This is not an enquiry into a landlord's personal hygiene.
It is an increasing problem for landlords. Many of them have resulted from some of the ‘improvements’ in building technology of recent years which have themselves contributed to increased problems with mould and damp.
I have had a recent case myself of a ground floor maisonette which I bought and improved and which had no apparent signs of damp but then went on to develop a significant mould problem. My experience highlights several factors that landlords should be aware of which can contribute to condensation, damp and ultimately mould.
The 1960s maisonette was purchased from an old lady who because she was not working was present at the property during the day as well as in the evenings. It had electric storage heaters and UPVC windows. The latter are frequently seen by landlords as a plus point as they require less maintenance work.
After purchase I set about the upgrading of the property which included installing gas central heating for the first time. The property was initially let to a couple during the summer months without a hitch. Then two young female sharers moved in.
This is when the mould problems started. The damp and mould was located low down in a bedroom on one particular wall but then started to spread. My initial concerns were that the property was suffering from rising damp. I got a building surveyor to check out the problem.
Rising damp is caused when moisture is drawn up through permeable building materials through capillary action. It occurs at the base of a building where moisture is drawn from the ground through the brick work and then appears inside as damp patches located low down within the building. He concluded that this was not the problem given that the damp proof course was still in tact and the patches started over 1m above ground level. One metre being the approximate maximum height that water can rise through capillary action because of the counter effects of gravity.
He concluded therefore that it must be condensation. I was initially quite relieved about this figuring that condensation was a much easier to solve problem to solve than rising damp.
What is condensation?
Condensation occurs where moist warm air comes into contact with colder dryer air, or a surface which is at a lower temperature. The result is that moisture which is naturally contained in the air then turns from an invisible gas back into a liquid i.e. water.
Air contains water vapour in varying quantities; its capacity to do so is related to its temperature – warm air holds more moisture than cold air. When moist air comes into contact with either colder air or a colder surface, the air is unable to retain the same amount of moisture and the water is released to form condensation.
Moisture in the air comes from a number of sources. In for example a 5 person household there is about 10kg or 10 litres of water put into the air every day (without taking into account any heating) i.e.
Breathing (asleep) 0.3 kg
Breathing (awake) 0.85 kg
Cooking 3 kg
Personal washing 1 kg
Washing a drying clothes 5.5 kg
Moisture can also be drawn from the structure of the building from below the floor or the walls/ceilings into the air. Problems with the structure of the building due to its’ method of original construction or as a result of structural failures can mean that its moisture content is unnecessarily high.
My damp patches!
I return to my condensation problem. I initially thought that there would be a quick resolution of what seemed like a straight forward problem. My first thoughts were to ensure the ventilation of the areas of highest moisture generation to reduce the overall levels of water vapour. The property was occupied by two young female teachers who at a guess were probably showering at least once a day. Showers are great emitters of water vapour therefore my first action was to install an extractor fan. This I did and for a while the problem seemed to be fixed. Within a few weeks there was another call from the tenant informing me that the problem was getting bad again. They had previously discussed me providing a dehumidifier which I initially resisted. Having exhausted one avenue of attack I decided to try this as a possible solution. This approach initially showed some promise but again the problem returned. Now we were well into the winter which is the worst time of year for condensation. This is because the tenants are reluctant to open windows to ventilate, especially whilst the central heating is on. The result is warm moist air is generated in areas like kitchens and bathrooms which then penetrates to colder parts of the building resulting in condensation and associated problems in these areas. Following further investigation into my options, I contacted a specialist company for a second opinion. They reiterated the diagnosis as condensation being the primary cause of the mould and suggested that I install a passive air vent to improve the air flow.
Why the problem?
The question that kept hitting me during this time was why this problem had started to occur when the previous owner had lived at the property for years without any sign of damp or mould. I had been a witness to this having visited the property on several occasions.
The causes & the lessons for landlords
My experience has allowed me to conclude several things. Firstly, it is clear that there is no single reason for the condensation. As is the case with building defects there are frequently a number of contributory factors:
1. The installation of central heating. The replacement with storage heaters with a more powerful heating system such as gas central heating can potential exacerbate any condensation problem. This is because it will lift the average temperature in some parts of the property which means more water vapour can be carried in the air. This means that when the cold part of the structure is reached by this moist air. Then even greater quantities of condensation are laid down than would have been possible with a less powerful heating system.
2. Intensity of occupation. One objective of any landlord is to maximise their rental income. This can often be achieved by letting to a number of sharers. In my case the numbers of people living in the property doubled. This means twice the amount of moisture was coming from breathing, showering, cooking, cleaning, etc.
3. Nature of occupation. The other significant change was the way the property was inhabited. When the little old lady was there, because she was there during the day she would leave the windows open whilst she cooked, cleaned just to air the property. The two professionals were out during the day and when they returned it was often dark and cold. The result is that no ventilation of the property occurred.
The fact that the property had UPVC windows exacerbated the problem. Whilst sealed double glazing undoubtedly improves the heat retaining properties of the building it also turns the buildings into a sealed vessel preventing any exchange of air. This is particularly the case with more modern building which were designed to higher insulation standards than older say Victorian properties.
What can landlords do to prevent a condensation problem?
My experience has highlighted a number of things that landlords should ensure if they want to avoid condensation and mould becoming a problem:
Lawyers would always highlight the need for landlords to have an appropriate clause in the tenancy agreement to safeguard their property. However, how would you word it, how would a landlord monitor and prove non performance against the standards set our in the clause? I would suggest that it would be virtually impossible. The landlord however does have an obligation under section 11 of the Landlord and Tenant Act 1985 to repair the property
The realities are that many professional tenants exist in a world of air conditioning – in their car at work during their socialising in bars and restaurants. Therefore, frequently the concept of opening windows is alien to them. This is particularly true when occupying a house or ground floor apartment where security issues also come into play. Just as my professional tenants found it impractical to ventilate the property on a regular basis, you will struggle to encourage this behaviour even through clauses in your tenancy agreement
The real solutions are therefore going to be structural. Firstly, landlords as I have done need to appreciate that UPVC is not the panacea to all your window requirements. In buying a property with UPVC particularly one that was upgraded, you will need to examine what kind of ventilation exists and where it is. Even modern properties where UPVC glazing is accompanied with trickle vents to allow ventilation these can be closed meaning that they will only be effective if the tenant uses them. If the ventilation is not adequate then you will need to add in some kind of passive ventilation to ensure adequate air flow and water vapour removal. Otherwise condensation and mould growth could become a problem. The best way to do this is to insert air bricks. These can be covered with a plastic grill to allow the occupiers to control the amount of air flow. However, the landord will have to ensure that the tenants use them correctly and do not keep them closed. The fail safe option for landlords is to use the basic variety.
For those landlords keen to reduce the heat loss to the property the high tech solution are mechanically powered ventilation systems. .However, they may save your tenants heat but they may not necessarily save the planet given that they use power all the time that they are on. They will also be more expensive than basic air bricks and once installed require maintenance every two years.
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