Just had a wall rendered and plastered. 3 weeks ago today. All has dried out the usual light pinky colour. All except one area about 2ft X 2ft in the bottom corner. Despite it being beside a radiator the area is a darker brown than the rest of the wall. Never changes size or colour. Is this damp or can a wall dry out darker in some places.

needawin, November 2011

you may have a damp problem behind your skirting boards , if not try using a de-humidifier to suck out any moisture left in the plaster

pango, January 2012

I would think that you may have a damp problem, OR something is behind that section. Plaster will dry at different rates, but will be more or less uniform, they plaster in batches, one batch might have slightly more water in than the next or previous, but the area a batch covers, is far greater than 2x2, and over a few weeks any differences due to mix will have dried out, and all be near enough the same colour, so something else is the cause, get a damp meter on it, not that expensive at diy places, or get someone to test around. Something is causing it, But. Look around outside the house, if it an external wall, Could be somethink simple, blocked drain, leaves etc. blocked down pipe, so guttering overflows when raining. all sort of reasons.

SD, November 2011