Hi everyone, we recently had a carpenter redo the whole subfloor plus install laminate in one floor of our flat. The building has concrete ceiling/floor, not level at all. There are a few centimeters (this is based on what they said, I might be misremembering) of difference in floor level across different rooms. My request was for a squeaky-free flooring, so I asked them to redo the subfloor too. They laid down joists on top of the concrete, spaced 40cm. They used Broadfix packers to level the floor (checking with a laser level). They then screwed the joists into the concrete (unsure about the space between those fixings). On top, Caberfloor P5 18mm, Gorilla PU Glue between the sheets and screwed them on the joists (no glue between joists and chipboard). Underlay and 12mm laminate on top. Result: there were a number of spots where the flooring squeaked. They fixed that by adding more 10cm screws that went from chipboard to concrete. a few squeaky spots still remain some other spots feel "soft" under the foot, as if that part weren't supported enough underneath and the flooring gave in a bit when you step on it The carpenters think everything is fine and they're not willing to redo the subfloor. I am now planning on redoing the subfloor myself, with a tight timeline. Plan: Take caberfloor out using a circular saw (so I don't cut the joists underneath). This is already in progress. The sheets are glued so I could not find a way to access the joists without cutting them. Add more packers under the joists to fully support the parts where the floor is uneven. The carpenters said having packers every ~1mt would be enough but clearly that wasn't the case Use PU foam to fill all the other gaps between joists and concrete, as advised by another installer. Lay down WISA SpruceFloor 18mm Glue sheets of SpruceFloor using Egger D4 MDI glue Screw sheets to joists using flooring screws, spaced as per SpruceFloor installation guide. I am going for the Optimaxx PZ Countersunk 4x50mm screws Install underlay and laminate Does anyone have advice on my plan? Are there better glues/screws that you would recommend over what I've chosen? The SpruceFloor installation guide also mentions that gluing the sheets to the joists could also be an additional measure to reduce the change of squeaks, however on this forum I've read a number of posts against that practice. Increasing ply/chipboard thickness to 22mm and redoing the joists layout is not an option. Any feedback is appreciated!
