Dehumidifier

[Combwork]

Would a domestic Dehumidifier dry off and keep a medium size bedroom dry? Slight but continuous penetrating damp.

I've been in the attic and up on the roof so many times, I might as well take a tent up there.

It's an old house, thick walls made of sandstone. This stuff's slightly porous. Long term once the weather's dry sealing it on the outside might do the trick but short term, I need to do something. Has to be the right thing; outside my sphere of knowledge I've a well earned reputation for screwing things up.