Condensation formed in cellar with early signs of black mould spots

What Property Care Issues are Most Common in Basement Flats?

19 September 2023

If you live in a basement flat then you might already know that your living space is more susceptible to certain property care issues than other spaces.

The fact is living in a basement flat can have all kinds of issues that others living above ground might not come into contact with as often. With that being the case, it might help to understand some of the most common problems you might encounter, as well as how they can be identified and treated.

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Why Are Basement Flats More Likely to Have Property Care Issues?

The simple fact of the matter is that basement spaces are located below ground, in spaces that may traditionally have not been designed for living. This means that the flat itself might not be up to waterproofing standards, that the level of ventilation isn’t what it should be, or even that the damp proofing measures in the basement itself aren’t up to standard.

Why might this be the case? Well, in many instances, basement flats are conversions. A space initially meant for storage might not have the same facilities for a space in which people are trying to live. This doesn’t extend to just things like damp proofing or waterproofing either, simple elements like windows that open or ventilation options may be more limited than they would be in a purpose-built flat.

This is a pretty vague overview on the situation though, so we can look at some different property care issues a little more closely, and see why they might effect a basement flat more.

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Signs of damp on internal wall in house

Damp is a problem that everyone is familiar with. Moisture in your properties walls is never a good thing, and it can appear for a number of different reasons, but when you are living in a basement flat you might notice it more often than those living in an above ground flat.

This is because basement flats are located below ground, surrounded by earth which is, naturally, damp. If the basement flat hasn’t been waterproofed correctly it won’t be long until the damp in the ground surrounding the basement makes its way into the below ground walls, causing a visible and potentially lasting penetrating damp problem.

The way that a basement takes on water from the surrounding ground can happen in one of two ways. The first is via a process known as lateral pressure.

Lateral pressure is when the soil surrounding a below ground structure, like a basement flat, becomes sodden after it absorbs moisture following rain, snow, frost, dew – however the moisture gets in there.

When that soil takes on moisture, it naturally expands. This expansion can press onto your basement walls, and over time this leads to cracks, leaks, and other compromises in your wall which will inevitably lead to penetrating damp problems – and, if left completely untreated, it could even lead to flooding.

The other route penetrating damp can take into your walls is via what’s known as hydrostatic pressure. Much like lateral pressure, hydrostatic pressure involves the build up of moisture in the ground, but instead of it causing the soil to expand, the moisture presses onto the below ground walls directly, causing those same walls to absorb the moisture directly.

In either instance, it won’t be long until penetrating damp presents in your wall and you are left with a nasty problem.

Luckily, this kind of penetrating damp can be solved with a proper waterproofing solution, you just need a professional to help you understand what specific waterproofing elements you need.

However, external forces might not be the only cause of damp in your basement flat.

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Condensation formed on a double glazed window

Condensation is one of the most common property care issues that people in basement flats complain of.

Because condensation is primarily caused by a combination of everyday living and a lack of ventilation, a basement is almost the ideal environment in which condensation can thrive.

For example, if you have a basement flat that features a kitchen, a washer, a dryer, and a bathroom, chances are that in a day you can be creating a lot of hot, humid air – and if your basement flat doesn’t have adequate ventilation in place then all of that hot humid air is going to stay in the basement, and become condensation.

This is why basement flats are more prone to condensation based damp, especially when these basement flats aren’t outfitted with exterior opening doors and windows, extractor fans, or positive pressure units.

All of these features are key when it comes to increasing the level of ventilation in a basement, and key if you want to make sure that the condensation build up doesn’t lead to a lasting damp problem, or black mould spreading.

You can look into all different kinds of ventilation options, but if you are struggling to keep condensation under control then you can talk to our team about arranging a condensation survey, and we can help you take the steps you need to reduce the amount of condensation being created in your property.

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Black Mould

Closeup of black spot mould on a skirting board

Black mould is a problem that stems from damp, and thrives in warm, moist environments.

Basically, a damp basement is a breeding ground for black mould fungus. If you live in a basement flat, you might have already had a run-in with black mould, or could even have a problem with it whilst you are reading this.

We have plenty of material on black mould the causes, and how to treat it, but the simple version is this: Damp, present in whatever form (most commonly condensation in a basement), will create the ideal breeding ground on which black mould can grow. You should also know that until the damp has been treated the black mould is only going to come back time and again.

Basically, address your basements damp problem before moving onto mould eradication. The actual removal of the mould itself is easily done, and takes very little effort provided you have the correct equipment.

Just use the mould eradication spray on the effected area, leave it for thirty minutes, then scrub vigorously and repeat until the mould has been cleaned away. You may well need to repaint or repaper the surface the black mould has effected, but once you have eliminated the source of the damp in your basement flat then it’s much less likely to return.


Basement flooded with water


Flooding is by far one of the most common property care complaints of those who live in basement flats.

These floods don’t even have to take the form of the kind of knee deep, news leading images you might be thinking of, but they can be a slow and steady influx of water that might ruin a particular corner of a basement flat, allow damp to build up, or even ruin your wallpaper or paintwork.

The reason for basement flooding? Inadequate waterproofing. These days every property must comply to the standards set down in BS8102:2022, the British Waterproofing Standards – but that is these days.

There are plenty of older properties that might not comply to these standards, and if they have had the basement converted into a flat without a proper update to the waterproofing installed then you could well have a basement not built to cope with the likes of the hydrostatic or lateral pressure like we described earlier.

These problems might get worse in winter, the flooding might slow down or stop in summer, but if you do have a flood in your basement flat, it’s indicative of a larger problem to do with the waterproofing of the basement itself.

This isn’t an unsolvable problem. Basement waterproofing can take many forms, and our team are highly skilled and well experienced at installing both of the types of BS:8102 complaint waterproofing systems which can be installed following construction.

First you have Type A Waterproofing, also known as tanking. This is a waterproof slurry applied to the below ground walls of a property, stopping water from making its way in. Then you have Type C waterproofing, also known as a cavity drain membrane system.

Type C waterproofing is much less invasive, with it being made up of a membrane affixed to the interior of a basement, designed to collect the water and channel it, via internal drains, into a sump pump, which safely pumps the collected water into a proper disposal point.

You can always contact our team about basement waterproofing solutions online, or call 0800 288 8660 to talk to us about any property care issues you are having in your basement, and the best way to deal with them.