Mould with a Covid Twist?

Lack of ventilation. Tenants either understand it, or they just don't get it. Many of us will have had condensation-free properties for several tenancies then suddenly a mould complaint.

An extreme solution would be to commission a surveyor's opinion, on the basis that if its a defect, you pay, and if its due ventilation lack, they pay.

I expect you have extractor fans. Ideally the tenants could be persuaded to keep them on as well as keeping the windows on the vent setting.

We have seen quite a large increase in this area this winter. Especially if the residents are working from home and to be fair by and large it’s usually a lack of knowledge rather than being malicious. Our company policy is to provide them with a dehumidifier (of which we keep several in stock) for 2-3 weeks and once we can establish that this alleviates the issue we encourage them to buy their own with a large subsidy from us and it’s theirs to keep. This is a much cheaper option than the repairs and also wasting our time arguing. In the majority of cases it’s been a very successful outcome but I will admit there are some people who seem happy to live in squalor. If this does happen then we document the issue and report the matter to our local private sector housing department, just to cover ourselves as we do have a duty of care

This recently happened to me. A ground floor flat, let several times without any condensation issue, recently became badly affected by mould spores. I explained the flat wasn't ‘damp’ as such but the issue was condensation - to no avail. I received a letter from the Council housing officer requesting I rectify the building issues. There were none. It was how it was occupied that was the problem. The combination of being a sole occupier who worked 12 hour shifts (so it was left cool for long periods) in a ground floor flat (higher floors benefit from heating below) and not ventilating properly was the issue.

There is a strong possibility it is due to condensation. For what it would cost I wouldn’t hesitate in installing a Positive Input Ventilation system (PIV). It is a whole house air ventilation system that works by drawing in fresh air into a property from outside lowing the humidity levels inside. These can be either installed in a loft space or on a wall in a flat or apartment. They are relatively cheap to buy around £350.00 plus fitting. I had similar situation, we cleaned all the mold off with bleach, installed the PIV system and it worked instantly. It will also clear your condensation problem. Below is a previous thread that you may find useful. Good luck.
https://www.property118.com/now-is-a-good-time-for-landlords-to-carry-out-mid-tenancy-inspections/

We have a property that used to be a real problem. Black mould would appear every year requiring treatment and re - decoration in both bedrooms. I took the following actions: I supplied the tenants with a de-humidifier, I installed vents in the UPVC double glazing and I even tried re - decorating with anti - mould bathroom paints. The tenants (to their credit) stopped using an old tumble dryer which they vented out through a window and they bought a condensing tumble dryer. But, still the problem persisted. The game-changer was the installation of a PIV (Positive input ventilation) system in the loft. This system pumps the dry air from the attic into the upstairs landing, ventilating the whole property. The unit cost about £320 and the tenant and I fitted it into the loft together (he was a qualified electrician). A great example of a tenant and a landlord working together to solve a problem! Since then, we have had no condensation or mould in the house at all. A great result and the best £320 that I have spent on a property! I have now installed an identical system into my own house. Even though we get very little condensation; it's still good to keep a house well - ventilated and fresh, especially in the coldest part of winter. The tenant has since moved on, so, when my agent drew up a new tenancy agreement I insisted that a special clause should be that the system is turned on every October and turned off every April. Also that the tenant himself/herself is liable for the very small cost of the electricity to run the unit. It is a Nuaire Drimaster.

The difficult problem with condensation, is trying to explain to tenants how to avoid, by the contradictory requirements of heat and ventilation. I've battled for years with this problem but appear to be winning. I was interested to read of the PIV system but my properties are probably too big as they are HMO's, four levels high.

I have the problem of mould here today and gone tomorrow but my general rule is, if it appears two or three times in the same place I insulate. These places are usually on outer walls especially around windows. I've insulated the outer walls of whole rooms, and when I refurbished I highly insulated my kitchen, and dining area which got rid of all my condensation problems, and to a standard that my tenants do not always have to heat this area. I've even moved my bathrooms to places where they have less outside walls.

I have supplied dehumidifiers but they get moved around and my tenants rarely bother to use them. But one of my best things I did was to us good quality Passyfiers. They let fresh air in without letting out heated air.

As I think I have done my bit to solve these problems I have now put in the lease that they are responsible to wipe mould with bleach or wipe condensation which makes them realise they have a part to play in solving this problem

Tenants drying their washing on the radiators can be the cause of the problem, especially if they have young children and have to do multiple washes each day.
I provide a dehumidifier in all my old-style houses, but tenants rarely use them. There is a good leaflet available on the NRLA website that you can print off and hand to tenants, which explains how damp is caused. Search for Condensation Factsheet

Thanks for all the helpful comments,they have now had a burst pipe on the coldest night of the year so far ,despite their claims that "the radiator is always on in the the bathroom".
Hopefully they have realised they must keep the flat at a reasonable temperature, but only time will tell.
Apparently, I am not their Dad but blooming well feel like it!

A bit late to the party on this one but the link below may be useful-I refer my tenants to it if we have a damp problem that's really interstitial condensation. The fact its from the local borough council seems to make it carry a bit more weight.
https://www.reading.gov.uk/housing/private-renting/repairs-and-maintenance/damp-and-mould-in-the-home/