I am currently living in my grandmother's old house (built ~1940 or before) where I have yet to find any previous repairs done correctly. The house is a two bedroom, one bathroom mill house type construction in the south so it's built on a crawlspace. Initially, the house must have been one open room with a central stove. The southern yellow pine plank sub floor runs perpendicular to the 2x8 joists while the original hardwood floors consisting of 2-1/4" red oak planks, and a 1-1/2" and a 1-3/4" plank thrown in every 4' runs parallel to the joists. If I remember correctly, the sub floor planks are tongue and groove; however, the red oak boards are not T&G. Rooms were framed on top of the hardwood floors by connecting 1/2" plywood sheets to 2" x 4" lumber (thus creating uninsulated walls with a 3" gap between rooms).

The bathroom floor has sustained the most damage over the years from drain/pipe holes created in the sub floor that were left as is whenever the space was reconfigured and joists that were incorrectly sistered or jacked up with a 2x4 piece of wood below. The weakened bathroom floor slopes toward the shower/tub faucet and toilet in the bathroom and the sink and dishwasher in the kitchen which back up to them. The sloping floor caused the toilet to leak and I was able to repair the floor and rebalance the toilet until the person I trust to correctly repair the joists and crawlspace damage is available.

However, it seems water from the shower has also damaged the floor at the corner where the faucet and showerhead are located in spite of our efforts to prevent it. The wood trim in front of the tub was only held together by the paint covering it. Removing the damaged wood means replacing the vinyl flooring so I am pulling up all of the plywood that was sitting on mostly hardwood flooring in the bathroom. There must have been a leak in the past because there is plywood instead of red oak where the damage is. My first question is, how do I remove more of the plywood under the edge of the fiberglass tub without damaging the tub? I want to remove any residual mold or wood rot so it will not damage the new plywood.

Also, should I run the new 1/2" plywood underlayment for replacement vinyl flooring parallel or perpendicular to the joists, or does it matter since the subfloor is perpendicular and the remaining hardwood is parallel? I have temporarily addressed the sagging joists until they can be repaired correctly by placing two level 50" long 2x4 boards fastened together perpendicular underneath three joists and held in place by a pole jack.

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    Hello, and welcome to Home Improvement. It's really hard to read your question; would you put some effort into breaking it into paragraphs, and perhaps pruning some extraneous info? Thanks. Commented Jul 15, 2019 at 14:27

1 Answer 1


"how do I remove... the plywood under the edge of the fiberglass tub without damaging the tub?"

I don't see how it will be possible. You can't chisel or saw it from below due to the subfloor and you can't get to it from above. I think you need to resign yourself to the fact that the tub should come out...

"should I run the new 1/2" plywood underlayment... parallel or perpendicular to the joists... ?"

It doesn't matter because "the subfloor is perpendicular and the remaining hardwood is parallel", place it to facilitate easy fastening.

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