Yesterday I treated all the rust patches in the floor frame. There was actually quite a lot and the more of the white paint I ground off, the more rust I discovered underneath it! At least it was all still pretty minor and I didn’t stress too much about getting it all off. Just did the worst of it.
Some of the rust before:
After grinding back most of the rust:
After that, I painted the whole frame with Penetrol, which soaks down into every little crevice and seals up the rusty metal. Once that was dry, I then painted the floor frame with two coats of Rust Guard primer mixed with more Penetrol, and then finished with a top coat of Rust Guard enamel.
It was a lot of work to do this, but I am so pleased with the finished result. It looks AMAZING!
I can now be confident that I won’t have to worry about rust in my subfloor for a very long time!