I think a point has been proved here, lime has to be by experienced hands, the building as a whole has to be looked at, everything outside affects inside and vice versa,it's like telling a dog to sit and go at the same time with lime outside and normal sand and cement render inside, lime won't fail ,the poor application of a product will fail, I am not a lime expert and I would seek advice if I undertook lime works, seanlar is an expert..