Filling in 'gaps' where 'overlay panels' didn't fill?

[GlanMenai]

Hello!

 

I'm looking for some advice; we've recently installed the 'Loflo Lite Overlay panels' on top of 22mm P5 chipboard throughout the house. 

 

Here and there, we couldn't get the boards to fill exactly the full width of the rooms, as it's an old house nothing is square, and so there's some slithers here and there that we can't get the panels onto. We plan on putting an overlay and then some engineered wood directly on top of these panels, but, I would love some advice on what we could use to fill in the gaps that the panels couldn't get to, as we don't want the floorboards to be sitting on top of 'nothing'.

 

I read that we could use adhesive foam while laying the floor boards, or maybe some self levelling that would allow 20mm thickness - but, how can I get the self leveler onto the P5 chipboard? Would I have to prime the boards first if that was the best solution? 

 

Has anyone got any experience with this, and can offer any alternative advice on what we could maybe use to fill in these 'holes'?

 

Many thanks!

 

[PeterW]

Expanding foam (wet the gaps with a spray bottle first) and carefully fill the gaps then cut the excess back with a saw when it’s cured. 

[GlanMenai]

Hey @PeterW 

 

Thanks for that, do you think expanding foam will be 'strong' enough? I know the engineered wood will clip into each other (t&g) to make the mass one, but I'd just be worried that the expanding foam will be like a sponge, and compress in on itself if there's weight on it?

 

Thanks!