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Dealing with Damp Issues in a Rental Property

Damp is a common problem in the UK’s rental housing stock. Many landlords can’t or decide not to invest in their properties, leaving tenants to live in cold, damp homes. In areas where demand for rental housing outstrips supply, rogue landlords often get away with housing tenants in sub-standard accommodation. Tenants are often too afraid to complain. 

Short-term damp issues are sometimes unavoidable, such as when there has been localised flooding. Damp can also be a problem in poorly ventilated homes, which is often the tenant’s fault. Damp is preventable if regular maintenance is carried out and an older property is properly renovated and ventilated.

In this guide, we are going to look at damp issues in more detail, examining the causes, how to fix the problem, who’s responsible, and more.


Damp in Older Properties

Homes in the private rental sector are usually older properties, the majority of them terraced houses. 43% of homes built in Wales, 35% in England, and 39% in Scotland were built pre-1919. This means they are far more likely to have damp issues than modern homes built to different specifications.

Energy Efficiency and Damp Issues

Since cold homes are often damp homes, there is a strong link between energy efficiency and damp problems.

The UK English Housing Survey data for the year ending 2017 and published in 2019 showed that 25% of rental properties in England, 26% of properties in Scotland, and 20% of Welsh properties fell into Band E and below for energy efficiency.

Whilst the Minimum Energy Efficiency Standard (MEES) regulations have forced landlords with properties in Band F and below to improve them or sell up, there are still a lot of rental properties in the private rental sector with damp issues.

Health Problems Caused by Living in a Damp Property

People living in damp homes are more likely to have health problems, as it can affect the immune system. The elderly, the very young, people with pre-existing respiratory issues, and immunocompromised tenants are particularly at risk.

The main problem with damp homes is that in the long-term it leads to mould growth. An NHS study found that people living in damp homes were two times as likely to have respiratory health issues such as asthma, respiratory infections, and allergic rhinitis. Damp issues can also cause skin irritation such as eczema. This report by the World Health Organisation (WHO) goes into more detail.

Since cold and damp are often found together, those living in these conditions are also at an increased risk of rheumatoid conditions and cardiovascular health problems. People with cold, damp houses are far more likely to catch the flu in winter, take longer to recover and suffer from long-term complications.  

Don’t underestimate the effect on a tenant’s mental health either. A 2017 research study by Shelter found that 10% of tenants had experienced problems with their mental health because of poor quality housing, which costs the NHS around £1.4 billion a year.

Causes of Damp

In simple terms, damp problems are essentially caused by too much moisture in the property, which can’t escape.

In the days before central heating and double-glazed windows, homes had open fireplaces. They didn’t need damp-proof courses because the air blowing in through gaps around doors and windows, or through the floorboards, took any residual moisture away up the chimney.

Blocking up chimneys, putting carpets down, installing double-glazing and UPVC doors has eliminated most of the natural ventilation in older properties and newer properties are designed to be hermetically sealed boxes. The downside to this is poor ventilation and problems with excess moisture in the atmosphere.

Some causes of damp in rental properties are obvious, others less so.

Penetrating Damp

Penetrating damp is where moisture penetrates through the walls from the outside. The most common cause of penetrating damp is an issue with the building itself, such as crumbling mortar or failed render. Homes in coastal locations where there is a lot of salt and moisture in the air can also be prone to penetrating damp.

Another common cause is a leaky gutter, which is easily rectified. Gutters that are too small can also increase the chances of water streaming down the wall each time it rains.

Old cast-iron waste pipes can cause penetrating damp issues when they crack. If you have a damp problem in the vicinity of a soil pipe, rule this out before looking for other problems.

Dry rot is a serious damp-related issue whereby mould spores germinate on timber. It is a complication of penetrating damp issues caused by defective masonry and can destroy floor joists and other timber in a home. Unlike wet rot, dry rot fungi can spread through masonry. If left untreated, dry rot can cause serious structural damage.

Rising Damp

Rising damp is common in older properties, particularly those built on low-lying areas such as flood plains. As already mentioned, damp proof courses were not needed in the ‘olden days’, as homes were naturally well ventilated. Today, most have had UPVC windows and doors installed and fireplaces removed as part of a modernisation process because tenants want draft-free, secure homes. Walls are painted using modern vinyl paints, which are essentially plastic. They can’t ‘breathe’. Cement mortar used to repoint older homes or cement render can also trap moisture in the walls, which makes matters worse.

Natural moisture rising from the ground has nowhere to go, so it lingers in the brickwork and causes damp.

Signs a property has rising damp include:

  1. Damp patches on ground floor walls, up to a height of approximately one metre

  2. Salt deposits on walls

  3. Crumbling or discoloured gypsum plaster at ground level

  4. Blistered paint

  5. Peeling wallpaper

  6. Mould and mildew on walls

  7. Warped skirting boards

  8. Rotten floorboards and timber joists

  9. A musty smell

A damp proof course (DPC) is designed to prevent water travelling up from the ground and through the walls. In modern homes, a plastic membrane is used. Prior to the invention of plastic, slate was often used. Period homes may not have a DPC at all unless one has been added retrospectively.

A DPC can be bridged if the ground is raised up, such as when a new patio is constructed higher than the existing DPC, or a new wall is built that abuts the house. External render can also overlap the DPC, allowing moisture to move up the walls. Replacing a suspended timber floor with a solid floor can affect a DPC in older properties.


Condensation builds up when water in the atmosphere condenses against cold surfaces and can’t escape. Moisture arises from activities such as bathing, showering, cooking, and drying damp clothes on radiators.

The average human exhales and perspires around 40g of water every night and 70g per hour when sitting at a desk. In a home shared by four adults, that’s a lot of moisture.

If that moisture can’t escape, it will condense on colder exterior walls and windows, leading to damp and mould issues.

Signs a property has condensation issues include:

  1. Moisture streaming down the inside of windows

  2. Water puddles on windowsills

  3. Mould and mildew growth on walls, ceilings, tiles, grout, bathroom sealant, skirting boards

  4. A musty smell

Construction Damp

Sometimes, problems are caused by the way the property was constructed or a design defect. For example, the property could have a cellar that floods each time the water table rises. In this instance, as long as the flooding is not causing any damage to the structure of the building or making the tenants ill, the landlord isn’t responsible for fixing the problem.

Damp Caused by Leaks

Leaking pipes and failing cast-iron waste pipes in older properties may be a hidden source of damp issues. Even tiny leaks can cause catastrophic damage in time. The water keeps on leaking, so the moisture has no chance to escape. Eventually, it seeps into other areas.

Bathroom leaks can cause damp issues in adjoining rooms or the room below. Inadequate grouting in showers may cause water to seep through, creating a damp patch on the other side of the wall. Damaged sealant around baths and shower trays can be a problem. Older plumbing may start to leak around joints, or if some of the pipework is cast-iron, corrosion can lead to leaks inside walls.

Leaking gutters and downpipes are another source of damp. A small crack in a gutter can cause significant damage to an interior wall when the water begins flooding down the brickwork each time it rains. If it isn’t fixed, the plaster can’t dry out and you have a damp problem. Leaky gutters can also channel water into the roof space, which will seep through into rooms below.

Don’t forget about leaking roofs, too. One slipped tile will cause a lot of damage if rain finds a way in for extended periods. Damaged lead flashing around chimney stacks will let water in and cause damp patches.

Poorly fitting windows, dormers, and doors also let water in, which leads to damp in the affected area.

Note that leaks not dealt with in a timely manner can lead to infestations of dry rot, which as we have already stated, are serious.

Damp Caused by Inadequate Heating

Not heating a property enough can soon lead to damp problems once condensation begins to build up on windows and exterior facing walls. Unfortunately, it is a tough nut to crack, as you can’t police your properties heating 24/7.

Be aware that tenants looking to save money may try to do so by not switching the heating on as often. It’s important to carry out regular property inspections, which will help you spot problems before they become major issues.

Damp in new Build Properties

Water is used in many of the materials needed to build a house, from cement, mortar, and concrete, to plaster and grout. If you have purchased a new-build property, it’s important to be aware of the potential for damp. It takes months for a new build property to dry out, and it will take even longer if the build is completed in the depths of winter.

Allow at least 12 months for the property to fully dry out. The house must be well ventilated and adequately heated during this time. If necessary, provide your tenants with a dehumidifier to remove excess moisture from the air.

Structural problems and inferior workmanship can cause serious damp issues in new build properties. This includes poorly fitted extractor fans venting into wall recesses, no recessed pointing on exposed walls, etc. If the problem is severe, it is worth hiring a surveyor to identify the root cause, which will give you greater leverage in the event of you making a claim for compensation from the developer.


If the property has been flooded, either by a serious leak or an environmental disaster, it will have damp issues unless it is allowed to dry out. Flood damage is normally covered by landlord buildings insurance, so follow their guidance. If the flood renovation work is not done correctly, timbers may be attacked by dry rot and other damp-related issues.

Fixing Damp Properties

Fixing damp problems is largely a case of undertaking property maintenance or spending some cash on renovating an older property. Gutters don’t fix themselves and if a house has rising damp, it won’t get better if you ignore the problem for a few months.

Always deal with leaks as soon as the tenant notifies you of a problem. The longer water is allowed to drip, trickle, or flow out of a faulty pipe joint, toilet, or storage tank, the more damage the property will sustain.

Not all leaks are evident. Sometimes water seeps out of a leaking pipe hidden under a floor or inside a wall cavity. When this happens, the tenant might not know there is an issue. Be vigilant for unexplained damp patches on walls, ceilings, or floors. Always investigate as soon as possible.

Note that if the central heating boiler is losing pressure faster than normal, it is a red flag there is a leak somewhere in the system.

More serious damp issues such as penetrating damp or rising damp require the services of a professional. The most common way to deal with a case of rising damp is to hack off all the plaster up to approximately 1m, inject a chemical damp proof course into the brickwork, apply a waterproof cement render to the wall, and finish off with a layer of plaster. The exact method used to treat the damp will depend on how extensive and serious the problem is.

It’s a good idea to have a damp survey done to verify the problem is indeed rising damp rather than penetrating damp or a hidden leak. Damp problems in older properties are often complex and not necessarily caused by one thing.

Always use a reputable contractor to resolve damp issues in a rental property. Not doing so may mean that the job isn’t completed up to standard and that the walls only stay dry for a short while.

Bear in mind that damp-proofing remedial work is noisy, dirty, and you can’t expect your tenants to live in the property while the work is being carried out. It is best to carry out this kind of job between tenancies. It will take time for the walls to dry out before you can redecorate – potentially several months if the work is done over winter and the house isn’t heated.

If the property is occupied, factor in the cost of providing your tenants with alternative accommodation, and possibly storage costs, as furniture and personal items will need to be moved out of the way in downstairs rooms.

The law and Damp in Rental Properties

Living with damp isn’t pleasant. Damp homes smell, and before long, soft furnishings, clothes, carpets and curtains smell too. If the problem isn’t fixed, mould and mildew appear.

The first recourse for tenants is to report damp problems to the landlord. If the landlord doesn’t act or they don’t feel comfortable contacting them, tenants can get in touch with their local Environmental Health Department.

The Homes (Fitness for Human Habitation) Act 2018

If a home is horribly damp, it is arguably unfit for human habitation. Under section 10 of The Homes (Fitness for Human Habitation) Act 2018, tenants can take the landlord to court if their rental home is riddled with damp. This means landlords have an obligation to ensure their rental properties are free from significant damp throughout a tenancy.

Once a tenant has reported you for not fixing a damp issue, you must reply within 14 days to tell the tenant how you are going to fix the problem. What you can’t do is serve an eviction notice to avoid the cost of having a new damp proof course installed – that’s known as a retaliatory eviction and it’s illegal. If you do try to evict a tenant within six months of them reporting a problem, you may have to pay compensation on top of the cost of any repairs needed.


Damp problems are a statutory nuisance under the Housing Health and Safety Rating System (HHSRS). If landlords don’t fix the problem, the local authority can force them to take action.

Landlord and Tenant Act 1985

Structural problems that could cause damp issues are also covered by Section 11 of the Landlord and Tenant Act 1985.

Is the Landlord Responsible for Fixing Damp Problems?

When damp is caused by structural problems such as improper cavity wall insulation, a leaking roof, rising damp, etc., then the landlord is responsible for rectifying the problem. The tenant can take legal action against you, and the court can order you to take remedial action, as well as award the tenant compensation.

In a crackdown on rogue landlords in Greenwich last year, five HMO landlords were each fined £5,000 for failing to licence their damp, overcrowded properties.

Even if you believe the tenant bears some responsibility for the problem, it’s still prudent to act promptly to find a way to resolve the damp. If you don’t know the source of the problem, have a damp survey carried out or call in a plumber to try and locate a hidden leak in the plumbing system. The more effort you make to resolve the damp, the harder it will be for the tenant to persuade the court you are a rogue landlord.

When is the Tenant at-Fault for Damp Issues?

Condensation is often the primary cause of damp. Tenants are responsible for the problem if they never open windows in bathrooms and kitchens, dry laundry on radiators, and fail to heat the property to an adequate level. Unfortunately, it is hard to prove when the tenant is at fault for damp issues.

It’s wise to offer tenants some guidance at the start of the tenancy. Remind them to ventilate rooms daily and if you spot laundry on radiators during a property inspection, warn them this could lead to damp and mould problems.

Can a Landlord Hold on to a Deposit Because of Damp?

The landlord can potentially withhold some or all of a tenant’s deposit to cover the cost of fixing damp-related problems if they believe the tenant is at fault.

Without evidence to show the property was in mint condition at the start of the tenancy and the tenant is at fault because they never opened a window and dried laundry on the radiators every day, an arbitration will probably rule in favour of the tenant in the event of a deposit dispute.

It is sensible to carry out detailed property inspections and take photos to show the property was in good condition before the tenant moved in. Even if you do this, you won’t have a leg to stand on if the damp is caused by a structural issue or building defect such as rising damp. You’re also in a sticky corner if the tenant notified you of a problem and you didn’t lift a finger to resolve it.

Preventing Damp

Resolving structural problems and keeping on top of maintenance issues is the best way to prevent damp from raising its ugly head. If you buy an older property, be mindful of the problems caused by rising damp and penetrating damp. Fixing problems such as leaking gutters or pipes quickly is the best way to avoid long-term damp issues.

Other methods to reduce the risk of damp affecting your rental property include:

  1. If you install UPVC windows, make sure they are fitted with trickle vents, and ask tenants to use them when windows are closed.

  2. Fit a decent extractor fan in the bathroom.

  3. Don’t remove air bricks – cover them with a plastic grill to control airflow if necessary.

  4. Remind tenants to open windows for at least 20 minutes each day, even when it’s cold.

  5. If condensation is a problem, provide a dehumidifier to remove some of the excess moisture from the air.

  6. If you renovate an older property, use breathable lime plaster and paint suitable for this type of plaster, such as clay-based or silicate paint; this allows residual moisture in the walls to evaporate without damaging the substrate.

  7. High-tech solutions like mechanical ventilation heat recovery (MVHR) systems are a sure-fire way to save heat and reduce condensation, but they are expensive to retrofit in existing properties.

Unfortunately, preventing damp isn’t always straightforward. Poor ventilation is a major cause of damp, but modern properties are designed with very little natural ventilation unless windows are opened. Older properties have more natural ventilation, but upgrading them with UPVC windows, a new central heating system, and sealing up airbricks can create problems due to poor levels of passive ventilation.

And Finally…

Stay on top of your maintenance issues and be vigilant for damp problems. If a tenant says there is a problem, head on over and inspect the area yourself. Be quick to call in the experts if you believe there is an underlying issue causing the damp. Property is an expensive asset and it’s wise to take care of it. Otherwise, you could end up suffering from capital depreciation. And remember, a well-maintained property is a lot easier to sell than one riddled with damp and crumbling walls!

Congratulations, you have reached the end of this report. We hope you have found it useful and are now better educated on the many delights of damp.

Let us know if any of your properties have had or are suffering from damp issues. How have you tackled the problem? Has it caused issues with tenants? You can reach out to us on Twitter or Facebook. We’d love to hear from you!

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