Hi everyone, We have a problem with efflorescence coming through a section of our interior walls ( about 10ft x 6ft) A builder has quoted the following estimate for the job for taking off plaster fo sections of 2 walls, back to stone work. Tanking to go onto stone work first then dot & dab insulation boards, with finish plaster to stop damp & salt coming in. Parts & labour £1750. Do you think this is a fair estimate?