Steam in roof space in summer?

[Fredde87]

Hey guys,

I have a leasehold flat on the top floor of a 5 story building in London. I have an issue in the warmer months in that somehow the roof space (the building has a flat roof so I am talking the small gap between the roof and the celotex insulation above my plasterboards) gets filled with hot damp air in the summer months.

This causes condensation which then gets through the downlights or runs through the celotex joins and then stains the ceiling.

For example yesterday it was 22C outside so it was one of the those days where the problem was more obvious. I noticed water dripping from my bedroom light fixtures. So I took one out and what I saw was very hot and damp air come out of it. Putting your hand up the hole it feels like a steam room up there.

When researching condensation issues I mostly find the opposite, of people having issues in the winter when the roof is cold and the flat/house is warm. But I have the opposite problem, I guess the roof gets really hot in the sun during the day and then it heats the roof space and then it meets colder air from inside the flat (by cold I mean like 24C or whatever it might have been inside).

I've ordered a couple of wireless temperature and humidify sensors to stick up there to try to work out the dew point.

But how is this problem supposed to be prevented in the first place? Do I need better ventilation? But if so how because I have the roof joists that of course go across so even if I add ventilation in one end it will only add ventilation between those two joists?

Or is my theory completely wrong? I dont see where else this damp / steamy air can come from since I am the top flat. Theres no leak from my boilers flu and it doesnt correspond to using the shower and the extraction fan for the bathroom works correctly.

 

[Swwils]

As a leaseholder, maintenance of the building's structure, including the roof, typically falls under the responsibility of the freeholder or managing agent. Condensation issues affecting the roof structure are therefore not your responsibility to resolve. I recommend you notify your freeholder or managing agent of the problem as soon as possible. They should arrange for a professional assessment and rectify the issue at their expense.

 

[Fredde87]

As a leaseholder, maintenance of the building's structure, including the roof, typically falls under the responsibility of the freeholder or managing agent. Condensation issues affecting the roof structure are therefore not your responsibility to resolve. I recommend you notify your freeholder or managing agent of the problem as soon as possible. They should arrange for a professional assessment and rectify the issue at their expense.

Thanks. Sure I am aware of that. The problem is I have one of these dodgy freeholders that does nothing to maintain the building, that commits fraud against the leaseholders etc by creating fake invoices or works etc. I have spent over £10,000 in lawyers over the last 7 years to fight various cases of them not fulfilling their legal duties etc. Its so bad that I have enough material to write a book about it one day.
So if I report it to them now nothing will be done about it. It took 7 years to get them to repair the really obviously leaking roof so they wont do anything to investigate a bit of steam and staining on the ceiling.

So what I want to do is understand the issue and try to pinpoint the cause first. Not so I can do works to the roof myself, but so that when I bring it to the freeholders attention I can do so with somewhat of a good understanding of the issue to minimise the amount of pushback I will get from them. Its much easier to get them to do things if I already have a proposed way to resolve the issue when I approach them as they then might see it as a cheaper/easier option to send their regular contractor around than to fight against it for the next 5 years.

 

[Swwils]

Any investigation or data you collect may not be regarded as credible or admissible by the freeholder, or indeed in any potential legal case. Only findings from a qualified professional (like a chartered surveyor or building scientist) will carry weight.

 

[Fredde87]

As a leaseholder, you are not responsible for diagnosing or fixing structural issues related to your flat's roof. Moreover, any investigation or data you collect may not be regarded as credible or admissible by the freeholder, or indeed in any potential legal case. Only findings from a qualified professional (like a chartered surveyor or building scientist) will carry weight. Therefore, if you have concerns, hire a professional to examine the issue. Their report will provide authoritative backing when approaching your freeholder.

I have hired enough surveyors in my 8 years in this flat I know very well how it works.

Than you for your advice. But this is a DIY forum and therefore I would like to broaden my understanding and learn about the issues either way.

 

[SpecialK]

Do you have a warm or cold roof? Are the downlighters sealed to the ceiling with the rubber ring to stop condensation? Sounds like a ventilation problem...

 

[JohnD]

I think the roof deck is wet. When sun shines on it and makes it hot the existing water steams out.

Whether the water originates from roof leaks, or vapour escapes through the holes in the ceiling for your ill-advised lamps, I cannot guess. Is there a hole in the bathroom ceiling?


Where does the duct from your bathroom and kitchen extractors run?

 

[Fredde87]

I think the roof deck is wet. When sun shines on it and makes it hot the existing water steams out.

Whether the water originates from roof leaks, or vapour escapes through the holes in the ceiling for your ill-advised lamps, I cannot guess. Is there a hole in the bathroom ceiling?


Where does the duct from your bathroom and kitchen extractors run?

I think you got it spot on. Its a bit hard to say because we have had poor weather all summer. But I basically bought two bluetooth temperature sensors and put one in the ceiling and one in the room below. I could see that in June the temperature was getting up to 55C in the roof space and humidify was ranging anywhere from 30% to 70%.

I looked in my bathroom and realised there are some small gaps around the lights in here. So as a test I put some duct tape to seal them. The problem slowly started getting better and hasn't come back in a while.

So I think there was water trapped there as well as maybe a bit of moisture coming up there from showering, just topping it up. And then as you say when the sun heats the space it turns into humidity and it got so hot up there that the due point would be hit around my lights where it meets the cooler room temperature and cause the moisture to turn back to water and drip down from the ceiling lights.

Thanks for all your assistance! I'll update this thread next year if the issue comes back