Hi all....

I have 5/8 strand woven bamboo I'm going to lay down in a 1000sf house built in the 70s.

It has the thick wood tongue & groove sub-floor, and the floor has a lot of high and low spots throughout.

Some of the low spots are 1/2"+.

I've read articles on leveling (or rather, making the floor flat) where they used shingles and then covered, seemingly, the entire house in 3/8 plywood.

My question if we use shingles to level, do we have to put 3/8 plywood over? or can I just use roofing felt as the whole-house underlayment and use the shingles and/or plywood where appropriate?

I was thinking I could also use a leveling compound or fix-it-all to feather and fill any areas where new plywood meets old subfloor.

Weight, cost, and raising areas of the subfloor 3/8" (near thresholds) where it doesn't need it is the main concern for not wanting to recover the whole house this way.

The flattening is going to be a weekend project... box stores only seem to have leveling compound "Oh Henry" and something by the redguard folks. Any thoughts of where I could get a good leveling compound ?