Downstairs toilet

FreeBear

ian1246 said:

LOU40 said:

I don't dry washing in the house. I have a dryer in the shed. Always open windows in the daytime. Already have a humidity reader, never goes below 60, even in the summer. Extraction fans don't work in my kitchen and bathroom, they make the room fill with condensation and had this problem in the kitchen and bathroom with old windows too. 

If it never goes below 60, your problem is high humidity then. You need a dehumidifier and you need working extraction fans.

Over the last few days, humidity in my house has been between 60% and 70% depending on room. Temperatures have been fairly stable at 18-20°C. Minimal ventilation, and no condensation.

@LOU40 What would be of interest is the upper limits of your humidity levels, and the temperatures (the two go hand in hand).

ian1246

FreeBear said:

ian1246 said:

LOU40 said:

I don't dry washing in the house. I have a dryer in the shed. Always open windows in the daytime. Already have a humidity reader, never goes below 60, even in the summer. Extraction fans don't work in my kitchen and bathroom, they make the room fill with condensation and had this problem in the kitchen and bathroom with old windows too. 

If it never goes below 60, your problem is high humidity then. You need a dehumidifier and you need working extraction fans.

Over the last few days, humidity in my house has been between 60% and 70% depending on room. Temperatures have been fairly stable at 18-20°C. Minimal ventilation, and no condensation.

@LOU40 What would be of interest is the upper limits of your humidity levels, and the temperatures (the two go hand in hand).

Your house is warm enough the internal walls are likely at a temperature above the dew-point, preventing condensation.

Lou40's however stated where this problem is occurring is in her UNHEATED downstairs toilet - if its unheated, I would imagine her internal walls in that room are sufficiently cold that any humidity in the air settles on the walls and condenses into droplets - causing the wet.

High Humidity means there is sufficient moisture in the air to cause significant condensation on cold points. Reduce the moisture (or insulate/heat & remove the dew point) and you get minimal condensation. 

Absent of working extractor fans, it's no wonder humidity levels will be so high throughout the house & condensing in the coldest room...

ThisIsWeird

Ian has, I think, struck on the irony of improved windows - they can reduce the ventilation and cause bigger damp issues. Do they have trickle vents on them? Are they open?

Lou, what do you mean by "Extraction fans don't work in my kitchen and bathroom, they make the room fill with condensation and had this problem in the kitchen and bathroom with old windows too."? Are they not working at all, or just seem ineffective? Either way, I suggest they need sorting as a priority.

Although your house feeling (or actually being) cold often doesn't help condensation issues, it isn't the enemy it may first appear. You could turn off the heating in, say, a bedroom, hang your wet clothes in there, and you wouldn't have any condensation forming - provided you fully open the windows in there. Yes, it'll be bludy freezing in that room, but it'll be dry. So, 'cold' isn't the main issue, but ventilation almost certainly is.

You need to tackle the main sources of moisture generation - the kitchen and bathrooms. These must be extracted away at the point of generation.

That downstairs loo must have an extractor in it too? Don't be afraid to leave it running for an hour - they cost pennies to run.