The Causes of a Flooded Basement

Flooded basement

October 13, 2021

If you have a basement then you are already aware of just how much of an incredible and home changing space they can be.

Of course, all that can change in the event of a flood. If your basement or cellar is the subject of a flood, then you might find that your floor, your walls, your decorations, and any expensive furnishings or electronics you have can be entirely ruined.

So, outside of understanding how and why basement waterproofing is important and what a quality sump pump can do in terms of keeping your property dry, it might be useful to learn exactly what leads to a basement leaking, and the potential steps you can take to ensure damage is kept to a minimum.

The Main Causes of a Leaking Basement

A leaking basement isn’t in itself surprising. In fact, when you have your basement surveyed by a professional the actual cause for your leaking basement is going to be pretty easy to discover and categorise.

What follows are some of the main reasons that a basement might leak – and if any sound familiar or echo the circumstances surrounding your basement, then it could well be time to get in touch with the experts.

Lateral Pressure

Lateral pressure is one of the leading causes of damp in basements and cellars, and it’s not hard to see why.

First off, you need to understand what lateral pressure is. When soil absorbs water, it naturally expands, and that can be a real issue when soil is compacted around the basement of a property. If soil surrounding the basement begins to expand due to water, you might find that it can exert quite a lot of force onto the basement walls themselves.

This expansion of the soil that pushes into your walls might not seem significant, but over time and in heavier bouts of rainfall you may find that that pressure grows and grows, and eventually causes cracks and other faults to form in your basement.

This is, obviously, very bad when it comes to the health of your basement’s walls and for the overall dryness of the basement itself.

Cracks appearing in your basement walls caused by high levels of moisture laden water means one thing: leaks. That water that was expanding that soil as it soaked in will now find its way through your basement’s newfound cracks and it could cause damp, it could cause floods, and each of these can cause a lot of stress to say the least.

Sadly, there isn’t a lot you can do to anticipate or combat the onset of lateral pressure in your home. Outside of consulting a basement waterproofing expert to survey the ground around your basement to ascertain potential dangers, you will have to rely upon your basement waterproofing setup in conjunction with your sump pump to combat and protect your basement against incoming water.

Hydrostatic Pressure

Hydrostatic pressure is a little simpler to understand than lateral pressure, but that isn’t to say its any less damaging or worrisome.

Where lateral pressure is the result of soil becoming sodden and pushing onto a basement’s exterior facing walls, hydrostatic pressure is where the amount of water building up around a basement’s exterior wall is absorbed into the walls themselves, rather than the soil.

So, not only will the water absorb directly into your walls allowing for the spread of damp, but that spreading damp will then weaken other areas of your basement wall, which in turn might let in more moisture, and that could lead to cracks…you can see how the pattern easily spreads and allows for expanding destruction in your basement.

This is a common and dangerous form of water entering a basement, and can be made much worse in months where rainfall levels are high, the outdoor temperatures are cooler, and the warmth of the basement acts to draw more moisture out of the soil into the walls.


Believe it or not, one of the main reasons that your basement might be taking on and retaining water could have nothing to do with external factors or water ingress whatsoever.

Condensation is a leading form of damp development and water damage throughout properties in the UK, both in above ground and below ground structures.

Condensation is a very easy to predict and understand process. When humidity is created in spaces where there isn’t adequate ventilation to control and remove it, that humidity can easily transfer itself to different surfaces, which on contact transfers the humidity from a gaseous state to a liquid one.

All this means that a properties walls can easily become covered in moisture, despite there being no leak or other internal flood to speak of. This is a big enough problem in the likes of bathrooms and kitchens, but consider how poorly ventilated many basements and cellars are, and you might begin to understand why build up of condensation might lead to a leak.

Imagine you own a basement that you use for the likes of entertainment, or even as a home gym. Any moisture generated in these environments is going to be entirely incapable of escaping, and as a result will transfer to the surfaces within your basement.

Over time, this continued build up of condensation is going to allow for the onset of damp in your basements walls – or any surface that allows continued moisture to settle. This means that not only are your basement or cellars walls going to be the perfect breeding grounds for black mould to begin life and grow on, but your basements walls themselves are going to be compromised when it comes to structural integrity.

Damp is capable of ruining mortar, destroying brickwork and generally compromising the integrity of any structure it manages to permeate. Now apply that process to a basement or cellar. You are going to find that any exterior influence that could be acting on your basement manages to break through much easier.

External lateral pressure, exterior natural drainage that previously ran alongside your cellars exterior walls, or even just groundwater that would otherwise soak or evaporate harmlessly will now have a much easier time pushing its way through your walls, and potentially causing even bigger leaks in the basement itself.

You see, with condensation you don’t need to wait for a leak to begin experiencing the nasty side effects of water damage and damp – they will occur anyway. That doesn’t mean you are going to be free of potential leaks though – if anything, condensation makes that possibility much more likely.

Relying on Your Waterproofing Solution

What was previously described are the main ways that leaks might make their way into your basement or cellar – the real question though, is whether your basement waterproofing is up to the challenge of protecting your basement against water ingress?

If you have had a waterproofing system put in place, and are relying on a sump pump to channel away water that makes its way into your basement, then its vital that your sump pump is kept in perfect running order.

That means you will undoubtedly benefit from regular maintenance performed by expert sump pump engineers, and our team can provide a reliable service scheduled around your own needs.

These routine inspections will help you to avoid potential catastrophe stemming from a malfunctioning sump pump, and keep your basement dry even when the rain is heavy and the ground is sodden. Not got a sump pump, or are interested in the waterproofing solutions available to you? Call us up today to discuss options and how to best protect your basement.



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