Dry rot...?

[kittenwhiskers]

Anyone know how to fix dry rot? Apparently water has been leaking behind my tub surround into the walls.  Thank you!

[guitar_stitch]

Dry rot is not caused by water, hence the name "Dry Rot".

If the damage is limited to discoloration, prime and paint.  If there's actual stuff crumbling, get ready to replace drywall and possibly framing.

[Zaga]

Don't be too afraid of rot in your walls.  It seems big and scary, but with a small saw, a pry bar, and some basic tools you can pull out and scab in new studs in the wall.  Then it's a matter of putting up new drywall/cement board and properly waterproofing your tub surround.

I'd look through some you-tube videos if you're unsure of any of those steps.  Really, it can be done by a reasonable handy homeowner.

[Sibley]

And fix the source of the water, because otherwise you'll have bigger problems later :)

[Gone Fishing]

Dry rot is not caused by water, hence the name "Dry Rot".

Technically, there no such thing as "Dry Rot", all wood rot requires at least some moisture.  I think people usually use the term in association with materials that have gotten wet and partially rotted at some point, but have since dried out, stalling the rotting process.

For the OP, there are also some commercial "mold blockers" that you can spray on after the repairs that may help with any missed areas or if another leak develops in the future.