Tiling a Conservatory floor some basic questions (please)

[Rich]

If the joint is 5mm wide, you might be able to get a thin grinder disk in there to cut out the joint but be very careful not to chip the edge of the tiles. I use a Fein multimaster to cut dry grout out of joints, its brilliant. I dont know if it is the type of tool you can hire? Might be worth a look.