Bag rubbing is a technique where a bag (normally made of hessian material) is used to rub the lime render to give it a roughened finish and does not cover the ‘character’ of the wall.
The joints of the masonry are prepared the same as for pointing, cleaned out to an average depth of 25mm to form a key. This depth will vary according to the nature of the stonework, but should not be less than 20 mm.
The joints are then thoroughly cleaned and washed out by use of a hose (fine spray nozzle only) or suitable pump up sprayer. A single coat (following any preparation required for deeper pockets) of lime mortar is then applied fully into the joints.
After this the joints are ‘rubbed up’ normally using hessian sacking or some other type of suitable material in order to press it home. Then after the initial ‘set’ has taken place it is rubbed over again.