Short answer
A dehumidifier acts on moisture in the air. It can be useful in some situations, but it does not by itself treat rising damp or active water damage.
Proper use
It can help in a room where the air is too humid or as a complement after analysis.
Sizing depends on the volume, the use, and the objective.
Limits
If the wall is still receiving water, the device may reduce humid air without removing the cause.
Marks at the base of the wall or salt deposits require specific checking.
Do the marks keep coming back despite cleaning?
That is often a sign that the cause needs analysing, not just the surface.
Advice
Before buying, it is useful to describe the symptoms and the room concerned.
MURSAIN can guide you toward a device, air treatment, or another solution depending on the case.
Frequently asked questions
Should a dehumidifier be left running all the time?
That depends on the volume, the objective, and the readings. Tailored advice helps avoid unsuitable use.
Can a dehumidifier replace treatment for rising damp?
No. It acts on the air, not on water migration inside the wall.