Protection of Bricks and Newly Laid Brickwork
Make provision for protecting bricks stacked ready for bricklaying and newly built brickwork from saturation and from frost in winter. If clay bricks become wet, efflorescence and the risk of staining by lime-leaching from the joints will be increased. If rain falls on newly laid brickwork before the mortar has set, the fine particle of cement, lime and pigments may be washed out, causing a change in mortar colour. Place boards or plastic sheeting on top of stacks of bricks and newly laid brickwork and secure them against wind. Care should also be taken to keep stacks stable and protect them in the event of wind. If laying bricks when rain is expected, protect the newly built brickwork, but maintain an airspace between the brick face and any waterproof covering to avoid risk of staining.
Mortar should never be allowed to freeze before it has set, but if it does so, the affected brickwork will probably have to be re-built.