I need to install a handrail on our back porch steps. They are constructed with paver bricks and, I believe, sandstone. The sandstone slabs on the steps, as well as the brick on the steps, are cemented together. I'm afraid of drilling and using expandable fasteners, will the stone fracture?? The pavers on the top and on the patio are simply set in paver base. Any ideas? I would really appreciate any help offered!!!