It’s no surprise to learn that chimney breasts can be susceptible to damp. After all, the chimney is one of the most exposed points of a property. In a country such as ours, with high levels of rainfall, damp problems are to be expected over time.
Add to this, issues with age and wear and tear and you can see why chimney breasts can be a source of damp. But why can damp still be evident, even when the chimney breast has been removed? In this article, we look at why damp can occur after chimney breast removal, and how you go about fixing it.
If you can see damp after chimney breast removal, there are two possible causes. The most likely cause is hygroscopic salts. Penetrating damp is another possibility, although less likely in this instance.
Both can require a significant amount of work to rectify the issue. Therefore, employing the services of a damp proof professional is sometimes recommended. However, this is not always the case, and the necessary work can be straightforward, if a little awkward.
What to Look for – Signs of Damp Where Chimney Breast Was Removed
In recent years, people have moved away from having traditional open fires in the home. As a result, chimney breast removal has become a common task in home improvements. This is especially true in the renovation and refurbishment of period terraced properties.
Removing the chimney breast can be a big job and the builder can end up removing a complete leaf of bricks. Following this, new bricks will need to be installed to replace the missing layer. The wall can then be plastered and skimmed. If the job is done well, you Should never even know the chimney breast was there.
For a professional, this should be a straightforward job. Yet, following this type of work, many homeowners have reported problems with damp.
Damp patches can be visible on the wall where the chimney breast used to be. In many cases, homeowners will first look too DIY fixes, such as using an anti-damp paint. Yet the damp patches reappear months later. These are tell-tale signs of a more serious issue that can’t be fixed with a lick of paint.
Hygroscopic Salt – What is it?
The most likely reason for such damp patches, is hygroscopic salt. Essentially, this is a legacy issue, dating back to when the chimney was in full working order.
First, we need to explain what hygroscopic salt is. In the case of a chimney, it is a by-product, resulting from the burning of fossil fuels. For example, gas or coal.
As fossil fuels are formed underground, they absorb certain minerals. When coal is burned on a fire, various minerals are released. Over time, these minerals will build up on the inside of a chimney in the form of salts.
In itself, the build-up of salt over a period of time isn’t a major issue. The problem emerges because the hygroscopic salts are highly absorbent and attract moisture. This is what leads to the damp forming.
As with all damp, once the damp has penetrated the brickwork or plaster, it becomes more difficult to remove.
Why are Hygroscopic Salts So Damaging?
The real issue here is the build-up over time. Even if the chimney is no longer in use, the accumulation of hygroscopic salts and the moisture they attract will cause damp. Even if the chimney breast is completely removed. Unfortunately, at this point the damage has already been done.
The salts migrate to the wall’s surface where they are exposed to moisture. So, there is no chance for them to dry out. Condensation in the home is attracted to the salts and this causes damp patches.
Salt-contaminated moisture is a stubborn problem. It will migrate through new and old brickwork. Therefore, even when you lay new bricks and re-plaster after the removal of the chimney breast, the problem of damp can persist.
Other Possible causes of Damp where a chimney breast was removed
Obviously, there are other potential causes of damp following chimney breast removal. These are mainly the result of penetrating damp.
It is sensible to check the outside to ensure that the pointing is sound and that there is no damage to the external bricks. Also check any down-pipes and guttering that may be in that area. If there are issues here, excessive amounts of water could be running onto the walls and penetrating through.
If you can’t find any external issues, and you can rule out penetrating damp, then you can deal with the issue of salt contamination.
Fixing the Problem
Unfortunately, to remove hygroscopic salts, there is no simple, quick fix. the wall will need stripping back to the bare brickwork. Following this, it will need to be left to thoroughly dry out. Once the wall is entirely dry, a salt neutraliser should be applied.
This whole process could take a considerable amount of time, especially if the problem is identified in winter and the walls take longer to dry.
You can speed the process up by using heat and extracting moisture with proper ventilation. A dehumidifier can work very well for this, you can learn more about dehumidifiers here. Once the wall is entirely dry, you can proceed to re-plaster and decorate.
Just be aware.
If the process is rushed, the problem will resurface.
If you are having problems identifying the exact cause of damp, and aren’t confident to carry out repairs yourself, It may be wise to hire in help. Remember, the worst case scenario is doing a poor DIY job and the problem returns. When this happens all your hard work will go to waste.
With this type of job, it is often worth hiring an expert to diagnose the problem and offer the best solutions.
In many cases this can be a free call out, or in some instances there will be a small call out charge. Following the review and recommendations you can then decide if you want to do the work yourself, or hire the company to do it for you.
The best way to find local, reputable, damp proofing companies, is to use online comparison sites. By doing this you can see previous customer reviews and get multiple quotes from different companies.