Sick of Mould behind radiator

[Mr Sparkle]

We keep getting thick, black moukd behind rads (cold spot) .

Wall have been treated and cleaned with mould killer and fungacidal wash. Dried, then painted with a mould resisting primer.

If i use matt finishing paint, the mould will come back again.

What paint finish (e.g. Eggshell, silk, gloss etc) would be best and why?

 

[endecotp]

Reduce humidity.

How do you dry washing?

Extractor fans in kitchen and bathroom.

 

[Mr Sparkle]

Reduce humidity.

How do you dry washing?

Extractor fans in kitchen and bathroom.

Forgot to mention that the problem is in the bedroom.

Washing is mainly dried outside. Main culprit is family not opening bedroon windows to all fresh air to circulate in the rooms.

Besides reducing humidity, would another paint finish solve my issue? It is only the back of rads that are having mould issues.

 

[CountryFan]

Besides reducing humidity, would another paint finish solve my issue? It is only the back of rads that are having mould issues.

I doubt it. Although it would help, I have used a mould paint in my en-suite and the mould still returns just not as quick.

 

[Murdochcat]

Leave the window open slightly over night

 

[mrrusty]

You can't change physics. The radiator creates airflow through convection. Obviously the air drawn over the back of the radiator is humid enough, and the wall is cold enough for the wall to be below the dew point so you're getting liquid condensation and mould.

You can only increase the wall temp through insulation (prob impractical), reduce the air temp in the bedroom (which will help reduce the ability of the room air to take up water vapour) or reduce the humidity of the air through ventilation and/or dehumidifier.

 

[Mottie]

What about fitting insulating foil behind the rad?

 

[Koolpc]

What about fitting insulating foil behind the rad?

View attachment 411543

This...

 

[Wayners]

20lt dehumidifier.
Run for 4 hours every evening during winter and maybe a bit in summer. If you remove the moisture in the air it can't settle behind the radiator.
We run two. One upstairs and one down

 

[endecotp]

Is this radiator a actually on?

 

[Mr Sparkle]

What about fitting insulating foil behind the rad?

Thanks. Will give this a go. Can't do the same thing, over and over again and expect different results.

Is this radiator a actually on?

No, I've whipped off the rad.

 

[endecotp]

So the radiator is a red herring then; it’s just a patch of cold wall.

What is the construction of the wall?

 

[Harry Bloomfield]

What about fitting insulating foil behind the rad?

I suspect, that might make the problem worse, in that the air flow behind the foil would be reduced, and less warmth getting to the wall.

Washing is mainly dried outside.

Mainly, is not enough - you should never permit washing to be dried indoors, even in a different room to where the mould issue is appearing. Moist air, quickly percolates around a home, and will condense out on any cold surfaces.

You suggested this is in a bedroom. What sort of construction is the wall behind the radiator? Solid double brick/double brick with cavity/plasterboard with tiles on the outside, and no insulation - beloved of the chalet bungalow design?

 

[JohnD]

You can only increase the wall temp through insulation

Or by turning the radiator on.

 

[mrrusty]

Or by turning the radiator on.

Definitely!