Did Installing Underfloor Heating Help with Condensation and Mould?

[Mercurial123]

I bought a ground floor Victorian flat last year which was fully refurbished. It's on a hill and a ten minute walk to the sea if that makes a difference.

The survey recommended putting air vents at the front of the property for air circulation to prevent damp, which I did. The builder said he found condensation when installing them, and after a week or so, the tenants are complaining of mould and condensation, which isn't getting better with a humidifier.

I was reading underfloor heating may solve the condensation issue. I plan to move in the flat in the next two years, so don't mind the expense and obviously want my tenants to have a decent place to live. Has one installed it, and did it prevent condensation?

Also, what else could the issue be? They say the property is well ventilated, so air is circulating.

The builder will be trying to find out the issue sometime this week.

TIA

I think the first thing you need to do is work out where the damp and mould is coming from. Underfloor heating won’t help with a leak, dodgy gutters or a roof issue. It may be that the current vents aren’t working properly and need more time before the effect is seen. Do you know if your tenants are heating and ventilating the house properly at the moment? The other (related) thing is that the running costs of underfloor heating can be very high (depends whether you go for electric or water based)- would you be paying bills as well as installation while the tenants are in occupation? If not I’d probably think again- there’s no point installing it if your tenants can never afford to turn it on!

Also if you’ve only just bought the place, was there anything in the survey or SPIF? And do the other flats in the same building have damp?

we are having a mould problem in our flat and think it’s a problem with the build. I was interested to hear you had ventilation bricks put in was this an expensive thing to have done? we are thinking of paying a damp company to come and do a survey to find out what the problem is before we spend money. Be a shame to pay for flooring and it doesn’t help

@Heronwatcher thank you. At the moment getting the underfloor heating is just a thought. I read it wasn't too expensive to heat the flat but that was from the companies that install it so probably best not to rely on that information. I would find the source of mould and condensation first if I decide to go ahead.

The flat was fully renovated two years ago, and it was tanked. This could be the issue as it covers up damp but doesn't find the source.

Tenants are saying they are ventilating and heating the house, but I'm overseas and receiving information from the letting agents.

@wishmyhousetidy thank you. It cost around £350 for two ventilation bricks. I'm waiting to see what the builder says when they visit in the next few days.

I am also considering getting damp specialists out to do thermal imaging to see where the issue is.

Be careful with damp specialists. They often prescribe injection damp proof courses and tanking the bottom of the walls which generally can some times cover up the issue but often longer term makes the problem worse. It is much easier to sort out damp problems of you are living in the property.

First thing is to check gutters to make sure they aren't blocked and see where the damp proof course is and whether the external ground level needs lowering. Next check for external drains to make sure they aren't leaking, then check internal drains and pipework.

I wouldn’t spend money on this before doing things like making sure the dehumidifier is a really good one and is on all the time, and that the property is heated well - what’s heated well to one person isn’t to another. We have a really damp house, I’m not sure why because it’s a standard semi but at one point we had water dripping down from the lights in our bedroom! We had air vents put in, roof refelted for breathable felt, etc etc. We have finally cracked it after realising we really do need the heating on at about 19 degrees most of the time when it’s cold (not at night but about 6 -7 hours a day, costs a fortune) and we run a £250 dehumidifier 12 hours a day.

When we had a 4 bed in London we never, ever had issues with condensation and damp. Ever. It’s very frustrating.

I’d be annoyed if I’d spent more money on underfloor heating.

Thanks, I agree I don't trust damp "specialists" either.

I have a builder visiting the property in the next few days and a surveyor who will do thermal imaging so between them I hope the issue can be resolved.

XRays thank you, that's interesting. I am waiting to find out what dehumidifier they are using. I've been told they are heating and ventilating the flat, but who knows.

The thermal imaging should give answers. I'm hoping it's the tenants causing the issue as that's an easier fix.

I'd put money on it being their lifestyle. They may not appreciate the level of heating needed to compensate for their cooking/showers/breathing/ironing/washing etc. For context, I live without heating as much as possible at the moment because of the expense and I'm mega cautious after a nice hot bath. I keep the fan on for 15mins after whilst the window is also wide open. The bathroom window then stays open for at least an hour. I have no damp issues. You can go to the expense of fitting under floor heating but will they use it fully? If they don't because of the costs, you're back to square one. Underfloor heating isn't cheap to run.

I will be a landlord again in a few years (was already one in the past) and I'm going to look into a smart heating hub so I can keep tabs on what heating my tenants are using to make sure the temperature/humidity is looked after correctly.

Thank you. My surveyor said the same condensation is usually the occupants causing the issue. They insist the flat is well ventilated and heated. The smart heating hub is a great idea. I'm going to ask the letting agent to install one.

Just a quick update. XRays you were 💯 correct. It was just inadequate extractor fans in the kitchen and bathroom, so both will be replaced. The airbricks I installed are helping, too. The gutters are also blocked and have asked the managing agents to sort out.

Thanks, everyone, for your help. I'm relieved it's a quick fix.