Laying a Garden Patio | BradstoneAlways dry lay your patio first, a simple job of laying out the paving as you want the . Use a mortar mix of 3 parts soft building sand to 1 part cement and mix it.building sand paving,Sharp sand or builders sand ? - MyBuilderMay 24, 2012 . The paving flags are between 22mm-30mm thick. Should I mix sharp sand with the cement or builders sand and should I use 5 parts sand to 1.