Bradstone bradbond is a cementitious slurry primer that can be used on any paving product to help strengthen the bond between the paving and the sub base onto which the patio is being laid it is however particularly important to use bradbond when you are laying porcelain paving as porcelain needs the additional adhesion that this primer provides to bond successfully with the mortar bedr r bradbond is so easy to use you simply add water to the already blended mixture that comes in the tub an