Condesation probs

de humid ifier , something like that takes the condensation out of the air

Don't dry clothes in the house.

got one of them and started it up today, why just these two walls though?

gede humid ifie

Are these outside walls and is it well ventilated?

I had a similar problem a while back, I asked an estate agent friend who suggested a surveyor, mine was rising damp and I had to renew the damp course. I hope yours is less serious as it cost me a good few quid to sort out.

North facing walls tend to be colder & damper all year roundm however the problem is due to internal moisture so a de-humidifier is the best solution. Also try to avoid producing more moisture by drying clothes outside and opening kitchen windows when boiling vegatables etc.

you can solve the problem long term by growing ivy up the offensive walls ,never fails .

keep well ventilated in the meantime

grow the ivy outside and not inside btw ;)

whats the theory behind the ivy?

To prevent condensation you either remove the warm moisture laden air or the cold surface or preferably both.
You can buy thin rolls of poystyrene which keep the surface of the wall warm which often helps on those North/East facing walls.

condensation happens when the warm air carrying water inside hits the cold exterior wall, making the water condense and become solid, not airborne. The ivy I imagine, insulates the exterior wall making it less cold, sutting down the effect.

Which is clever, unless you live on the 8th floor.