Since we have picked a natural stone tile for our en-suite bathroom, this gave us great pause to consider what was actually required to structurally support the massive weight of tile itself, plus anything sitting on top of the tile in the bathrooms (including a cast iron tub, filled with water and a person!). We’re thinking a lot of strength would be required underneath such an area, just as an off-the-cuff estimate…
So we took stock of the original subfloor that was left after we scraped the top layers of peel and stick tile, and what we had left was indeed in bad shape. Years of abuse and water damage from being both a kitchen and a bathroom, plus the bowing of the original joists underneath the floor meant that all of the tongue-and-groove subfloor plankboards were warped in the middle beyond repair and way out of level. Plus there are large chunks of the floor cut out where previous contractors had renovated to put in the plumbing originally, and replaced some of the plankboards with not-the-same-size pieces. (Not a great start for laying tile!).
Of course, the joists may not be so badly sagging in the middle, had some previous plumber in this house not gone ahead and cut through the most critical points of the joists that would actually carry the load across the floor:
In any case, the subfloor ultimately needed to come out in order to have any chance of creating a level (or at least closer to true) surface. So we did that:
and put all of the floor materials into the bin to get rid of bin #11! Thanks to our new bin supplier, Bin There, Dump That for the bin rental services.