As a landlord, the issue of damp can be a constant headache, especially during the colder months with tenants complaining about wet windows, musty smells and damp walls. Although damp can be caused by a building fault or, in some rare cases, rising damp, the most common cause is condensation.

In situations where condensation is the root cause of the damp, your tenants have a larger impact than they may realise. There are also measures that you can take as a landlord to adequately ventilate your property to reduce condensation. The costs can be considerably less than you might think.

This guide looks at affordable, preventative methods to reduce condensation and the risk of damp, as well as methods to restore a property that has been hit by damp and mould.

Damp: Landlord responsibilities 

There are three causes of damp:

Penetrating damp: Penetrating damp is caused by water passing through walls and is usually caused by building faults and structural problems, such as faulty guttering, leaking pipes, damaged roofs or issues with the exterior walls. 

It’s advisable that when preparing the property for rental you check for any building faults.

Condensation: Condensation occurs when warm moist air condenses on cold surfaces such as walls and windows. This is particularly common in rooms such as kitchens and bathrooms where high levels of moisture is created. However condensation quite often occurs in bedrooms during the night due to the moisture created by the occupants.

Rising damp: Rising damp is caused by ground water moving up through a wall. This is usually stopped by a damp proof course (DPC) however when the DPC is bridged, damaged or non-existent it can allow water rise up the masonry. Read our guide for more on diagnosing and treating rising damp.

Dampness is the responsibility of the landlord if it is due to building faults such as the walls or roof, structural defects such as inadequate ventilation, poor insulation or faulty heating. 

How does condensation cause damp? 

Condensation occurs when moist air comes into contact with colder surfaces like windows and outside walls. Warm air in your home holds more moisture than cold air, as it comes into contact with cold surfaces, it deposits the moisture. This often results in wet walls that can lead to black mould growing.

This is also a common occurrence in places where there is limited air flow such as behind wardrobes, headboards & sofas.

Reducing condensation with ventilation systems 

Condensation can be controlled through preventative methods such as improving ventilation in the property. There are a variety of ventilation methods and systems that can focus on single problem rooms or be installed to ventilate whole homes.

It’s important to point out that there are several things that your tenants can and should be doing to ventilate the property. For more on this click here:

Low-cost ventilation systems – Perma-Vent 

The most affordable ventilation system is the Perma-Vent. These vents are environmentally friendly and contain no moving parts - meaning there is no maintenance required. The Perma-Vent is a form of passive ventilation and allows warm moist air carrying moisture to escape outside the building while encouraging airflow through your property.

Perma-Vents are easy to install and can be installed in as many rooms as required, they can also be installed in kitchens and bathrooms however should not take the place of a good quality mechanical extraction fan. The unit contains a vapour permeable membrane, which allows vapour to leave the building without allowing a draught back inside, ensuring your tenant’s home stays draft free.

Benefits of the Perma-Vent:

  • Most affordable ventilation system – it’s less than £20 excluding VAT
  • Easy to install
  • Maintenance free
  • Environmentally friendly
  • Used by professionals

Perma Vent Condensation Control Air Vent

Heat recovery ventilation systems - Kair Heat Recovery Unit

The Kair Heat Recovery Ventilator continually extracts moist air from the property and replaces it with fresh air from outside. During times of increased moisture, such as during showering or cooking, the unit automatically switches to boost mode. Once the moisture levels have returned to normal, the unit automatically returns to standard mode, making the Kair Unit much more economical than a standard extraction ventilation unit.

The system has an in-built heat exchange unit to ensure that as the moist internal air is drawn out, it passes over a heat exchanger, which traps the heat in order to warm the incoming fresh air. This makes it energy efficient, keeping the property warm.

Benefits of the Kair Heat Recovery Unit:

  • Easy to install
  • Low running costs
  • Dramatically improves indoor air quality
  • Meets IEE, SELV and Building Regulation requirements
  • Guaranteed for 5 years 

For more information see our Kair Heat Recovery Unit Guide.

Kair Heat Recovery Room Ventilator

Whole house ventilation systems - Nuaire Drimaster ECO Heat Unit 

The Drimaster Eco Unit is a low-energy, whole-house ventilation system. It uses a Positive Input Ventilation (PIV) system which continuously pulls fresh, filtered air into the home at a continuous rate.

PIV systems are installed in the loft and draw air through the filters and returns fresh air into the property via a diffuser located in the hallway ceiling. A qualified electrician will be required to wire the unit into the mains power supply however additional sensors and controls can be installed by you or a handyman.

Benefits of the Nuaire Drimaste ECO PIV Unit:

  • Cures condensation & damp throughout the whole property*
  • Most popular solution with landlords
  • Easy to install
  • Extremely energy efficient
  • Low maintenance
  • 7 year warranty
  • Meets part F & L of Building Regulations

*Will not work in properties with fire doors with seals.

Nuaire Drimaster Eco Heat PIV System

Dealing with damp & mould 

If damp and mould have been a problem in a property you own or manage, you will need to fix this before the house is put back on to the rental market. Tenants are becoming increasingly savvy when looking for evidence of damp before signing up for a property, so you will want to ensure that the problem has been fully eradicated.

Once you have dealt with the root cause of the damp, you can look at making good. You may well have installed ventilation units as outlined above to prevent issues with condensation. Anti-mould products are ideal for making good and are both affordable and simple to use.

Use Anti-Mould Wash to remove black mould, fungi, mildew and algae from effected surfaces including window frames, skirting boards, tiles and painted walls.

Once the surfaces are clean and mould free, you can use Anti-Mould Paint to prevent the mould from coming back, even in areas of persistent condensation. This cost-effective method is easy to use and also comes with a five-year manufacturer’s guarantee. Damp proof paint can also be used to create an impermeable membrane against water ingress.

Permagard have also put together an anti-mould kit that contains a mould wash concentrate, anti-mould paint additive as well as all you need to safely apply the products.   


Ways tenants can reduce condensation

There are many things that we do every day that can cause an increase in condensation and ultimately result in damp. It is advisable to include information within the tenancy agreement around what tenants themselves should and shouldn’t do in order to reduce this risk.

Lifestyle issues to advise your tenants about:

  • Use the extractor fan in the kitchen when cooking
  • Cover pans when cooking
  • Avoid drying clothes indoors, especially on radiators
  • Open windows, in particular at opposite sides of the property to allow for cross ventilation
  • Keep heating on constantly at a low temperature throughout the colder months
  • Keep bathroom and kitchen doors shut when showering or cooking
  • Don’t block air vents or ventilation points

These may seem too simple to work but trust us, they work!

By putting these simple and affordable preventative and corrective measures in place you can say goodbye to unhappy tenants.

Permagard: The condensation experts 

Do you have a question about reducing condensation or removing mould from your rental property? Contact us on 0117 982 3282 and our damp proofing experts will be happy to help you find a solution.

Visit our Condensation Control section for more information and the products available to help reduce condensation in the home.