sentences:  Floors using small ( and smaller) ceramic tiles generally use only an additional layer of plywood (if that) and substitute adhesive and substrate materials making do with both a flexible joints and semi-flexible mounting compounds and so are designed to withstand the greater flexing which large tiles cannot tolerate without breaking.A ground-level floor can be an earthen floor made of soil, or be solid ground floors made of concrete slab.Ground level slab floors are uncommon in northern latitudes where freezing provides significant structural problems, except in heated interior spaces such as basements or for outdoor unheated structures such as a gazebo or shed where unitary temperatures are not creating pockets of troublesome meltwaters.