Hope someone can enlighten me on best practice for this. The flat is a solid 1950s build but is prone to condensation. All tenants are told to manage this by ventilating as much as possible however the walls still need very regular wiping . Two sets of tenants have struggled to manage this and each time we had to scrub off mould and re-paint the affected stained walls with anti-mould paint. I’ve added a clause to the contract informing the tenant it is their responsibility to ventilate and re-painting will be at their expense, is this definitely fair and legal? There is no structural issue with damp, the property is on the second floor. The local authority freeholder has no plans to add further exterior insulation. Am I obliged to provide further interior insulation myself? This will obviously be compromised if we needed access to pipes or existing chased electrical wiring. I’m quite confident that I’m doing everything correctly but need reassurance. Anyone?
How many extractor fans are there in the flat? How do the tenants dry their clothes?
I hate to suggest this but a lot of these issues can be self inflicted
What is the construction of the property?
What exterior insulation is there ?
Is this the root of the problem ?
What is the interior plaster composition
Don’t insulate walls made up of engineering brick
The need to be exposed otherwise you get mould
Our housing stock is old (>100 years)
Those that insulated get mould so I’ve avoided it
I insulate the ground and ceilings instead
Consider passive ventilation such as Envirovent.
If there are structural issues, or even lifestyle issues) a PiV will not be the solution.
I’ve used them for over a decade and they are not all they were advertised to be
Thanks for your replies. There is an extractor in the bathroom that comes in automatically with the light . The kitchen has a hood above the hob. I suspect the tenants do dry their clothes indoors.
Am I right in saying it’s the tenants responsibility to prevent mould by ventilating and wiping down walls to remove or stave off condensation?
Thanks for your reply. What is a PiV?
Positive input ventilation unit.
It was sold as the panacea to all ails 15 years ago. I reported Envirovent to trading standards for stating you would be 100% mould free or your money back
I never got my money back and was never mould free
You need to hand wash filters at least once every couple of years ( they tell you to buy them but you can handwash for nothing )
Is your extractor a humidity sensored one ? greenwood cv2gip is an excellent model and I’ve had one faulty fan since 2016
I’ve found them better than the Envirovent model
The heating and lifestyle is critical
There are so many factors that come into play
Condensation is heating ventilation insulation
You must check if the house is heated and how frequently
Houses with on off timers get more mould vs those heated with a thermostat that’s constant
If they are drying clothes indoors then they are going to get a lot of moisture in the house
I would advise them to use a dehumidifier or provide them with a condenser dryer
You can also get containers with calcium chloride salts that absorb moisture but they need to check and change the cartridge frequently ( I go in and do that myself )
You must check gutters are clear roofs have no damage and there’s no damp pouring intact , riding damp etc . Even sealants around windows need replacing as cold air leaks will contribute to mould and damp
At the end of the day, if they don’t have constant thermostatic heating on and the moisture is trapped then condensation will form because once the temperature drops below the dew point then the air loses its ability to hold any water and it all drops at once onto the nearest coldest surface, normally a window. Problem is people don’t want to pay to heat the house (understandable) but the cost of not doing so lands on you. All the wall insulation in the world won’t help if they don’t keep the temperature above the dew point and manage the moisture (humidity) level. For £39 you can buy a wireless hygrometer that tracks the temperature and relative humidity, and when it crosses the dew point, and sends all the data to your phone. You need a wireless one so that you can see how low the temperature drops during the night when everyone is asleep and the heating is off. I think landlords need to amend all contracts going forward to state that tenants agree to heat the houses to the minimum level necessary to avoid condensation, and to manage the humidity level. So you have to also give them a normal or wireless hygrometer, and make an agreement with them that they will actually use it. But at least then you have the data and the responsibility for the condensation forming is clear.
I have made it a contractual obligation to heat constantly ( advising 18 degrees as per government and NHS guidelines) and the smart meter DDU shows if they are heating houses correctly or not. I have just encountered my first problem with this. The tenant without permission changed supplier and notified me after the fact. They took out smart meters and installed old meters with no DDU so I can not see if the house is being heated properly.
Worse of all the new supplier charged c £500 per annum standing charge for their meters. Utilita don’t. I wish people would ask before they do things off their own back when they have a contract that tells them to get permission in writing.
On off heating is more expensive as the fabric of the building never heats up so the walls get really cold. That’s the biggest problem
Brilliantly informed replies. Thank you 
Am I within my rights to charge the tenant for painting walls which are stained due to them not wiping away condensation which became mould?
If you can prove they are responsible and you have a clause in your contract allowing for this
Condensation is multifaceted to win a dispute you would need an independent damp review of your property that states it’s their lifestyle causing the problem
So basically I’m on the hook for decorating costs every time a tenant leaves either mould or stained walls following scrubbing mould off?
I’ve put a clause in the contract that ‘management of condensation’ is their responsibility and cost incurred to make good will be at their expense .
If this were challenged I’ve no way of proving whether or not they managed it . Certainly if I lived there I’d be watching out for moisture and wiping down walls to prevent mould .
Lots of media around landlord not dealing with mould but what can we actually do if it’s not a structural issue?? We rely on tenants either to ventilate adequately, maintain a constant temperature above dew point, plus use dehumidifiers
I just don’t want any trouble from the authorities but it doesn’t seem reasonable that I’m expected to wear the cost or re-painting every time they leave because they didn’t prevent mould
So that’s what I mean, if you have the data to show they were causing the problem by not heating the house, then you can pass it on to them. But without the data there is really nothing you can do.
Go in and do inspections every three months
Externally and internally
Document your side for structure and their’s for lifestyle
Document everything and the advice you have given them ( inventory hive has a great template for interim inspections )
That way if it goes to dispute it can be seen that you were proactive in educating them and trying to deal with the issue
Photograph clothes on rads etc heating on the ddu
Provide them with an electric dehumidifier and or tumble dryer
At least then you did everything you can try and claim it but they will likely dispute it
The key here is taking evidence regularly to build a case in your favour
I had a similar matter with tenants not wanting to take liability years ago
I gave them a dehumidifier. They unplugged it and left it in the WC! They had a dryer that I provided. I had a PiV in situ ( filters were documented as clean and washed regularly ). They had humidity sensor fans in all the right locations .
I even helped with their gas bill ( they were students and £20 a month was no biggy)
When they disputed the deposit claims I wrote to them and reminded them everything was logged vie email contemporaneously . It shut them down before it even got to dispute with TDS.
The key here is contemporaneous documentation.
I only install piv’s for legal reasons . It’s ticking a box. Personally i think they are a waste of money but when it goes to dispute you look like you have done everything you possibly can .
Mold is not a “structural” issue, but is always a sign of underlying structural issues.
It it’s an ex local authority property it’s unlikely to have lime mortar and be a passive house which needs moisture to radiate through the walls and out.
How old is the building? What mortar is used? Is the render cracked? How many vents are there in the walls? Is there a roof problem? Do the family underneath heat their property? What’s the drainage like? Is there a problem?
If I put myself in my tenants shoes in this situation I can see a million ways of blaming the structure for the damp environment.
Cleaning the mold off and repainting is covering up the problem, not fixing it.
If it’s fixed you have a more attractive environment for tenants to live in, can charge more and prevent costs of maintenance further down the road.