dry patches on internal walls..

[ray316]

l have a few dry patches on a internal wall that has wallpaper on it.. the wall is in the dining rooms chimney wall, it's not damp or wet .
l have pulled back some of the paper where the patches are near the skirting boards and the walls are dry but powdery, the walls are concrete/stone with plaster finish..
l've seen on here before someone mention a name for powdery/chalky walls could this be the problem with this wall and if so how can l cure it..

 

[misterhelpful]

You are probably referring to efflorescence, which is basically the salts within the wall crystallizing usually due to some moisture escaping.

Providing the wall is dry, you can often solve the problem by dry brushing away the salts and applying an alkali resisting primer before redecorating. Do not apply any form of moisture to the wall (even fillers) before applying the primer, which should be applied directly to the plaster/render and not to any existing decorative coatings. If this doesn't solve the problem you may have to look into specialist products for the job.