I'm getting confused about condensation - help!

[QueenBoudicea]

I've just found a damp patch on my bedroom wall. It's an external wall in the corner.

No tumble dryer so clothes dry on an airer on the landing to get warm air flow from downstairs. Heating is currently on for an hour in the morning and 2 in the eve. I've changed jobs so I'm out of the house for longer hours so I don't think the house is being aired enough.

The bathroom has an extractor fan so would it be better to leave it on all day and dry laundry in there?

Or should I have the heating on more?

I leave our upstairs windows open a tiny bit "on the latch" so you could lock them like that if you wished - is that an option?

Bit expensive to leave the extractor running all day!

Check there is not a leaking gutter near the damp patch too.

Ventilation is key here - but you could always invest in a dehumidifier to help ?! - check for leaky down pipes or something splashing outside in that area too ?! Keeping the vent in in the bathroom may help - if it leads off the bedroom and you keep the door open - but not if you are using a dehumidifier too though !

Have checked outside and guttering is fine - no sign of external damp. I found the patch begind a pile of books that I'd stacked up in the corner at the end of the summer.

Would a dehumidifier be more expensive to run than an extractor fan?

Not sure but dehumidfier would solve the problem better.

Are you able to leave the windows open during the day - that may well be enough?

If you found it behind a pile of books it could be that as it was a cold external wall that the books were just impeding the airflow enough to start a problem.
Start by not putting things in front of that section of wall so it gets properly circulating air.

Thanks wonky I have same problem with some piled up books by an external wall and was freaking out that the rising damp which is everywhere else was there too. Will clear space and hope for best.

Yup - have moved everything clear from the wall abd gave it a good scrub with bleach. It's not damp to touch today and no condensation build up although as I'm here I've had the windows open and washing on the line!

We had a problem damp patch on an external wall and the outside wall needed some repointing (replacing mortar between the bricks) as even small cracks can let moisture through.

Also drying clothes inside add 8 lt of water to the moisture created from bathing/cooking etc.

Heat,lots of ventilation and keeping furniture slightly away from walls to allow air circulation will all help keep mould and damp away.

I think having heating for just 3 hrs in a whole day in this weather (cold and damp) is an obvious answer! Leabing windows open all day is hardly realistic for security reasons and also all the cold air will get in. Just heat more, and open windows for longer at weekends at least (but not for long if pouring with rain).

if you have outside space, use it for drying. A day like today where I am (damp and no wind) won't work but plenty of days do. Try to arrange your washing schedule according to the forecast.

An extractor fan will run for about 50 hours on one unit (kWh) of electricity, costing you in the region of 12p to 14p

Expensive?

Run the extractor with the window and door closed to prevent the water vapour diffusing therough the house.