Black Mould

I agree with the above post. Improved heating avoiding letting the temp fluctuate too much in the environment.

I installed a envirovent system in my place few years back. Not had a problem since but it may not be all you need.

I just installed a piv today to improve ventilation in the house. A couple of hours to get it done.

It has a vent cover

Interesting!

If the insulation is missing, would that not be the cause, rather than ventilation or more heating? The latter would be much more difficult too where insulation is not as good as it should.

I have experience of this myself. I am in a top floor apartment. All I have between my home and the roof slab is foil backed plaster board. Property was built in 2005/6.

I have mould, on ceiling and corners of walls. I vent and heat as much as I can. Lack of insulation means heat escapes faster than it should. I have a dehumidifier but would rather the cause of problem was fixed than wasting money on the symptoms.

The reduced insulation in one section just means that's the coldest section of wall / ceiling, where water vapour is most likely to condense, causing damp leading to mould.

You could also take the covers off your vents, ensure they are free from dust etc. Do you sleep with bedroom door closed, you could try opening it, passive vents like that might not ventilate much if there's no internal airflow

Do you shower with the en-suite room open, or leave the door open after showering? If so, all moisture from the en suite is making its way into the bedroom, and your room is full of moisture. If you aren’t getting a mold problem in the bathroom I would say almost certainly there is an insulation issue in the ceiling in the bedroom.

cheap fixes

a roll of insulation and place it in the attic in that area, ensuring it’s pushed down to the eves properly

check vent in bedroom is clear

fit an extractor fan in the bathroom if there isn’t one

open windows after showers

use cillit bang mold remover. I was breaking a problem area for ages before then used this once, and it never returned

Interesting to see so much advice and quite frankly much of it is very good but there are some absolutely wrong tips.

Black mould should certainly be avoided and prevented where possible. It is usually the result of moisture laden air condensing onto surfaces that are allowed to drop below (generally speaking) 16 degrees Celsius. This is a key fact and must be considered when ventilation is being cited as a solution. If the left open window or even built in room ventilators are allowing in air that is below that temperature, then the problem will not be solved.

lindsay689 has a dehumidifier but apparently this only goes on in the morning. Too late, the water vapour in the air has already been allowed to condense onto cold (and worse still, into) surfaces and fabrics. The symptom of black mould on ceilings near external walls is usually indicative of poor installation of insulation. I have been working in lofts since 1965 when insulation of roof spaces became a building requirement and it is very rarely that I have come across well installed material. The eaves are difficult to get to to do the job right....and who is going to see it anyway? Well, it eventually becomes apparent, in the form of black mould.

lindsay689 I could go on for it is a very complex subject, but could be affordably resolvable. Ventilation certainly plays a part in the solution but it has to be used intelligently. Key points to remember. All human and animal activity produces moisture. Just breathing, let alone bathing, cooking, washing etc. You cannot live without filling the air around you with water vapour. That water vapour, desperately wants to become water so it will seek out any fabric or surface that is cold (below 17 degrees Celsius) and will condense on or within it. In your case, the loft insulation could have been badly fitted in the eaves or may even have been blown out of position by wind. Your ceiling is getting cold enough for surface condensation to occur. Day and night, that ceiling temperature has to be maintained. You cannot do that at this time of the year by leaving windows open or by using the built in room vents. Any openings to the outside including fireplaces, which are just fancy holes in the roof, designed to let out warmth should be sealed off. KEEP EXPENSIVE WARMTH IN THE BUILDING but use your dehumidifier to extract moisture from the air as it is produced. Do not waste using your dehumidifier if you have any openings to the outside, no point in trying to dry out the planet.

Windows can be used very carefully to change the air in any particular room. The average sitting room for example, only needs a window to be open for about ten minutes for the air to freshen. Any longer than that and the cold at this time of the year will come in and your surfaces will become cold enough for condensation to occur again.

Others have commented upon products used to remove the mould and to help prevent it coming back, that is chemical warfare, and it has a place in this battle. My comments are based upon an understanding of physics and of many years of practical experience. There is more, but enough for now.

Too much moisture in the outside atmosphere. Doesnt really work well

I leave all doors open to keep air moving and to help heat the place as warmer air from hall can move to other rooms

There is absolutely no insulation in the ceiling void anywhere in my property. I had my heating on for 5hrs this evening and living room temp is 17.3c. It's not even cold out.

I am pretty sure the roof void is not sealed properly and on windy days, even moderately, it's very hard to heat my home. With air cycling up there the heat I am loosing is being replaced with cold air. On a still frosty day, I have no problem hearing my home to 20c , which is warm enough.

I thing I am fight more than just no insulation. Moisture is getting in to the void from the roof as I have dead earwigs in my bathroom ip54 spot lens. They would only be there is the void was damp.

Even ln in summer time I have problems. In fact, mould growth and it's speed accelerates in summer time. I don't really have condensation problems, so I am at a loss to what is causing the mould when there is no cold temps or condensation .

I live in a top floor apartment. Above my ceiling is the concrete roof slab. I would gladly insulate it, but I have no access, I am going to get an engineer to have a look at options. I have sort of had it now with high heating bills, sadly without getting a warm home.

Sorry for deraiing your thread OP. I will ask the moderators to create a new thread for my issue

I hope you can get your own issue fixed. I can't offer much advice other that insulation being the issue if there is no damp in the attic and the rest of the home is ok. You seem to have a lot of condensation. I don't see leaving windows open for long periods will solve this.

I'd be quite surprised if the ceiling wasn't insulated in some way. Have you cut a slot in the plasterboard to see if there is insulation or just a void.

Conventional method would be pull out ceilings batten ceiling and put in some fire rated PIR board glued and screwed. Then replasterboard.

100%, just 12mm plasterboard

See photo. Lower is ceiling, top is roof slab.

What you outlined is the solution. It's a messy job, and who pays?

I am going to get an engineers report on this and submit to OMC.

A vent of some sort for sure.

Opening a window will help cool down the surfaces where the moist warm air gathers. Id open it for no more than 10 mins.

Real world scenarios around air leaks, mould and mositure differ from the stuff online.

yeah, the dew point is dependent on the RH of the air as well as temperature. If you can keep RH down either through ventilation or a dehumidifier, it reduces the surface temperature at which you will get condensation.

Something else to be aware of is that human breath contains a lot of moisture; I've noticed in my kids rooms that the walls and ceilings above the head of their beds are the areas most prone to mould. Where I can I've moved their beds away from cold external walls. I assume it's like breathing on a mirror, even if the RH in the room is low, you'll still get condensation because the humid air being breathed out doesn't get a chance to disperse before it hits the cold wall surface.

I got the HC Link

https://drimasterexpress.ie/