Planning to overboard the existing floor with ply prior to laying a new engineered wooden floor.
Problem is that part of the floor is old concrete/cement where a range used to be. It's breaking up slightly on the surface and seems quite, errm, crumbly underneath.
I thought about using wall type fixings to try and anchor the overboard down as I don't want it to 'rattle on the concrete area.
Equally, I don't want to end up with the whole lot coming loose after a fortnight.
So, dig out the top few inches and lay a screed over it or just go with the wall fixings/anchors approach?