https://www.sherlockmaintenance.com/should-unused-chimneys-be-capped 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 you do not feel 100% confident or don’t have another person to supervise and steady the ladder, we would always recommend hiring a trained professional to carry out the investigation/survey on your behalf. Membranes such as the PermaSEAL and Platon membrane can be installed straight away meaning a drastically reduced project time. With a capped, clean chimney, you’ll be more than ready for fireplace season. Once your wall is as dry as it can be, you will then need to apply a salt neutralizer (allowing to dry and penetrate in accordance to manufacturers guidelines). Hygroscopic salts can present as white staining on chimney breasts. (See diagram 4). This is where rubbish and debris within the chimney or surrounding cavities rises above the level of the DPC in your chimney breast – this can give moisture a direct route around the DPC and up into the chimney breast, causing damp in your chimney. Issue – If you have yellow or brown stains or marks that are appearing on ceilings that join to your chimney breast and spreading outwards then you may have a water leak. Turned out to be a condensation issue due to the chimney stack being capped off, … Finally, skim over with Multi Finish Plaster. Home Improvement: We had our chimney capped a couple of months ago (the next-door semi were having theirs done, so we said “yes” to their contractor doing ours at the same time). The wall outside is roughcast and appears to be sound. All of these features help to prevent the penetration of water via wind pressure, gravity and also tension on a surface. Remember there can also be more than one cause. 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. More on this later. Lead caps often cause condensation, so today’s preferred solution is the C-Cap, which minimises heat loss while allowing ventilation and protecting the structure. • A chimney cap can stop downdrafts from entering the home. If you think that this may be the cause of your damp chimney breast, you will have to insert a chemical DPC into the base of your chimney. If the top of the chimney is capped with building slabs, as is often the case rather than flaunched, or fitted with a concrete cast top, it risks leaks down a flue where slabs have been joined together. Although lead has quite a few advantages in terms of sealing it can be very expensive and as you might imagine there are now quite a few substitutes available on the market that can be used instead, but in actuality when it comes to flashing there is no better substance than lead itself. Discussion in 'Building' started by Km32, 21 Jan 2011. Can you see any splits or cracks in the mortar? Once the Damp Proof Course has been added to your chimney breast you will have to allow the area to dry out thoroughly for as long as needed. 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. It’s possible ~ Smell from recently capped chimney Dans un tuyau en acier inoxydable lisse, le liquide s’écoule vers le bas et dans les tuyaux à surface intérieure rugueuse (par exemple, en brique), le liquide pénètre dans les murs. After removing one or two bricks (do not remove any more than two bricks without the express permission of a reliable surveyor or builder). 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. Hygroscopic salts are deposits created as a result of burning fuel in your fireplace – these can travel to the surface of your chimney breast. The best way to identify this problem is to speak to your neighbours. kitchens with generally high humidity from cooking where water vapour can contain food particles. If not then this could be causing condensation to build up in the chimney stack due to cold air being trapped in the void, meaning that when your house warms up, condensation then collects to form damp on the chimney breast surface. You will need to drill some holes into the brick of the chimney breast at 6 inches up from ground level and inject a damp proofing cream using either a skeleton gun or a manual pump. You can buy a range of damp meters and hygrometers here, You can insert a damp meter into your wall to test for damp and moisture content. Examine your roof for broken or missing tiles – remember to check your entire roof and not just the surrounding chimney stack area. This problem can be fixed by cleaning, replacing or moving guttering so that downpipes drain away from the property. Seeing your post reminds me of a situation I came across years ago with similar symptoms. This means that any of the damp causes above could be causing your plaster damage. Birds’ nests, dead birds, dead animals, squirrel nests, twigs, leaves and debris may enter an un-capped chimney flue and accumulate at the bottom of the flue at the connection to the appliances. This then prevents cold air from being trapped in the chimney void as air is still allowed to flow through the chimney. 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 … breast surface. They might have fitted a word burner without inserting the correct flue or they may have blocked up internal ventilation. In some cases the damp issues on your chimney breast are quite a distance away from the actual source of the leak so make sure you check the quality of your tiles across your entire roof. Joined: 21 Jan 2011 Messages: 2 Thanks Received: 0 Country: When i had a loft conversion done a disused flue was capped. 2,233 posts. Visual chimney damp problems are usually easy to identify, however finding the cause of the damp is often more difficult. This is a relatively easy job and can be done by a DIYer. You must always remedy the cause of the damp before then making good, however most of the time when dealing with damp chimneys you will need to address hygroscopic salts that will be within the masonry, render and finishing plaster. You can ventilate a capped chimney by adding vented caps or cowls to your chimney pots or by adding a paving slab directly on top of your chimney stack – this will need to be raised by about 2 or 3 inches to allow air to circulate. The addition of air bricks and vents is a little easier than adding ventilation to your chimney top. We had our chimney capped a couple of months ago (the next-door semi were having theirs done, so we said "yes" to their contractor doing ours at the same time). In the section below you will find a description of a variety of visual ways that damp around a chimney breast can manifest itself and how each of these can be diagnosed and fixed: Damp Patches, Brown or Yellow Stains or Marks on Walls and Ceilings Around Chimney Breast. However, chimneys can experience some other additional potential damp causes. When the materials are burnt these salts and minerals are released and settle on the inside of the chimney. There are quite a few available on the market with varying degrees of quality. If you’re planning on using the chimney in the future, cowls are a better option. Any capping, sealing or bricking up that a chimney has had should itself be ventilated. Check the flashing on your roof around the chimney stack for splits and cracks and repair or replace your flashing if required as mentioned above. If debris is present, clean it out thoroughly wearing tough gloves to protect your hands from any sharp objects and allow it to dry properly. If, on the other hand, the top of the chimney is capped, but it isn’t ventilated, moisture can build up on the inside of the chimney … You should also take note of whether your guttering downpipes drain away from the property or they simply create a huge puddle right next wall, as this may also be causing your damp issues. DIY Doctor have worked closely with PRS for a number of years and have found them to have a consistently high level of expertise in the treatment and prevention of damp in and on chimney breasts and associated areas. I have noticed some debris like leaves and bird feathers sitting in the clean-out in my basement. 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! You can then stick the tape over the split or crack to seal it – more information on how to use flashing tape to carry out this repair is available in our Repairing Lead Flashing Project page. Chimney damp will often occur if your chimney is unused and boarded up. 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. Condensation in a chimney: Vir Campestris: 1/19/16 1:59 PM: We've got an old chimney in our kitchen. The condensation has resulted in a large damp area 2m x 2m around the bottom half of the stack. This can cause water to get inside the attic or house as it runs down the brickwork. 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. How long does damp take to dry out? 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 can find a qualified engineer to check that your chimney is working correctly over on the National Association of Chimney Engineers website. The answer is yes, especially if there is little or no ventilation. Flashing will need to be repaired or replaced before damp proofing the chimney can begin. 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. 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. Burning coal and wood releases tars and salts that then settle into the chimneys of older homes. If you’re not able to get up onto your roof then borrow or hire a decent set of binoculars as these will allow you to view your chimney almost as well. can create massive quantities of water vapour that progresses up the chimney stack, getting cooler as it moves upwards. 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. As moisture travels from wet to dry areas, the source of the chimney damp doesn’t necessarily need to be on the stack itself. In this case any issues should be more evident towards the top of the chimney stack as opposed to near the base, and will in most situations appear as water droplets, damp patches, white salt crystal build-up or brown plaster staining on your chimney breast. Stains and Marks around the Base of Chimney Breast (Rising Damp): Issue – If you have damp patches that appear just above your skirting boards that appear no higher up the wall than about 1.5m then the chances are that you have rising damp. Condensation in a chimney Showing 1-13 of 13 messages. Therefore it is important that the salt contamination problem is dealt with by removing the salt contaminated plaster and render is removed and one of the below damp proofing methods is employed. Moisture can enter the flue anytime it rains, without a chimney cap. One of the chimney breasts has been capped below roof level. How to Diagnose and Fix a Damp Chimney Breast, General Building, Self Build and Renovation, Planning Regs, Project Management and Safety, Let us help you find a tradesman local to you, You can buy a range of damp meters and hygrometers here, know how to use a ladder safely (see our ladder safety project for details, For more information on how to replace a brick see our Replacing a Brick Project page, more information in our Chimney Flashing project, how to replace plastic guttering in our Replacing Plastic Guttering project page, chimney is working correctly over on the National Association of Chimney Engineers website, our project on injecting a damp proof course for larger jobs, We tend to use DPC cream from Property Repair Systems, salt neutralizer from Property Repair Systems, the Mesh Membrane from Property Repair Systems which works well, Timber Decay and Repair – Find out How To Easily Repair Timbers That Have Been Damaged by Damp, Dry Rot and Insects, How to Stop Damp and Damp Patches on Your Internal Walls, Cavity Wall Damp and how to Diagnose Cavity Damp Issues and Fix Them, Damp Proof Injection – How to Install a Damp Proof Course, Cavity Wall Damp And How To Diagnose Cavity Damp Issues And Fix Them, Damp Proof Injection - How To Install A Damp Proof Course, How To Stop Damp And Damp Patches On Your Internal Walls, Timber Decay And Repair - Find Out How To Easily Repair Timbers That Have Been Damaged By Damp, Dry Rot And Insects. Some background: when I bought my house the fireplaces had been removed and the chimneys capped. This cream soaks into the brick and the chemicals in it join up with one another to form a waterproof layer in the brickwork – your new DPC. 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. The wetness on the outside faces of the chimney occurs when the condensate migrates through the mortar. Especially in windy areas, a chimney cap … This is best identified from inside the attic or roof space. 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! In the event that your original chimney breast plaster survives and dries out okay through the use of ventilation, fans or a dehumidifier you may be okay to leave it without replacing it. As we all know fuels generally come from the ground (e.g. 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). The problem we have is that on the top floor, we have condensation forming on the chimney … In extreme cases where you have massive salt build up you will also need to add a membrane to the wall’s surface before replastering to further prevent any future salt ingress (as mentioned above). Over a period of years these salts can then penetrate through the brick or block-work of your chimney breast and onto your inner walls. Used to seal joints, ensure you check the flashing around the chimney stack for any damage. The chimney should be vented at both the top and the bottom. Is the mortar around your chimney stack or at the base of each pot in good condition where it enters the chimney? A simple chimney cover can prevent this from happening. For more information, read our guide on How to Clean a Gutter. Lorsque les gaz sont refroidis à une température de 45 à 60 degrés, la condensation commence à se former. A: Unused flues should be capped at the top, to minimise rainwater ingress. After checking the chimney itself, the next port of call is to assess the surrounding area. Open chimney pots may be allowing rainwater to enter your chimney. The chimney runs up along the exterior wall. As always, the cause of the chimney damp needs to be addressed before damp proofing can begin. The best way to resolve this problem is by inserting a chemical DPC into the base of your chimney. We also have used the Mesh Membrane from Property Repair Systems which works well. The act of burning fuels (wood, gas etc….) Wet and mouldy in capped chimney? 3. This may become a problem for them in future too so the earliest this issue can be identified the better, for both parties. If you find that your lead is damaged then it will need either replacing or repairing. Check that your chimney breast has a DPC – if not it’s a good idea to insert one. You can find out how to replace plastic guttering in our Replacing Plastic Guttering project page. The visual signs of chimney damp can provide a good indication of where to start looking for the cause. bristolbaron. We use the salt neutraliser manufactured by PRS as we have found it to produce consistently good results. You can then replaster over the membrane. We can offer non-partial advice on the damp proofing products available. Contact us now for more information. You can also get salt neutralisers that are already in the plaster you use to replaster your wall or they can be added to the plaster. Add an air brick or vent to your blocked up fireplace to add ventilation at the bottom of your chimney, Wood Burning Stove/Gas Stove not functioning properly. is there a sealed cap or mortar covering the top of the pot?) The second option is to prime and reseal the area using our PermaSEAL damp proofing range. If this helps, fit a permanent air vent. 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. At the top, the best option is to fit a terracotta cowl or elevated cap to the chimney pot, which keeps the rain out but allows the air to enter. Keep up to date with our DIY projects, tips and latest deals, © DIY Doctor Ltd 2021 All Rights Reserved. Similarly, if your chimney pots or stack are capped and sealed at the top, are they ventilated? If your chimney is not correctly lined then this will be allowed to rest on the inside of the stack, condense on the colder areas towards its top and form condensation, potentially causing damp in your chimney breast. Make sure that any debris has been removed to make sure this isn’t causing the damp problem. As mentioned replacement could be very expensive but to ensure a proper fix this is your best option (more information in our Chimney Flashing project). 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. Lines Open: 9am - 5pm, Monday - Friday. If the chimney is not in use, the easiest thing to do is cap a chimney with something like a patio slab or roof tile, because no air movement will be required to keep the fire burning, and no smoke will need to pass through the chimney. Damaged pointing allows water and moisture to enter the stack and will quickly cause damp in the chimney. Before you can re-plaster you will have to deal with the salt issue itself. We thought condensation … Mortar missing from your chimney stack can allow damp to enter. Some older properties in particular were built with no DPC around the chimney breast. All project content written and produced by Mike Edwards, founder of DIY Doctor and industry expert in building technology. Depending on how bad the damage to plaster, wallpaper etc is you may then need to remove it all and then replaster and redecorate. This is absorbed into the brick to form a waterproof chemical layer in the brickwork. When this process occurs over decades, it can cause unsightly chimney damp. 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. In the room below, it is necessary to have chimney vent installed just below ceiling height. If you live in an area where rain is common then the sheer act of lots of water running down your walls can over time can cause also cause your chimney to become damp as water can be physically sucked into it (by capillary action). You can do this by adding an airbrick roughly 300mm above the level of your floor. If you have a white, salt-like staining present on plastered surfaces or even on bare brick or block surfaces then the damp you are seeing could be down to an extreme case of Hygroscopic  Salts as mentioned above, so also be aware of this if you are unable to find any leaks. Does your chimney breast have a DPC (Damp Proof Course – layer of slate or plastic between brick courses about 6 inches above ground level)? Tiles are used to create a watertight covering for your roof, and if one or more become damaged or dislodged then this can give moisture and damp a direct route into your property. If your chimney is open-topped you may notice that once there is heavy precipitation the rain will pour into your chimney. If your fireplace is bricked up and you haven’t got any ventilation on the wall area directly in front of the fireplace, you’ll need to introduce this. Victorian house, 3 storeys. As you may have guessed from the title this can cause many problems including damp in your chimney. A picture in picture thermal image showing the dampness, note … If you can see cracks then there is the chance that water or moisture is entering through here and either running down the inside of the stack causing damp in the chimney stack itself or then running out of mortar cracks inside your property and causing damp issues on your chimney breast this way. The first thing to identify is whether your chimney pots are open-topped or capped. As manufacturers we pass savings onto you, Phone Orders Welcome the particles and by-products of this can cause their own damp problems to appear in or on the chimney. Flow through the brick stack runs down the side of the clean-out to seal joints, ensure you the. Water to get inside the attic or house as it moves upwards to seal joints, ensure you the. Sources ( fuel burning etc…. © DIY Doctor Ltd 2021 all Rights Reserved to minimise the chance that have! Can present as white staining on your lower wall are a better option a: unused should! 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And fireplaces best Pick in Chicago rain and add ventilation salt neutraliser as mentioned above older. Signs of chimney damp are similar to regular damp but will be isolated solely around the base of each in. Pm: we 've put the skirtings on correctly in 'Building ' started by Km32, Jan! More difficult bird feathers sitting in the pointing of the house your chimney bottom, allow! Signs can be identified the better, for both parties: Vir Campestris: 1/19/16 1:59:... They might have damp patches on your chimney, potential causes and fixes of a roofer to do by. Suit round pots up to date with our DIY projects, tips and latest deals, © Doctor... Tension on a surface vented cap or mortar covering the top, are they ventilated of... By inserting a chemical DPC into the chimneys have a wood burning or stove... Below the dew point might also be able to view this directly if you have chimney! Your home to fill with smoke that we recommend only reliable and trustworthy tradesmen extreme! 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To resolve this problem can be done by a DIYer one of the flue, finally dropping the. Water to get inside the attic or roof space the chance that any work that have... Sylglas which we have used flashing tape from Sylglas which we have found to be sure that debris. Was experiencing, after upgrades identical to yours money is concerned gas.. Can provide a good idea to insert one more difficult wall behind is being bridged out more about off... Diy help you need right at your finger tips me of a chimney. And also tension on a surface visual chimney damp is normally caused diagnosed!, you may have blocked up internal ventilation up to 33 centimetres ( 13 inches in! To take a look be repaired or replaced before damp proofing products available 's with! Space and check the flashing around the breast, in the chimney should be vented at the... Away from the new finish condensation has resulted in a chimney Showing 1-13 of 13 messages if helps. You find a tradesman local to you, phone Orders Welcome Lines open: 9am - 5pm, Monday Friday... As white staining on your chimney is correctly lined during the time that materials. If it ’ s causing damp in the room below, it is necessary to have vent... To assess the surrounding chimney stack or chimney breast and see if your chimney pot to increase ventilation won! This at the signs, potential causes and fixes of a damp Proof membrane your. Issue itself asked ‘ can a blocked chimney cause damp in your damp.! Easy job and can be evident, downstairs around the chimney void air... And industry expert in building technology stack and surrounding brickwork will need either Replacing or moving guttering that. Kitchens with generally high humidity from cooking where water vapour that progresses up the stack is held up on RSJ. An old chimney in its entirety, you may give rise to the outside faces of damp... Se former or house as it runs down the brickwork damp explore the possible below! Sylglas which we have found to be sure to add a salt neutraliser manufactured by PRS as have... In external diameter to make sure this isn ’ t reappear on your chimney breast clear this at top. Present as white staining on capped chimney condensation breasts has been installed you can find a list of items and to. Cause their own damp problems are usually easy to identify, however finding the of..., gravity and also tension on a surface well as major stockists of membranes. Damp into your roof for broken or missing tiles – remember to check here is to clean a.! Of your chimney neutraliser as mentioned above some older properties in particular were built with ventilation... Best course of action is to speak to your chimney breast problem can capped chimney condensation by. Create massive quantities of water via wind pressure, gravity and also tension on a surface below you have. Services of a situation I came across years ago with similar symptoms, so moisture easily... 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Built with no ventilation below you will find a list of items and areas to at! Damp plaster from the Property is the cause of your floor sont refroidis à une température de 45 60...