Mould – The Winter Problem

Winter is fast approaching and with it the perennial problem of mould –  a problem for both landlords and tenants.

There are two main reasons for mould (not definitive by any means).  One being that the fabric of the building is damaged (the landlord’s responsiblity) and secondly ; condensation mould (most likely the tenant’s responsiblity).


This is generally found in bathrooms and kitchens which have not been ventilated adequately.  It can also be found in living areas, attracted to cold surfaces such as single glazed windows, outside walls, behind furniture etc.  This kind of condensation mould can generally be attributed to life-style and mainly lack of heating and lack of ventilation.  The vast majority of rental accommodation is old, sometimes very old.  These buildings have no wall cavities and are usually single glazed and poorly insulated.

We have been encouraged to make rental accommodation air tight, by sealing up chimneys, putting upvc double glazed units in and draught proofing, so the building can no longer breathe.  The majority of landlords have complied with building regulations and provided extractors in the bathrooms, kitchens, cloakrooms and utility rooms.  However, in some cases, tenants have turned these units off, thinking they use too much electricity or are too noisy – not realising that they have been fitted for their health benefit.  With the increase in fuel prices, tenants seem to be more willing to wear extra jumpers and hats in their homes than to put the heating on – this all goes to encourage condensation mould.  Drying washing also contributes to airborne moisture unless a tumble dryer is used and extracted to the outside.

Just living in the property creates moisture, breathing (yes, breathing produces moisture), bathing, washing, steam ironing, using parafin heaters, all create moisture which will settle onto cold surfaces and could lead to black mould.  This mould is dangerous for tenants, possibly causing infections, asthma, allergies and sinusitis, for example.  If the mould is allowed to settle it can penetrate plasterwork and cause damage, which could be expensive to put right.

To prevent condensation mould, the landlord’s mantra is “heat and ventilate”.  Warm air can hold a lot more moisture than cold air.  Landlords ensure that you have adequate, working ventilation and that your tenants are encouraged to use it.  Explain that the electricity usage is minimal and the benefits of using the extractors outweigh the health problems which could occur.

It is relatively easy to clean condensation mould.  A quick wipe with a very dilute bleach solution should remove black mould from the majority of surfaces.  HG make a mould removal product which is very good too.  If you do clean in this way, please use rubber gloves and even a mask to prevent inhaling any spores.

There are also specialist companies out there who can help such as Envirovent – they may be worth a call if you are having real problems.


Landlords need to be on top of their building maintenance.  Buildings need to be water-tight – ie no leaky roofs, gutters, downpipes or drains; water needs to be prevented from entering the building other than by intended means.  Damp and mould caused by this kind of disrepair is the landlord’s responsibility to fix and maintain.  The property is the landlord’s investment and should always be fully maintained.

Hope this post helps, if you want to chat any further about mould, please give us a ring.


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