The phrase "rougher surfaces" refers to surfaces that are not smooth or even. They have uneven textures, bumps, or irregularities that make them feel rough when touched. Full definition
Protect Your Dog's Paws Dogs are often left hiking over rough surfaces with tender paws. (petpeoplesplace.com)
These are mats with rough surfaces that file down the nails as your dog walks on them. (ricevillageanimalhospital.com)
Damage is usually caused by the old brake pads wearing completely through and tend to leave a very rough surface on the disc. (mechanics.stackexchange.com)