I have a tongue-and-groove laminate floor, laid on 3mm foam underlay on concrete slab. After around 10 years of use, the long edge of one floorboard now drops around 1mm when stepped on. I think there was a slight step or ridge in the concrete slab here, the floorboard was supported by being locked to its neighbour, but now the tongue has snapped off. (Photo below shows pushing down hard on the broken edge.)
The floorboard is right in the middle of a large open plan space and lifting the surrounding floor is not really an option. There is also no clearance between the board and its neighbour to insert any tool.
My plan so far is:
- drill some small holes (say 2mm) through the board close to the sunken edge;
- insert screws in some of the holes, and turn until the board is lifted level with its neighbour;
- inject some kind of liquid resin through the other holes using a syringe, and plug the holes with more screws;
- once resin has set, remove screws and fill the holes with matching filler.
Does this sound like it would work?
What could I use as the liquid? It needs to be very thin, but probably not water-based. I have no experience with resins and no idea what to use.
Thanks in advance.
Best Answer
I had something similar done on two different floors (solid wood herringbone parquet and more recently on an engineered wood floor). I assume the same trick will work for laminate flooring (given that it's pretty similar to my engineered wood example).
The trick was to use low expansion polyurethane foam to fill in the voids underneath the flooring. The foam comes in a can ending with a ~2 mm diameter pipe, so all you need is to drill suitably sized holes into the floor, stick the pipe in and carefully inject foam until everything is level again. Of course you can't do this with ordinary PU foam as that expands a whole lot and would rip your floor out.