What do do when you come across a half wood half concrete room ply over a couple of inches drill and plug or leave ply short of wood and screed up to it wht is the reccomended way as no one I ask ever seems to no!
I have been just getting a good fix where they meet by using gripfill then screed over the joint with a wood screed.
as Daz and Merit says, take ply just onto concrete and glue. I then feather the edge with rapid and skim over the lot with fibre screed.
definately the best way to do it, although most customers seem to want the cheapest option these days not the correct solution. Had one today rising damp, dpm has failed but they wouldn't accept they needed to re concrete or asphalt it as one of the larger stores told them they could float solid wood over concrete ontop of an underlay with a "dpm", I tried to tell them it wasn't a proper dpm as the moisture will force through in the end I just walked away from it and told them i'd see them in 6 months.
