I am wanting to put an enginered wood floor in my 95 year old house. The house is sound, but the floor is far from flat. Can I use a self leveling compound? Are there any products that I can staple through? Or would I be better off floating the floor? Thanks.

I want to mention that no subfloor is perfectly flat and over our years in business we have seen some really rolling subfloors. When we inform the customer of the time and costs that it would take to correctly adjust and correct the high and low spots they usually decline and will live with whatever visual problem there will be. Most of the time this slight visual appearance will not be noticed once the flooring is installed.

Normally subfloors should be flat to within 1/4 inch in say 8 feet.

With wood subfloors you should try and shim up any lower spots from (below) under the subfloor by shimming up and supporting the wood decking on the floor joists. You can use a cement type leveling compound (on plywood) but it may brake apart when nailing the flooring down over it and cause crackling sounds later when walked on.

Leveling compound is better used on cement slabs that are not flat where a floating floor will be used over it.