On May 1, 1:25 pm, The Natural Philosopher wrote:
Rookie_Remodeler wrote:
Hi!

Thanks for the reply.

"Upper floor" means the second floor. Removing the subfloor will not
help since the joists are sagged themselves. Therefore, I can either
fix the sag by adding strips of wood with different thicknesses or add
the self-leveler (not very keen on this one unless somebody chimes
in).

My concern about using the wood strips is that some of the wood planks
will be "floating", that is, will not be supported by the subfloor,
ergo asking what can be done in this case.

What you normally do is take the floor up and start planting and sanding
and cutting bits of timber up to fully level the joists.

Even better. gets some new (flat) joist and bolt them alongside the new
ones, with a level and a steel rule laid over their tops..or a string..

That will stiffen the floor a lot..

Thanks for the suggestion. However, like I said before, raising the
floor (eliminating the joists sag) is out of question. Folks who did
the remodeling before built walls that would have to be torn down or
the ceiling (and roof) would go up.

So, the question is. How much a 15mm thick wood plank can "float",
that is, assuming I use the different thicknesses strips to level the
floor and nail the hardwood planks to them. So, how much they can
"float" without the support of the underfloor? 20, 30, 50mm?