 He accepts the need for replastering when significant amounts of ground salts have built up in the existing plaster, but he then goes on to say that replastering is often carried out to make up for an unreliable chemical DPC.He also suggests that damp-proofers have an incentive to carry out more replastering than is strictly necessary as it allows them to finish the job without having to wait for walls to dry out, resulting in faster payment.Although the sand-cement renders typically installed as part of a rising damp treatment are very effective at holding back damp and ground salts, they have a number of disadvantages.