YES they have already stuck down about 10 tiles. OSB is 18mm thick. B & Q website write about it stating.....
OSB is a versatile and durable building board. It’s construction is similar to that of Plywood, with opposing-orientation of wood fibres that creates rigidity and strength. OSB has superb load-bearing properties, excellent cross dimensional stability and an attractive wood patterned finish.
- Suitable for wall sheathing, flooring, roofing, general construction and rennovation work, formwork and long term site hoardings.
- Load bearing/structural board for use in humid conditions.