Wood – Techniques for leveling small section of subfloor

flooringframinghardwood-floor

I recently had my back door removed and replaced with a sliding patio door. When framing the new opening, some of the framing was rotten and replaced. Due to the house being 118 years old, things aren't always perfectly square and level. The new subfloor is a bit sloping right around the door. The framers installing the door said this would be no big deal for the flooring guys, and that they are used to this sort of thing.

Turns out, 2 flooring guys say they can't deal with this. The slope is about 1" over 12", then the 3/4 plywood the door is on.

What kind of options could I employ to level this area out? While I could fabricate a bunch of large shims to exactly match the profile, it would be a time-consuming hassle. Would something like a self-leveling concrete or epoxy resin type material work in a situation such as this, if the area was adequately sealed from leaking? What other options might there be?

Here's an image of the overall situation. The subfloor on the right is the 'original', while the vertically oriented plywood is the new subfloor installed by the framers for the door.

Overall Situation

View of the overall deflection. The old subfloor is reasonably level, and this picture was taken with someone stepping on the level placed in the gap in the flooring. The difference between the ideal and the bottom is about 1".

Deflection overview

Another view
Detail

Best Answer

This looks like a job for self leveling compound. I would probably do it in 2 pours it looks a bit thick for a single pour. What kind of flooring are you installing? It looks like there will be enough height at the door for just about any kind of flooring Once leveled.

Folks that haven’t worked on old homes don’t realize true dimensional lumber was once used. Plywood is thinner the 2x4” are thinner today and may be the cause of the height issue.