Hi All
Solved the problem of my 5' x 4' porch floor that dropped by an inch over the length. To big a drop for a standard levelling compound.
Found a self levelling floor compound at a local tile supplier that will easily take a 40mm difference. The manufacturers don't claim as much, but the tile shop had a display sample over 50mm thick.
Comes as a 25kg bag and a 5 litre of latex solution.
Consistency of single cream, levelled the area with minimal towelling, set as smooth as a babies bottom in a couple of hours.
Highly recommended - works on wood floors as well;