Posted By Robert K Lewis Claire Are you sure the property has net been damp treated in the past, if so what you might have is Limelite renovating plaster which is still extensively used as it can be applied to damp walls without adverse effects. I don't recollect any ICI products of this nature as this is I think a Tarmac product and part of a range of similar materials. Look it up on the web and you can find the links. The other solution may not be the best but you could opt for a paint that will not be affected. It is better environmentally overall to do this rather than to hack off the whole plaster and replace. Further possibility is to get a sample analysed but this is perhaps OTT. Bob