well guys tried this perma layer used it in 4m2 bathroom...worked a treat cleared room w.c skirting..t&g boards prep. an used sbr cut it 2 size real easy with stanley is 12mm thick mixed s.p.flex (bal) put perma layer down on this patted down with float left 2 set for few hrs then again s.p. flex an laid tiles then s.p flex grout...
only draw back i think is the working time with ply ur working when its down with this wasnt sure so left it 2 set for 3 hrs so more time on job i think...
other thing wont want 2 b lifting floor with this....could cause some real damage