I have had 100 sq mt of porcelain paving installed. They used polymeric sand between the joints. It washed out straight away just with rain, sprinklers etc. They left extra bags so we installed some on a section with the same result. Even a squirt of the hose on paving removes it. I now notice a couple of pavers have moved and weeds are starting to grow. What can I do? Should I try to grout even though there is next to no gap between pavers. I have spent hours trying to research a cure. The pavers are laid on a thick bed of cracker dust.
