1.5m high and salt tidemark, then this could suggest rising damp caused by a bridged damp proof course (DPC) or lack of DPC. The wetness on the outside faces of the chimney occurs when the condensate migrates through the mortar. Apply a mesh membrane to your wall to be sure that salts won’t reappear on your wall. However, chimneys can experience some other additional potential damp causes. Fix – If you have found that you do not in fact have a Damp Proof Course in your chimney breast then it is a good idea to add one. Burning coal and wood releases tars and salts that then settle into the chimneys of older homes. Other visual signs can be a damp chimney breast and ceiling, damp walls either side of your chimney breast, damp in your loft or attic space around the chimney area or even damp halfway up a chimney breast. Another cause of your chimney damp could potentially be a bridged DPC in your chimney breast. The addition of air bricks and vents is a little easier than adding ventilation to your chimney top. As we all know fuels generally come from the ground (e.g. Brown stains on your lower wall are a sign of rising damp. It’s a good idea to firstly establish that you have a damp problem at all, and this can be done in two ways: For a reasonably accurate measurement of the moisture content in your chimney breast you can use what’s called a "Damp Meter". With more than 28 years’ of experience in the damp proofing industry, we have the expert knowledge that you need to help you get the job done. The salts themselves are hygroscopic (moisture attracting) and when present on your chimney area they attract the moisture within a room space and can create damp patches on your chimney breast. There are quite a few available on the market with varying degrees of quality. Again, the way to remedy this is to replace your caps with either a chimney cowl on each of your chimney pots or a raised paving slab directly on top of your chimney stack. Even if this is not the root cause of your issue, it’s certainly not helping so will need repointing to prevent future problems. You must have JavaScript enabled in your browser to utilize the functionality of this website. A picture in picture thermal image showing the dampness, note … Our two most popular solutions are below. The fireplace in a townhome we recently purchased is not useable,and making it u to code is beyond our finances. To avoid animals coming down the shoot and a drafty home, we wereadvised to cap the chimney.  After removingdebris, the chimney was caped, but we now have a musty odor in our living room.The shoot was checked again, and seems clean, so it was capped … You should also check whether inside your roof space you can see any day light coming in around the stack – this is where the lead has failed. There are quite a few DIY chemical DPC kits available today that can be quite cheap and easily to install by anyone with a bit of DIY knowledge There are quite a few products of this type on the market, one we tend to use is mentioned above. Damaged pointing allows water and moisture to enter the stack and will quickly cause damp in the chimney. The best way to check that this is the problem is to remove a brick from the base of the chimney breast and access the inside to see if there is moisture present. A damp chimney breast problem can present itself in a number of different ways and for a number of different reasons. If your chimney is open-topped you may notice that once there is heavy precipitation the rain will pour into your chimney. get some images of inside the breast. Does your chimney breast have a DPC (Damp Proof Course – layer of slate or plastic between brick courses about 6 inches above ground level)? Most of the internal walls of a house are plastered and once damp and moisture have been allowed to sit on or penetrate into a plastered surface for a period of time (including plasterboard), that surface will never be the same again. The MARCONE chimney pot can be useful to increase a chimneys height and help to counter down draught. We also explain what products can then be used to ensure that no damp issues return in the future and your chimney repair job is a complete success! You can then replaster over the membrane. How to seal a chimney. You should also access your loft space and check the chimney breast and see if it’s damp. Fix – Once you have resolved the cause of the damp (and either fixed the leak source or established that it’s down to a salt issue) remove all the damaged plaster from the chimney area and any affected surrounding areas (if any) and allow to dry thoroughly for as long as needed. Also be aware that just because there is no evidence of a leak around the immediate chimney area, water or moisture may be getting in and running along to the chimney area to form damp so ensure that your checks are thorough! JavaScript seems to be disabled in your browser. In order to thoroughly check your chimney and building to find the root cause of the problem, this may involve the use of a ladder. I did this last summer in my own home and it stopped some leakage I was experiencing, after upgrades identical to yours. This has led to condensation. A chimney cap had been added to the chimney above the furnace flue when the roofing had been done to complement the existing cap above the fireplace flue. Condensation can occur when ascending combustion gases meet cooler temperatures in higher parts of the flue, finally dropping below the dew point. Joined: 21 Jan 2011 Messages: 2 Thanks Received: 0 Country: When i had a loft conversion done a disused flue was capped. However, condensation in your chimney could also be caused by a blockage. The second option is to prime and reseal the area using our PermaSEAL damp proofing range. The problem we have is that on the top floor, we have condensation forming on the chimney … Seeing your post reminds me of a situation I came across years ago with similar symptoms. Decent ventilation, fans and a dehumidifier will help. 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