How long does it take for wall to dry out?

[ScarletPimpernel]

Following the very wet winter, we had water damage on the exterior west wall of the house. Water-soaked wall inside!
Problem has been found in the chimney stack. Very high up. Thankfully my builder has rebuilt the stack from the ground up. Initial problem solved.

My question is how long will it take for the wet wall to dry out completely, so that I can redecorate?
Do I need to wait the whole summer?

Have used moisture meter to take the reading >50/60% - and above.
The sunshine only comes around to the house side after 3PM. Even then, it's behind the chimney stack – so cannot penetrate both walls...

 

[JohnD]

round about a year. Exposing the wet wall, by removing furniture, wallpaper and, if very wet, plaster, will speed it up.

Ventilation does more good than heat. Put ordinary domestic fans to blow air across the surface of the walls (this will accelerate evaporation) and ventilate the rooms well by opening the doors and windows so the damp air can escape. If the house is unoccupied, open the loft hatch. Water vapour is lighter than air so will rise up and escape.

The chimney must be open top and bottom so airflow can rise through it.

When the wall is tolerably dry, you can redecorate it using a non-vinyl paint such as Dulex Trade Supermatt. It is porous and vapour can escape through it. Other similar brands will be marked "paint for new plaster".

It is not very durable but you can redecorate over it with a vinyl paint once the wall is thoroughly dry. Do not hang wallpaper for at least a year.

 

[dontbelieveawordofit]

get a dehumidifier

 

[^woody^]

Moisture meters used on the surface of masonry are not accurate.

Walls will tend to dry out outwards, and yours is unlikely to be saturated completely. So give it a few weeks after the repair and then you can replaster with a renovating plaster and redecorate once that is dry.