/ Sounds like another job for your 4'6" stone roof slates you claim to
have had...

Some of the bottom rows of stone roofed buildings around here have
some fairly sizeable "slates". Some of the bits lying around this
place, presumably from the original stone roof, are not far short of
4'6" long. When as "slates" they would have been 1'6 to 2' wide and
laid landscape. /q

Got a pic? Where are you? What sort of stone?

Jim K