Bad Wood Rot
Update 7/8/2022
Just want to say how important gutters can be, depending on the grade of your yard the rain running off the front of the guest house seeped into the crawlspace to the point I had added a sump pump a few years ago to pump it out the back, now the rear is sloped away and does not leak into the crawl.
I would have thought the front drained away out the side and perhaps it did many years ago but not since I have been here, well after adding gutters to the porch it looks like the water issue is fixed, the sump has not ran since.
The crawl space has water getting in thru the foundation, this explains why the bath floor was rotting. This is a set back as I have to address this problem before I continue.
Update:
Looking at the issue I found the ground is soaked in several areas around the guest house and a small creek that has the run-off from the field is only 7 feet away from the back of the house, water is getting into the crawl at a pretty good rate when it rains hard.
After heavy rains I can see puddles on the front steps to the guest house, the slope of the ground is the cause so short of grading the ground I chose to install a sump pump system.