Craig Young
Hello Julie, if the sub base wasn't installed correctly then it all needs to be taken up and replaced correctly. I've had to do this myself on several occasions on drives and patios which were incorrectly installed by incompetent installers. It's hard to comment without seeing the job but if the sub base is to blame there will be obvious signs of settlement such as dips and bumps. The slabs could be loose because the mortar wasn't of the correct mix or was laid using the cowboy 5 spot method. You'd be best to get more quotes before going ahead. Good luck, Craig
