If you look at any major city in the UK, a big chunk of the housing stock is going to be over 50 years old. Some might even be over 100! So, it’s not really surprising that some properties and their materials might not perform as well as originally intended. 50 years is a long time, and there are plenty of reasons materials would degrade in that time. One of the most common issues we see from this is finding damp where it shouldn’t be – inside the house.
If we told you to picture a property with damp, what would you see? Odds are, you’d get an image of a dilapidated, poorly maintained property that no one would want to live in, with black mould climbing up the walls. And there are absolutely cases of damp that are like that. But most damp cases are very different.
It’s an issue that can affect any property, even those that are very well–kept. The owners might not even realise they have a damp issue until it’s time to sell. The good news is, if the people living in the house every day haven’t noticed it, then the damp probably isn’t a big problem. But if you’re a buyer, you still need to be able to check for hidden dampness as it can give you an indication that work will be needed in the near future.
So, what counts as damp? Basically, any form of water ingress within a property that develops as a direct result of a failure of waterproofing to the external envelope, or other failures within the building like plumbing leaks or gutters in disrepair. A big tip–off that hidden damp could be a problem in your home is frequent condensation inside the house, especially when it shouldn’t be there.
For well over 100 years properties in the UK have been fitted with damp proof courses (otherwise known as DPCs). These come in a lot of different materials and styles, including engineering bricks, slate, bitumen and polythene. Their purpose is to create a protective barrier against damp rising up the walls of the building.
The passage of time, vibrations or poor workmanship can cause these to become damaged and need to be replaced. At that point, builders will usually recommend the damp proof course is replaced with either a chemical damp proof course (which soaks into the bricks) or in some cases a physical damp proof course. This can be difficult and expensive, since it involves cutting into a wall to insert the new DPC, so chemical replacements are the more common choice.
There’s a lot of discussion in the industry about whether or not rising damp is real, and we’ve noticed that this leads to a lot of damp assessors relying too heavily on treatments to overcome damp issues. However, in our experience, these solutions aren’t appropriate in all instances, and we see evidence of this in property inspections. In fact, before a recent property inspection the agent cheerily told us that the damp issues had just been addressed, and to expect the decorative condition to be poor.
When we got into the property, we found that a chemical damp proof course has been injected to replace the old damaged one, but there were multiple other causes of dampness that hadn’t been addressed.
Over the years a lot of properties have been modified and extended multiple times for lots of different reasons. Inexpert workmanship or the gradual degradation of components following that building work can lead to internal dampness, which can often look like rising damp and lead to an incorrect assessment.
For example, a previous owner might have installed a new driveway, which means the external ground level needed to be raised to above the line of the damp proof course. When this happens, it doesn’t matter if the DPC is working properly, since the brickwork above the DPC will become saturated anyway. Similarly, if you or your neighbour props up items for storage against an external wall, or installed raised planters or decking, you can get a similar result.
We often find dampness in properties that have been modified in some way – like being retrofitted with cavity wall insulation. If the mortar pointing between bricks on the outer walls isn’t well maintained by the homeowners, this lets the outer brickwork become porous, which then saturates the cavity wall insulation and damp develops as the wall tries to dry out internally. This is very common, and yet many damp proofing contractors will completely overlook it, just like the one we mentioned earlier.
Sometimes we find that the issue is as simple as a blocked and overflowed gutter that’s sending a large amount of water to a particular location. This causes similar issues to the ones above, but due to the concentration of water the consequences can be even more extreme. So it’s important to remember that there are many reasons a property might have damp, and it takes an expert eye to fully diagnose the cause.
We’ve already explained a couple of different reasons that water might be getting into your home, including:
But you might have seen the term ‘water penetration’ in your reports. This terms effectively means any water ingress that isn’t a direct result of a failure in the damp proof courses. It isn’t all that unusual for water to get into a property because of a roof defect or a plumbing leak, and we’ll talk more about that in the next blog.
Damp really isn’t as simple as it seems, is it? The good news is, that’s what we do best. Building pathology is a core skill for building surveyors, and our experienced team are well versed in diagnosing the causes of damp, as well as setting out a plan for any necessary remedial work. If you’d like to know more, just give us a call on 023 8155 0051. We look forward to helping you return your house to a warm, comfortable and (most importantly) dry environment.
We also have a range of videos talking through various aspects of Dilapidations. You can access them via our website or our YouTube channel.
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Tim set up Harrison Clarke Chartered Surveyors in July 2017 following a series of public and private sector surveying roles, having previously worked for the University of Cambridge, Rund Partnership, Goadsby, and CBRE.
Tim has degrees in building surveying, construction project management, and business administration.
