I was talking to a lady the other day who was saying she has had a damp course put into the brick walls of her house. Apparently the builder took out a few bricks at a time, put in the damp course then put the bricks back and took some more out. In this way he did 2 complete walls of the house in a day. Quite frankly, I found this hard to believe. I can't see how the new mortar would have the strength to support the weight of the house. If this technique is OK I might think about getting my house done, as I think the damp course in my walls was just painted on and there is rising damp in places.