Do I need another subfloor?
Building a seasonal cottage. I am insulating the floor with 1-1/2″ rigid insulation on top of a 5/8″ T&G subfloor. Finished floor will be a floating laminate snap-lock system. Would you consider floating the laminate directly over the rigid insulation, or do I need to sandwich the rigid insulation between another layer of 5/8″ subfloor?
Just my opinion, but 5/8" subfloor seems a little thin. But, I don't really know. I'm sure others will reply.
It might work, but I would want a subfloor over the foam.
The reason is that the laminate floor will flex under load and apply point pressure to the foam. Now foams are rated at 10-25 psi so it will still PROBABLY spread the load out enough not to dent the foam, but it might. Also even if it does not dent the foam the floam might flex enough that it cause localised stess on the laminate and it cracks.
For example if you have a chair leg that happened to be right on an edge of the laminate.