I have a 12 ft covered overhang along my barn that spans 48 foot. The base when we built the barn last year was a lot of gravel and then a lot of packed lime. Thought this would be perfect but it is far from it 
The auto waterer and the hay for the horses is under here, so they spend a lot of time under this overhang. Now with any rain, and with the horses urine, it is a deep mucky nasty mess that doesnāt really ever dry out. One of my horses has a previous tendon injury that is healed BUT I do not want her to be walking in that deep mucky stuff. I know I need to do some grading to try and keep some of the rain water from running under the overhang, but not sure I can totally fix that either. So, I need ideas on what to do to fix this. One idea I had was to concrete this area with a rough texture or grooves in it so it wouldnāt be slick (horses are shod half the year). My concern with doing that however is I donāt want it to be a ice rink in the winter and have the horses slip and fall and get injured that way. So I am looking for options on what to use under this area and what your thoughts are on using concrete. Thank you in advance!
No concrete! Too slick, too hard to stand on for hours on end. How many horses are using this area?
It sounds to me like you have a grading issue hereāas in, your water flow is back under the barn instead of away from it. After you address the grading issue, you need to build up the footing under the overhang, creating a ātableā if you will, with retaining material (RR ties, landscape timbers, etc) to hold your footing in (I use packed gravel). I would also recommend adding rubber mats to the area where the water is and where you feed hay. Are you cleaning the overhang daily? It is essentially a stall, so needs to be cleaned as such.
I have a 12 x 36 overhang on my barn too, with the attached sacrifice area graded to slope away from it, with footing built up and held in by RR ties. I live in the very wet (well, not recently! dealing with DUST now) Portland OR area and my overhang is never this way.
Is the overhang footing packed hard? If it is too loose, I can see it becoming a deep, mucky mess. Maybe pull it all out and start fresh? What is the area beyond the overhang footed with?
I know how frustrating this issue can beāgood luck, I hope you can resolve it.
I dealt with awful mud and muck for 8 years, then last fall I finally bit the bullet and had the HoofGrid system put in the runs that go from my stalls, under the 12 foot overhang and out to the end of their 40x24 foot runs. It changed my life. No mud. Nada. No standing water. Itās heaven. I picked the runs every day anyway, so keeping the manure up isnāt a change for me. I also had it put down in front of the gates and by the water trough.
Why did I wait so long??? All that misery could have been avoided. Itās not cheap, but as I said, it is worth it.
What calvincrowe said, with the additional thought that, depending on your situation, a french drain can work wonders to keep all moisture moving continuously away.
