Why is There Damp Under Floorboards?

20 April 2021

Damp is a huge problem when it comes to property care. The fact of the matter is that damp can make its way into your property via any exterior wall, or even develop thanks to an overabundance of condensation in some cases. A big question a lot of people might have then is why is there damp under the floorboards of their property?

The answer might be a little more complicated than you might have hoped – but the good news is that in most cases a trained specialist who understands both the diagnostic and treatment side of damp surveying will be able to help you find the root cause of the problem and assist you in solving it.

So, no more preamble; here are the most common reasons why you might find damp under the floorboards in a property, and how you might go about getting it removed.

The Most Common Reasons Damp Gets Under Floorboards

Damp is by its very definition moisture. So, right away you should be able to understand that the key reason that damp has taken root underneath your floorboards is due to moisture that has permeated into the floorboards (or what lies beneath), and it’s the source of that moisture that is causing the damp.

There are a couple of main reasons that could be the chief reason for damp appearing under your floorboards. We will run through them here, and it may well be the case that you easily recognise one of them as the reason your property has damp.

Rising Damp:

Rising damp is one of the main causes of damp appearing under floorboards on the ground floor of a property. Traditionally, rising damp occurs when moisture enters the properties different constructive properties – most commonly masonry.

Usually the moisture will permeate the brickwork, and travel upwards through the masonry thanks to capillary action, this is what gives it the name rising damp. Typically, the moisture enters the constructive materials through the earth that the property has been built on, and can usually be down to a fault in the construction allowing the damp to enter.

This fault is usually the lack of (or a faulty) damp proof course. This is often how rising damp might make it underneath your floorboards as well, as the moisture in the earth underneath your property could easily find its way under your floorboards if your damp proof course (or other damp proofing solutions) under your floorboards aren’t working correctly.

Again, this is a cause of damp under floorboards that will primarily be found on ground floor properties, as rising damp stems from moisture within the earth rather than from other sources.

Is the Damp Under My Floorboards Rising Damp?

The easiest way to spots the signs of rising damp as the source of the damp under your floorboards is by looking above, as well as below the floorboards.

Commonly, rising damp below the floorboards will be present in the space below the floorboards and the floorboards themselves will be moist, or even fully wet to the touch. That might even extend to the underside of the floorboards, or in severe cases the entire floorboard.

Check the walls, skirting boards and other connecting materials that run past or link with the floorboards for signs of damp or excess moisture. This could look like peeling paint above the floorboards, sodden wood and swollen or even warped joists. These signs all become more prominent during rainfall, or high humidity weather, so be sure to keep an eye out at these times.

If you notice these signs, and want to learn more about the damp under your floorboards and how to treat it, then get in touch with a specialist immediately.

Penetrating Damp:

Penetrating damp is another form of damp that arises out of faulty construction materials – though it does differ from rising damp.

In fact, you may well find penetrating damp in the same places that you would find rising damp – but unless you are a trained damp surveyor, the difference might not be all that apparent to you. One notable difference for example is that penetrating damp is much more likely to be found under floorboards above the ground floor, and often you will see signs of it above the floorboards and around the property itself.

Penetrating damp usually enters the property thanks to water entering the masonry when it shouldn’t – leaking pipes, bad guttering and pooling water around drains are all major causes of penetrating damp, and allow for the moisture to enter the property horizontally, opposed to the vertical nature of rising damp.

Because the nature of penetrating damp means it can enter the property horizontally, it could theoretically be present at any layer of the house, and it may well be the case that you notice it on the exterior of your building before you discover it on the inside. Damaged brickwork for example would be a key indicator on whether you might have an issue with penetrating damp under your floorboards, or through your property.

Is the Damp Under My Floorboards Penetrating Damp?

If you are concerned that the damp under your floorboards is a result of penetrating damp, then you should be aware of the following common signs.

First, as we said before, penetrating damp usually enters the property via external construction flaws. If you believe there is damp under your floorboards, or have seen definitive proof, check the exterior of your property close to the underfloor damp to see if there might be a defect that the moisture is entering through. If there is, that is a major sign of penetrating damp.

Penetrating damp might also present itself in a wider pattern than just under your floorboards as well. You may notice larger patches of damp in the same space as the damp under your floorboard, with problems like black mould on the walls, peeling wallpaper or crumbling paint.

If you do find these signs in the same space as the damp under your floorboards, it could well be a sign that you have penetrating damp. In that case, you will want to get a damp proofing specialist out to your property as soon as possible to help you rectify, treat and stop the damp from having any further effect on your property.

Condensation or Poor Ventilation:

It may not come as news to some, but condensation and a lack of adequate ventilation are leading causes for the build up of damp problems within a building.

If there is damp below the floorboards on a ground floor level, then it could well be that you have not got sufficient ventilation to help disperse the moisture rising out of the earth, meaning that the moist air instead comes to rest on the different building materials below your floorboards, and as the temperature changes this air will turn back into a liquid form, and from here become damp.

You will notice that many properties include masonry with holes and ventilation built into the ground level close to the floor, and it’s for this very reason, as trapped moist air with nowhere to go is likely going to present itself as damp, and cause a much larger problem for the property owner as time goes on, and the damp goes unnoticed.

A similar problem can arise out of excess condensation not being allowed to ventilate correctly. If you have a ground floor bathroom for example that is not fitted with sufficient ventilation, then you may find that condensation allows for the build of damp not only on the walls of the bathroom, but also on the ceiling itself.

In this situation, its highly likely that the damp stemming from the condensation is not just sat on the ceiling of your bathroom but is also spreading beneath the floorboards of the first floor.

Is the Damp Below My Floorboards Because of Bad Ventilation?

If you are concerned that a lack of ventilation in your property has led to a build up of damp, then the first thing you should check is the ventilation systems you have in place, and how they are faring. If, for example, you find that the air bricks just above the ground of your property are blocked, then you may well have fallen victim to a build up of condensed air from the ground below your floorboards.

In other situations, the very presence of condensation will be enough to tell you if your ventilation systems are working correctly. Damp or black mould on a ceiling for example is enough to tell you that you have fallen victim to interstitial condensation, and leaving the problem unchecked is only going to allow the damp in the space between ceiling and floorboard to worsen.

In this situation, you will want to reach out to a damp treatment specialist to advise you how best to not only open up the ventilation options in your property, but how to treat the damp that may have already formed.

You will also want to look into the different forms of ventilation systems available to you as well, options like positive pressure systems, extractor fans, or even simply opening windows and changing certain aspects of a day to day routine will all go a long way in changing the way that moist air behaves within a property.

Leaking Pipes:

Unfortunately, with pipes running underneath properties and through the underfloor spaces, a lot of damp and flooding problems can be traced back to burst, leaky or broken piping.

It’s fairly obvious, but if you live in a property that has been free from damp problems for a long time, that then sprouts damp issues which follow a very linear path along pipes, then it could well be that a burst pipe is causing significant issues within your property, or under your floorboards.

Leaking pipes can happen for a number of reasons. Corrosion, bursting due to cold weather or even from poor installation – the fact of the matter is that this is a common problem, and the sooner it is dealt with the better.

Is the Damp In My Floor Due to Leaky Pipes?

This question should be a pretty easy one to answer yourself, especially if you are familiar with your properties water pressure and operation. If you happen to notice one day that the water pressure from a tap for example is lower than it should be, or responding slower to your actions, this might denote a leak.

If, at the same time, you notice damp below floorboards, damp patches on the ceiling below where the pipes run, or even just a damp smell below the floorboards, you should talk to a plumber immediately for help – and then turn to a damp proofing specialist to see how any potential damage could be fixed.

If you have a good knowledge of pipe repair then you may even be able to fix the leak yourself, but what is important is that you act quickly, before the damp increases in size, spreads, attracts black mould or even leads to flooding.

Removing the Damp Under Floorboards

Every single one of the most likely scenarios to produce damp share the following in common: They can all be recognised by a damp proofing expert, and the most pertinent course for not only removing, but stopping the cause of the damp will also be apparent to the same damp surveyor.

Commonly, rising damp is treated with a damp proof course, penetrating damp with a blend of masonry repair and the use of damp proofing materials on affected areas. Ventilation and condensation are easily recognised and treated with behavioural adjustments and ventilation installing, whilst leaking pipes can be fixed by a plumber.

All of these different methods stop the growth of damp within your property, but there is still the question of repairing the damage done, removing black mould and even replacing broken materials. All of these steps can be assisted and made clear with the intervention of a damp proofing specialist.

Our team is ready to head out to your property, find the cause of damp under your floorboards and recommend not only the next step in removing that damp, but undertaking it themselves thanks to their wealth of experience and training. Call 0800 288 8660 or request a survey here if you believe that you have damp under your floorboards, and you want it gone.