Damp/mould gathering on internal walls

[AidanGee93]

Hi guys, looking for some help here. I love in a top flat, my rooms have some signs of mould/damp on them(see pictures, hopefully they uploaded). All the walls the mould forms on are the internal walls of the external end of the building.

 

Looking to renovate I.e paint, coving etc but I'd rather stop the mould/damp. Any ideas?? I have placed some cheap dehumidifiers around, will a plug in one at a better quality be a good idea? Also windows have the trickle vents open all the time for air flow. Will adding some heat to the house help this?

 

Cheers guys, hopefully get some tips.

[ETC]

No trickle vents for a start.

[JohnMo]

You need proper ventilation strategy, air through trickle vents, but what's driving the throughput?

 

Ideally you have cross ventilation - air comes in via dry rooms and out wet rooms. Under doors need a 5 to 10mm gap so ventilation doesn't stop with doors closed. dMEV fans in wet room would provide the motive force for air movement. Then you need to make sure the house is heated, this drives the humidity levels downwards.

[Redbeard]

Try Greenwood Unity CV2SVGIP Low Voltage dMEV Fan

 

I have 3 and rate them highly.

 

Re dehumidifiers, yes, plug-in. Do you have the little boxes filled with absorbent crystals? They are OK for keeping a cupboard fresh (if you remember to change them - note to self!!) but won't do much in a big space.

[AidanGee93]

20 hours ago, ETC said:

No trickle vents for a start.

Sorry there was one trickle vent in one of the windows but looks as if it was added...is it possible to add a trickle vent to a window?

[AidanGee93]

19 hours ago, JohnMo said:

You need proper ventilation strategy, air through trickle vents, but what's driving the throughput?

 

Ideally you have cross ventilation - air comes in via dry rooms and out wet rooms. Under doors need a 5 to 10mm gap so ventilation doesn't stop with doors closed. dMEV fans in wet room would provide the motive force for air movement. Then you need to make sure the house is heated, this drives the humidity levels downwards.

Thanks for responding, very helpful. I'd it possible to add trickle vents to current windows? Also doors are a bit tight especially at the bottom so may remove and plane for a good gap. Getting a ln oil radiator for the hall so there's some heat. The fan for the bathroom there is none although I tend to keep the window open and bathroom door closed, especially while taking a shower...is this good enough as if like to try the rest out before adding bathroom fan, just be a pain to install and the height of the building too etc.

[JohnMo]

You may want to try purge ventilation, as interim measure. You basically open all windows and interior doors fully, everyday for 3 minutes. Then close them. Most the building heat is within the building fabric, air contains very little heat energy.

[Redbeard]

1 hour ago, AidanGee93 said:

Is it possible to add trickle vents to current windows?

 

Yes, if there's enough frame left at the top. Look for 'uPVC window repairs' locally and you'll probably find someone who will do it.

[AidanGee93]

On 21/01/2025 at 16:49, JohnMo said:

You may want to try purge ventilation, as interim measure. You basically open all windows and interior doors fully, everyday for 3 minutes. Then close them. Most the building heat is within the building fabric, air contains very little heat energy.

Thanks mate, definitely going to get trickle vents sorted and I'll keep windows open aswell, will try this above method to get fresh air moving through and old out... cheers mate