I'm not sure what kind of tree that is. With some trees, having the roots that way is normal and healthy. Some trees suffer if their surface roots are buried so research that before laying on a lot of soil. The water coming off of the pavement has a lot of velocity. Porous pavement is very green but expensive. Conceptually, look up things like french drains and water bars. You can also surf Erosion Control magazine for free on the web. Also check websites for Ohio's department of transportation and department of environmental protection (or whatever the equivalent departments are in Ohio). Here is a link that might be useful: Erosion Control magazine

Thank you both, Omelet and Joseph Corlett: I am just starting my research, and so of course I started with Garden Web! I should add Garden Web slash houzz! But next thing is I'm downloading the NC State guide, Omelet, for a little light reading later this evening. Thank you for that. I realized when I prematurely broke my hip ( I was 58 at the time, long before the more usual age of 80something, and no doubt a result of the daily prednisone I take). Negotiating the shower is still a vivid memory, made worse by the memory of my mother going down as I was holding her and we tried to step over the "barrier." (I'm caregiver, she's 88 and has got dementia, and almost no speech, and lives with my husband and me). In the past five years that was the closest she came to eliciting what would have been a real "comment" from my sweet Irish mother. This house has three bathrooms: one bathroom has shower only, one tub only, and the master has both shower and tub. But both showers have a barrier! .We've had little choice but to switch her to daily bed baths. The manager of the local Council on Aging told me in passing that she pays a local company $4-5K to retrofit a bathroom so certain of her clients can stay living in their homes. (Of course it may be that part of the true cost is picked up by the construction company because they are definitely doing the best kind of charity work). I've got to say I like a $4-5K number much better than the $10-12 @Sophie Wheeler hit me with! Except I got Sophie's exact number, $10-12, in a recent conversation with a big box store employee. And Sophie I was way impressed by your expertise, the effect I'm sure of hitting me with: "dropping the joists" (requires structural work.) I know more about dropping plates and glasses... @Joseph Corlett: I agree about the positives of a barrier-free home, and many of these "universal" changes can be done now in ways that don't necessarily shout "two old folks reside here" or "careful, a handicapped person baths here" and they do look great. And costs (like for the walk-in tub) are coming down for sure. I considered a walk-in tub even (both my mother and I would enjoy it) and were we staying in this house in this area I probably would go ahead and do it. Doing an upgrade of the master bath is yes because it needs work but yet to what extent and cost is TBD as ready funds are extremely limited. The main goal of whatever work we can do is to help us get the house sold quickly and to finally return home to my husband's native California, something we've been attempting for the past decade! But I should really keep that depressing fact in mind because who is to say something else won't happen (like so many times before) to keep us stuck in this house. (Though it is a beautiful house and it does sit on an unusual acre and a half in which our sweet dog Remy does sometimes run and enjoy himself in reckless abandon; if not way back in 1999 we wouldn't have bought it for our then two precious dogs to frolic in and enjoy, having relocated Prince and Honey from their paradise in southern California to a totally new way of life in N.E. Florida. But Joseph, just as I probably wouldn't have listened to well-meaning advice, (I did marry my first husband even though my mother did try to emphasize to the very day of the ceremony that there was no need to "rush" into anything) there's no telling the young and superbly healthy that a bigger doorway to the loo is a good idea. They will need to learn this for themselves. Until then they will continue their merry way, and maybe even install what I consider to be a "trendy addition", a "freestyle" bathtub, in their first home... just place it facing out to the view, in the middle of the floor, and please don't anyone forget the "telephone," folks. A special note to @catbuilder: If your intention was to rob me of the three hours sleep I was hoping to get, you were successful. In fact I'm still wondering why there'd be a need to "drop joists" or "lower the shower floor." But I aim to learn all of these details. But you see last summer I helped a friend design a new master bath in his previous home, which he was converting to a rental. A major part of this new bathroom was a new and huge shower, installed right where the previous shower had existed. I helped him figure out the correct Schluter system, etc. and then turned my attention elsewhere. I later showed up to view the progress, and as expected the travertine tile was in, and it had been beautifully installed from side to side, from end to end; need I say no barrier, no curb was anywhere near the property!! This was a ground floor bath, as is mine. I never heard mention of the word "joists" and I think my friend would have been on the phone immediately if he did. Maybe joists and all of this work that involves did come up and he sorted it out without me. It's possible but not likely. Does the home's age matter? (When work is being done on one of his two sweet little beach homes I'm usually the "unannounced" general contractor. I'm also the unpaid GC but he knows he only gets what he does (not) pay for!) And I have to get to work everyone. You have kickstarted my brain on this project! You are all wonderful courageous people to stick your necks out voluntarily, putting to good use your expertise and doing it such a neighborly way, whether helping many of us in a huge and detailed way, or helping us figure out for ourselves just where to start. I thank you very much for that.

I think that those may be iron deposits causing your darker staining. The darkening effect is probably being caused by water saturation, as Carrera is very porous, even with sealer. All white marbles will eventually oxidize (read yellow or darker) over their lifetime - that just comes with any marble surfaces. This will most likely be a constant battle, so you may want to consider a different shower floor option. My best advice is to look for a reputable stone installer to consult with you about this, (not a tile installer). Good luck!

Post a to scale floor plan and show where the door and window are on that plan also IMOif you want to do this right you rip it all out and start over not cover up the mess that is there now, not to mention who knows what is behind those walls.IMO bathrooms are always best gutted and redone especially when you mnetion the old owners did some poor work elsewhere.As for the window get the plan done then figure what to do about the window IMO a bathroom does not require a window if you put in proper venting and maybe that is the answer to this issue I am not sure what panels you are thinking about but no matter what you do you need to rip out what is there and IMO if no tile is what you want maybe look at a acrylic tub and shower enclosure that is new and will fit and make the window smaller like it was originally . This of course will require work on the exterior . Post the floor plan please .