We know that tackling the problem of chimney damp can be tricky. As you may have guessed from the title this can cause many problems including damp in your chimney. The chimney should be vented at both the top and the bottom. Membranes such as the PermaSEAL and Platon membrane can be installed straight away meaning a drastically reduced project time. You should also check inside your roof for any signs of water leakage or a build-up of a white salt-like substance (hygroscopic salts) as this could indicate flashing failure. For a cheaper option, you can instead remove your pots and add a paving slab on top of the stack instead, raising it up on all sides by about 2-3 inches to provide ventilation. Permagard is a leading manufacturer and supplier of basement waterproofing products, damp proofing membranes, and structural repair products. When the materials are burnt these salts and minerals are released and settle on the inside of the chimney. To do this you will need to remove a brick or bricks from the chimney breast or bricked up fireplace and insert an air brick in its place to increase ventilation within the chimney void (a link to our Removing a brick project can be found above) This should help minimise any damp in your chimney breast that has been caused by poor ventilation. The act of burning fuels (wood, gas etc….) Another typical indicator of hygroscopic salt contamination is the fact that the damp patches will in most cases be more apparent during wet weather or more humid conditions. You can do this by drilling holes into your chimney breast about six inches up from ground level and injecting a chemical cream DPC into the holes. 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. Depending on how bad the damage to plaster, wallpaper etc is you may then need to remove it all and then replaster and redecorate. Once you have added the salt neutralizer (and membrane if required) and allowed it to dry (following manufacturers guidelines) you can then go ahead and plaster and redecorate your chimney area. With a capped, clean chimney, you’ll be more than ready for fireplace season. If there are any white salt deposits present, be sure to add a salt neutraliser as mentioned above. As always, the cause of the chimney damp needs to be addressed before damp proofing can begin. If water is entering your chimney pots this way, simply add some chimney cowls to your chimney pots – these stop the rainwater ingress whilst allowing ventilation. Home > DIY How To Projects and Tutorial Guides > How to Diagnose and Fix a Damp Chimney Breast, This project is sponsored by Property Repair Systems. Even if this is not the root cause of your issue, it’s certainly not helping so will need repointing to prevent future problems. One of the chimney breasts has been capped below roof level. To check whether this is occurring you will need to remove one or two bricks and access the chimney breast to have a look inside it for any debris – do not remove more than two bricks without consulting a reliable tradesman or property surveyor. 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. Ventilation in the form of air bricks should also be fitted into the brickwork near the top of the stack to stop internal condensation. I have noticed some debris like leaves and bird feathers sitting in the clean-out in my basement. There are a few options when damp proofing a chimney, all options require the removal of the render back to the exposed brick chimney breast. The visual signs of chimney damp can provide a good indication of where to start looking for the cause. Allow the wall to dry out thoroughly, giving it as much time as is required, in some case this can be several months. The best way to identify this problem is to speak to your neighbours. Discussion. If they are open-topped and your chimney is not in use there is the chance that moisture is entering through here and travelling to the base of your stack, causing damp in your chimney. The answer is yes, especially if there is little or no ventilation. Condensation in a chimney Showing 1-13 of 13 messages. 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 … Wetness around a chimney to be due to the condensation of the airborne moisture in the exhaust gases discharged by the furnace on the cold chimney walls. This is a relatively easy job and can be done by a DIYer. is there a sealed cap or mortar covering the top of the pot?) If your chimney is not sufficiently capped, this can allow rain to pour straight through the top of the chimney resulting in a significant leakage. This problem can be fixed by cleaning, replacing or moving guttering so that downpipes drain away from the property. The wetness on the outside faces of the chimney occurs when the condensate migrates through the mortar. While we strive to provide relevant information to all homeowners, some of the material we publish may not pertain to every area. You may need the services of a roofer to do this. https://www.permagard.co.uk/media/blog/main_image/Damp-Chimney-Breast-MAIN.png, https://www.permagard.co.uk/skin/frontend/permagard/default/images/permagard/logo.png, Microshield Ultra 5L - Masonry Waterproofing Cream, Kiesol C DPC Injection Cream 10 X 310ml Kit, The complete guide to wall tanking & waterproofing, Green Roof Maintenance - A Complete Guide, Permagard to Reopen Online Store & Offer Click and Collect, Temporary Closure due to Coronavirus: The Right Decision In Difficult Times, Damp patches that come and go as the weather changes. If you have a wood burning or gas stove in use you have to ensure that the chimney is correctly lined. Some older properties in particular were built with no DPC around the chimney breast. Joined: 21 Jan 2011 Messages: 2 Thanks Received: 0 Country: When i had a loft conversion done a disused flue was capped. If you can’t find the information that you need to help find the cause or fix your damp problem, we are more than happy to discuss your issues and find a solution so you can enjoy a damp-free home. Remove all the damp plaster from the affected chimney area and any surrounding areas and take it right back to the bare wall behind. The meter itself usually features two little prongs on its base and you stick the prongs into the damp area and on the face of the meter it will show a percentage of damp content in that area. If your chimney is blocked up and is capped and sealed at the top, the lack of ventilation could be causing chimney condensation to build up in the void, meaning that when your house warms up, condensation collects and forms damp on the chimney breast surface. You may be thinking that some of the chimney’s features are going to be hard to see without physically climbing onto your roof and you would be right! If any of these symptoms are visible then simply removing them can stop the issue in its track then its a case of making good the effected areas. During the build process or over time, rubbish and debris can collect in the base of the chimney stack or in adjacent cavities and any moisture or water that descends down can seep up through the rubbish, allowing it to travel around the DPC and back up into the wall creating the damp in your chimney breast. (See diagram 4). … If you find that your lead is damaged then it will need either replacing or repairing. 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. As mentioned above some older chimney breasts do not have a Damp Proof Course installed. There are large patches of damp to the right of the chimney in the 1st and 2nd floor rooms which I assume is caused by condensation. (i.e. Decent ventilation, fans and a dehumidifier will help. There may be no issue with the flue and the cause may be poor ventilation up the chimney stack itself, but do not chance it – get it inspected now. If your chimney is blocked up and is capped and sealed at the top, the lack of ventilation could be causing chimney condensation to build up in the void, meaning that when your house warms up, condensation collects and forms damp on the chimney breast surface. If you share a chimney with your neighbour it is possible that recent home renovations, such as the installation of a wood burner may be causing damp in your home due to poor chimney flue installation or inadequate ventilation. We use the salt neutraliser manufactured by PRS as we have found it to produce consistently good results. 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! Also confirm that water is not being allowed to access through the stack or pots. This can cause water to get inside the attic or house as it runs down the brickwork. 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. For more information one this have a look at our project on injecting a damp proof course for larger jobs and also our project on smaller chemical DPC jobs. This can lead to the home owner to think the issue has not been resolved. A poorly ventilated sealed chimney can cause new chimney damp issues in the form of condensation build up or in some cases make existing damp issues worse. Signs include: These signs can be evident, downstairs around the breast, in the above room and the attic. Km32. You can then replaster over the membrane. The lead flashing used on your roof is effectively there to seal any joints around the roof where it meets a wall or a chimney stack. 3. We are official distribution partners for Remmers as well as major stockists of Newton Membranes. If the origin of the issue is not completely fixed then any repairs will be short lived, wasting the time that it has taken to patch up the damage and also any funds spent, as a few months later you will just have to do it all over again. Fix – There are several ways to remedy this problem with varying degrees of difficulty. Hygroscopic salts are deposits created as a result of burning fuel in your fireplace – these can travel to the surface of your chimney breast. Remember there can also be more than one cause. However, chimneys can experience some other additional potential damp causes. Grab your copy now for all the DIY help you need right at your finger tips! Chimneys on older properties have been exposed to the weather for a long time. If they are open-topped and your chimney is not in use it’s possible that rain or moisture is entering through the opening and causing damp in your chimney. Have a good look inside your roof for possible leaks. Any capping, sealing or bricking up that a chimney has had should itself be ventilated. When a chimney is capped and blocked up or an internal fireplace is bricked up this then removes some of the original ventilation, and if this is not compensated for then this can create condensation and then damp issues within the chimney stack or on the face of the chimney stack e.g. Strip back your plaster to the wall – you can then either add your salt neutraliser directly to the wall or add it to your replastering plaster – you can also get plaster mixes with a salt neutraliser already added. Ventilating your chimney top can be a little tricky as it will involve you climbing onto your roof and fixing the vented cap, cowl or slab to the chimney stack. If after examining the damp in your chimney area following the guidelines above you are still unsure about the cause of the damp and how to fix it give Property Repair Systems a call on 01626 872 650. If the cause is leakage, once dried out correctly you can replaster and then redecorate, but if the damp was caused by hygroscopic salts or you had ‘salt’ deposits present then you will need to first add salt neutralizer to the wall’s surface to prevent any further salts penetrating through. In the case that you have debris and rubbish in the chimney breast void the only choice is to clean it out. A damp chimney breast problem can present itself in a number of different ways and for a number of different reasons. 2,233 posts. Inspect your guttering for any splits or cracks, poor joints on any down pipes or broken brackets (sections of guttering can sag and cause joints to fail when you have broken or faulty brackets). If rising damp is determined as your problem, you will only need to remove the render up to 1m minimum or 300mm above the last sign of damp. Broken roof tiles can allow damp into your roof timbers, Ventilation (capped or sealed chimneys and bricked up fireplaces). They might have fitted a word burner without inserting the correct flue or they may have blocked up internal ventilation. Brown stains on your lower wall are a sign of rising damp. This can lead to a degradation of the brickwork and also the mortar joints often making them more absorbent or even cracked leading to water ingress to the chimney leading to damp getting in and possibly tracking to internal surfaces. Check that your chimney flashing is in good condition. Seeing your post reminds me of a situation I came across years ago with similar symptoms. A picture in picture thermal image showing the dampness, note … To find out more about closing off or blocking up a fireplace, have a look at this project. This may become a problem for them in future too so the earliest this issue can be identified the better, for both parties. Use a salt neutraliser to stop salts from appearing in your wall. Downdrafts can cause your home to fill with smoke. The moisture can damage your walls and ceiling. This can cause a potentially fatal amount of Carbon Monoxide to build up, so please take precautions to minimise the level of fumes present in your living space. Damp chimney breast issues are normally caused, diagnosed and fixed in a similar manner to ordinary damp issues, but with a few subtle differences and potential causes. As manufacturers we pass savings onto you, Phone Orders Welcome Broken or blocked gutters allow water to collect in unwanted areas and enter through any cracks in the mortar causing numerous damp and structural problems throughout the home, including chimney damp. There are several different potential causes of this the first being that you may not have a DPC (damp proof course) installed into your chimney breast. Burning coal and wood releases tars and salts that then settle into the chimneys of older homes. In the event that they have carried out some work on the chimney and it looks like this may be the cause of your damp issues you will have to come to an agreement on how it is fixed. coal, wood etc….). This means that any of the damp causes above could be causing your plaster damage. Any defective tiles will need to be replaced to ensure that your home is protected from the elements. Condensation in a chimney: Vir Campestris: 1/19/16 1:59 PM: We've got an old chimney in our kitchen. Add a vented cap or cowl to your chimney pot to increase ventilation. You can ventilate a blocked up fireplace by adding an airbrick or vent to the wall in front of the fireplace – this can be added to the wall about 300mm up from floor level or you can add it below your floor if there is an underfloor space to minimise draughts in your living area. Another issue could be that the DPC is being bridged. You've just added of the product to your cart. If it is, then this could be damaged pointing that needs repairing or possibly even open chimney pots that could do with a chimney cowl being added to prevent the rain from entering whilst allowing ventilation. The ventilation for a blocked up fireplace can usually be found on the wall in front of the fireplace itself at ground level somewhere around 300mm up from the floor (occasionally in properties with an under-floor void, the vent will be under the floor as this helps to reduce draughts). The membrane then acts as a barrier preventing any further salts from penetrating through. Discussion in 'Building' started by Km32, 21 Jan 2011. If you don’t have a DPC around your chimney breast and water and moisture gets inside the stack and is allowed to sit at the base, or the ground beneath your chimney breast is damp, then this damp can rise up into the walls of your chimney breast (rising damp). Mortar missing from your chimney stack can allow damp to enter. 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