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Mould whines: All you need to know about damp

There’s no doubt about it, winter firmly upon us and the countdown to Christmas has started! With high streets full of festive grottos and frantic shoppers, what could be nicer that escaping the crowds and curling up in your cosy, warm property?

Unless, that is, your property is plagued with damp. One of the most problematic issues that landlords face, dealing with damp and mould problems can be an ongoing headache for landlords and tenants alike, and as well as being unsightly, can lead to serious health problems for your tenant and structural issues within the property – so much be taken very seriously.

If your tenant reports a case of damp or mould in your property, the first thing to do is identify the type of damp you’re dealing with. Rising damp, penetrating damp and condensation are the three primary problems you are likely to be facing, and although each need managing swiftly, it is important to ascertain which is the issue affecting your property, as each requires a different form of management – and the responsibility may not lie with you.

If the mould has been caused by a rising or penetrating damp which has been caused by structural issues (dripping pipes, dodgy damp proof course, leaky roof) - the blame will fall squarely at your feet, as you are responsible for the maintenance of the property under Section 11 of the Landlords and Tenants Act, and therefore the repair and maintenance will be your responsibility. However, if the damp is down to your tenant’s lifestyle choice, such as if they do not adequately heat the property, or if they are drying washing without adequate ventilation, they could be in violation or terms of their tenancy agreement.

However, whether you are to blame or not, deciding whether or not to manage the mould isn’t that clear cut. Under the Housing Health and Safety Rating System (HHSRS) treating damp is a mandatory repair, and there can be serious consequences for failing to carry out these repairs properly.

Rising Damp

What causes it?

Rising damp is a particularly tricky – and potentially pricey problem to deal with.

It is caused by water ingress through the masonry structure of the building, moving up through brick walls eventually becoming visible inside the property. This issue can rumble on undetected for some time, causing unknown damage to the structure of your property before it is noticed. Your tenant may be alerted by things such as:

  • Tide marks on plaster, wallpaper or interior paintwork
  • Damaged skirting boards
  • Tide marks on carpets
  • Blown wooden/laminate flooring

How do I fix it?

Most newer properties have a damp proof course built in at the time of building, it is a requirement of modern building regulations, however if you own an older property there is a possibility that you may not have a damp proof course in situ. A damp proof course is a very simple but effective method of stopping water ingress in it’s tracks, with a strip of plastic or impenetrable material (slate etc) inserted into the brickwork just above ground level. Many buildings also have a damp proof course laid under the ground floor, meaning that water cannot seep up through the base of the property.

If you believe that you have rising damp in your property, you need to act quickly, as there is the possibility that it could have been seeping into the structure of the building for quite some time – there is no time to lose!

The first thing to do is to work out whether or not you have a damp proof course in place. If you do, you should explore why the damp has managed to overtake the level of your existing protection – a specialist should be able to assess if there is any damage to your existing DPC, and if so help you fix the issue.

If you do not have a DPC in place, you may have a bit of work on your hands… there are two options available, chemical or physical.

Physical damp proofing involves cutting a horizontal groove along the damp wall, before inserting slate wedges, and finishing up with a mortar barrier, holding the new material in place and sealing the gaps from any water.

Chemical damp proofing is a less invasive alternative, but is not necessarily the best option should you find your property already suffering from rising damp. It involves removing all of the affected plaster (usually to a height of around 1.5m) before injecting your walls with a with a specialized solution designed to prevent moisture rising within your walls. Your walls will then need to be re-plastered with a special salt-retardant render before you can consider redecoration.

Installing an effective damp proof course is not a simple job, and it is wise to take advice from an expert if you are not 100% sure about how to go about doing this big job yourself.

Penetrating Damp

What causes it?

Although sometimes confused with rising damp, penetrating damp is an entirely different animal. If you own a property above ground floor level you may think you are safe from creeping damp blooms – not so! Penetrating damp is your worst enemy, and at this time of year, when the weather is closing in, bitter winds are leaving your roof exposed and gutters are full of fallen autumn leaves, it is easy to fall foul of this pesky problem.

Unfortunately, due to the fact that penetrating damp can take a while to become evident, it can niggle away at the property’s shell before it becomes evident to your tenants. They may report evidence of water ingress, the smell of damp, rooms feeling cold (especially in winter months), and plaster breaking inside the property. However, the ‘behind the scenes’ damage can include:

  • Plaster breakdown
  • Timber decay
  • Wet rot
  • Mould
  • Damage to brickwork

How do I fix it?

The first thing to do is to identify the culprit! Tracking down the location where water is entering the body of your property is key to stopping penetrating damp in its tracks.

The most common culprits are usually elements designed to handle water movement, such as gutters and downpipes – however also make sure that any entry points to the home (window seals, door frames) are tightly sealed. Your roof could also be potentially guilty, take a good look from the ground and see if you can see any slipped slates or obvious issues, and if you are able, pop into the loft and see if there is any evidence of water ingress, or even if you can see daylight through the slates from inside – a big hole from the inside looking out is never an ideal situation!

Once you have identified the culprit and fixed the root cause, you need to protect your property against further damage. There are plenty of products on the market that you can use to weatherproof the masonry, and it is as simple as painting a coating on the exterior wall, which will make it impervious to damp whilst still allowing the walls to ‘breathe’.

This is not a lifelong product, it will need to be maintained, so remember to build it into your regular maintenance schedule on the property.


What causes it?

Condensation is caused by warm, moist air finding it’s way to a colder surface - such as a window, or wall which hasn’t been warmed by any heating. When the warm air collides with the cold surface, it condenses, causing a liquid to form – condensation. If left unchecked, this moisture source can lead to mould growth, which can be very dangerous, not to mention unsightly.

Although usually blamed on lifestyle issues, condensation can be compounded by problems within the structure of the property. Common issues include:

  • Installation of plastic (UPVC) windows with no ventilation
  • Ventilation bricks blocked up
  • Fireplaces blocked up with no ventilation
  • Draught excluders around doors
  • Lack of ventilation to cellars
  • No extractor fans to kitchen and bathrooms
  • Bedroom windows shut tightly

You may have done all you can you make your property as warm and toasty as possible, but by doing so you may have unwillingly made it a haven for condensation and mould!

That said, all air contains a certain amount of moisture, and there are certain lifestyle issues that your tenant may have that could be making a condensation issue worse. These include:

  • Cooking with no ventilation – Creating steam on the hob, or from the kettle entering the kitchen adds moisture to the air – if this has no means of escape (via an open window) it is likely that condensation will form
  • Bathing with no ventilation: The most common issue is hot baths and showers creating steam with no ventilation -but even damp towels can play their part!
  • Drying clothes with no ventilation: A regular issue between landlords and tenants, drying wet clothes on drying rack with no ventilation releases lots of moisture into the property
  • Not heating the property: Failing to heat the property and warm up the walls creates a perfect atmosphere for condensation to form
  • Breathing (although this is allowed)! - By simply being alive the average human creates around eight pints of water in a twelve-hour period through sweating and breathing – although it’s fair to say that even the most diligent tenant can’t prevent this!

How do I fix it?

It really depends on what is causing the condensation - whether it is a property or lifestyle issue.

If there is an issue with the property that you have unwillingly caused, there are some easy fixes that you can implement to improve the air flow within the home, which should hopefully give way to better ventilation and less condensation for your tenant.

These fixes include:

  • Make sure there is an efficient heating system in place that is cost-effective to run, to encourage your tenant to use it!
  • If you have UPVC windows, ensure they are fitted with the vents – this allows for the windows to be securely locked by for air flow to remain.
  • Make sure you haven’t unwittingly covered up ventilation bricks in walls or grilles in fireplaces
  • Make sure your kitchen and bathroom both have extractor fans: these can be fitted quickly by an expert and can be combined with your lights to ensure that they are always on when the room is in use.
  • Remove draft excluders – your tenants might think the property will be colder, but a home full of condensation will be significantly chillier!

There is also the possibility however, that your tenant could have unwillingly helped the mouldy patches in the property bloom, and you may have to consider speaking to them about making some changes to their lifestyle in order to tackle the issue. These could include:

  • Get serious about drying clothes: If you believe the issue could be down to your tenant drying their wet clothes in the property, discuss this with them and maybe consider supplying a tumble drier to provide an alternative solution.
  • Keeping the heating system on a low heat, rather that sporadically on and off so as to ensure a constant warmth throughout the property
  • Properly ventilating ‘wet’ rooms such as the kitchen and bathroom

Your tenants may be unaware of how their actions are impacting on their home life, so a discussion about the issues and how you can work together to remedy them could be the most useful course of action here.

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