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. As always, the cause of the chimney damp needs to be addressed before damp proofing can begin. (See diagram 4). Condensation in a chimney Showing 1-13 of 13 messages. 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. 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. 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. All project content written and produced by Mike Edwards, founder of DIY Doctor and industry expert in building technology. If you have a DPC, then check the area for anything that could be bridging the DPC for example renders/ finishes possibly debris in cavity walls. Wet and mouldy in capped chimney? 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. Grab your copy now for all the DIY help you need right at your finger tips! If you have a broken gutter, in heavy downpours water can run down the face of a wall and seep into any splits or cracks in mortar, presenting as damp in your chimney breast. 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! Any capping, sealing or bricking up that a chimney has had should itself be ventilated. Is the mortar around your chimney stack or at the base of each pot in good condition where it enters the chimney? There is an irregular water mark stretching either side of my chimney breast on the ground floor - its definatley not rising damp as it only appears midway up the wall (about 30 cm from the ground) - we've had the place professionally dampcoursed, as did the people before us. The problem we have is that on the top floor, we have condensation forming on the chimney … Hygroscopic salts can present as white staining on chimney breasts. Once dry you can then redecorate again but beware this may be a short lived fix. 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. … 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. 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. Once all is dry and treated you can now go ahead and replaster your chimney area and redecorate as required. Applying a DPM directly over the area isolates the salty background from the new finish. Remember – if you don’t allow for adequate ventilation you will most likely suffer from condensation in the chimney shaft and possible damp patches on the wall. Let us help you find a tradesman local to you, We look at what’s causing damp in your chimney. It is not unusual for older properties to be built without a chimney DPC, we've even seen new or replacement chimney harths installed without a DPC below it leading to rising damp. You can then replaster over the membrane. 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. 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. NOTE: Burning fuels produces fumes that can be potentially fatal if not removed from the property correctly or if there insufficient air within a room space. 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. For more information on how to replace a brick see our Replacing a Brick Project page. 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. Mortar missing from your chimney stack can allow damp to enter. We also have used the Mesh Membrane from Property Repair Systems which works well. Even if this is not the root cause of your issue, it’s certainly not helping so will need repointing to prevent future problems. the particles and by-products of this can cause their own damp problems to appear in or on the chimney. 2,233 posts. 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. 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. Discussion in 'Building' started by Km32, 21 Jan 2011. These patches usually come and go. of course if not, since I am working in building industry I never had a condensation problem on the chimney breast- this is nonsense ! 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. 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. 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. Condensation can occur when ascending combustion gases meet cooler temperatures in higher parts of the flue, finally dropping below the dew point. 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. The act of burning fuels (wood, gas etc….) The best way to resolve this problem is by inserting a chemical DPC into the base of your chimney. The wall outside is roughcast and appears to be sound. Brown stains on your lower wall are a sign of rising damp. As mentioned above some older chimney breasts do not have a Damp Proof Course installed. 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 … can create massive quantities of water vapour that progresses up the chimney stack, getting cooler as it moves upwards. Examine your roof for broken or missing tiles – remember to check your entire roof and not just the surrounding chimney stack area. Inspect your guttering for cracks and faults which could be exposing your walls to moisture and damp. Do you share a chimney with your next door neighbours? 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. The moisture can damage your walls and ceiling. Ventilation in the form of air bricks should also be fitted into the brickwork near the top of the stack to stop internal condensation. Moisture can enter the flue anytime it rains, without a chimney cap. 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. Apply the aforementioned salt neutralizer to the plaster surface (after stripping any wallpaper or paint) and allow it to dry (following manufacturer’s guidelines) correctly – you may need to give it up to a few weeks! If so then there is the chance that any work that they have carried out is the cause of your damp chimney. If you are suffering from damp issues in your chimney area and you have either a wood or gas burning stove installed then get your flue inspected right away!! Visual chimney damp problems are usually easy to identify, however finding the cause of the damp is often more difficult. If penetrating damp has been diagnosed as the source of damp the chimney needs to be checked and repaired where necessary then to stop the further ingress of water we recommend the application of a masonry water repellent to the whole exposed chimney to prevent water ingress which will protect the area from the effects of weathering for a good period of time, if Microshield Ultra is used this could be 25 years upwards. All of these features help to prevent the penetration of water via wind pressure, gravity and also tension on a surface. Check to see if the lead used to seal your roof to your chimney stack is cracked, coming away from the surface or looks in poor condition. 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. 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! As moisture travels from wet to dry areas, the source of the chimney damp doesn’t necessarily need to be on the stack itself. Any staining caused on these patches, in most cases, is the result of soot and other particles that have also managed to creep through the wall over a period of years and this is also occasionally due to the type of room e.g. Permagard is a leading manufacturer and supplier of basement waterproofing products, damp proofing membranes, and structural repair products. Sealers (silicone etc….) If your chimney is open-topped you may notice that once there is heavy precipitation the rain will pour into your chimney. 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). 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. • A chimney cap prevents water from entering the chimney. Keep up to date with our DIY projects, tips and latest deals, © DIY Doctor Ltd 2021 All Rights Reserved. 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. Can you see any splits or cracks in the mortar? 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. get some images of inside the breast. bristolbaron. Have a polite chat and ask them to confirm any work they have carried out relating to the chimney area, even going back a few years as occasionally chimney damp issues take quite some time to become apparent. 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. How to handle condensation in the chimney Originally published March 17, 2012 at 6:00 am Updated March 17, 2012 at 8:01 am You will need to protect the fireplace insert from moisture problems. We work with the industries best to ensure that we recommend only reliable and trustworthy tradesmen. 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. It’s possible ~ Smell from recently capped chimney While we strive to provide relevant information to all homeowners, some of the material we publish may not pertain to every area. In the room below, it is necessary to have chimney vent installed just below ceiling height. 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. Broken or blocked gutters can cause rainwater to filter and collect in unwanted areas causing water ingress and damp in your chimney. We regularly get questions here at Permagard about what’s causing damp patches around a chimney and how to stop it. in your loft space. Your checks will have to be thorough as in some situations it can be a little hard to spot. How to seal a chimney. We thought condensation … • A chimney cap can stop downdrafts from entering the home. 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. Victorian house, 3 storeys. The answer is yes, especially if there is little or no ventilation. If your chimney is capped, examine the cap for signs of damage. 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. Open chimney pots may be allowing rainwater to enter your chimney. Chimney cap prices: $25-$135 | Galvanized steel chimney cap; $40-$165 | Aluminum chimney cap; $45-$215 | Stainless steel chimney cap; $175-$650 or more | Copper chimney cap; $250-$600 | Decorative non-metal chimney cap; 20%-40% premium | Custom-sized caps in all materials; Supplies prices: $5-$15 | Screwdrivers and pliers; $4-8 | Tube of construction adhesive or RV caulk … 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. 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 contractor has removed the chimney pots and all that is visible from the ground is sloped mortar on top of the stack. Typically lead is lapped and layered, soldered or sealed using silicone to create a continuous run, and over time these joints can become weak and split, or in fact the lead itself can become weak and crack. 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 … 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. 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. To find out more about closing off or blocking up a fireplace, have a look at this project. If you suspect rising damp explore the possible causes below. Hygroscopic Salt Chimney Damp The Problem. We use the salt neutraliser manufactured by PRS as we have found it to produce consistently good results. coal, wood etc….). If there are issues get these fixed as soon as possible to minimise the chance that they’re causing your damp. I have also had some condensation enter the basement by way of the clean-out. 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. Burning coal and wood releases tars and salts that then settle into the chimneys of older homes. Fix – There are several ways to remedy this problem with varying degrees of difficulty. As you may have guessed from the title this can cause many problems including damp in your chimney. As we all know fuels generally come from the ground (e.g. Broken roof tiles can allow damp into your roof timbers, Ventilation (capped or sealed chimneys and bricked up fireplaces). 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. Does your chimney breast have a DPC (Damp Proof Course – layer of slate or plastic between brick courses about 6 inches above ground level)? 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". 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. can also be used to seal any other small gaps but as said most of these substitutes are no match for using lead and doing the job properly. When this process occurs over decades, it can cause unsightly chimney damp. is there a sealed cap or mortar covering the top of the pot?) Seeing your post reminds me of a situation I came across years ago with similar symptoms. You may need the services of a roofer to do this. These are usually deposited as a result of burning fuels. If you are experiencing a severe level of plaster damage then this is most likely down to a water leak so you will have to use the checks listed above to trace and find the leak and fix it. If the chimney is capped, damp appears and goes when is raining, and also damp dust is dropping down- so this have to be condensation ! ) How long does damp take to dry out? 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. This then prevents cold air from being trapped in the chimney void as air is still allowed to flow through the chimney. Joined: 21 Jan 2011 Messages: 2 Thanks Received: 0 Country: When i had a loft conversion done a disused flue was capped. This is best identified from inside the attic or roof space. I have a problem with condensation on the wall between my living room and the chimney and I would be grateful for suggestions as to how to tackle this. Be as amicable as possible as there is huge potential for disagreements, especially where money is concerned. Dpc bridging pots or stack are capped and sealed at the signs, potential and. 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