Make it pay half the rent and utilities

Thanks to all who responded. I called Sakrete and they recommended their "Top N Bond," it's a polymer-modified concrete patch that's supposed to be good from thicknesses of 1/2" to featheredge. They say I can put it down within 24 hours of the initial pour, or after the final cure in a month. I'm going to put it down now in the hopes of a better bond.

I did-- if my measurement was off, it wasn't by much. I had this happen before when doing some under-slab plumbing repairs for a new shower, but chalked it up to not troweling it much. I guess from a liability standpoint they'd rather have people mix it too stiff and retain the strength of the concrete, than too loose, and have it be brittle and break.

Thanks-- I posted over there on your suggestion

Food is solid-- but it's really about the experience. This place is quintessential Baltimore.

I've done this before. The grout will crack because it's brittle and the shower pan and walls expand and contract at different rates depending on temp and humidity. You need something stretchy like silicone for any transition in surface, even inside corners of the same kind of surface.

I can't see those making it more than a week in the Highlandtown Walgreens before someone smashes them or steals them and takes them home to play PS5 on a cooler door. Putting those up in that store is just asking for anarchy.

I've clocked Amtrak (non-Acela) using GPS on my phone at 125 on that same stretch! I had no idea they were so fast! I didn't know this fact about MARC-- super interesting!

People are making this out to be much more complicated than it needs to be. Regular drywall (especially for such a tiny patch) is fine-- your box store likely sells 2x2 sheets of the standard stuff so you don't have to wrestle with an entire 4x8 sheet of green board on your way home. A small tub of regular, premixed drywall mud is fine too.

Regular paint and primer is fine unless you have moisture issues (e.g., no exhaust fan).

Get a small (3-4") drywall knife and a medium (6"). The 3" will be useful for your initial coat of mud (and is generally useful to have around the house for patching nail holes, etc.), and the 6" for your second and third coats. You won't need a mud tray for such a small project-- just work directly from the bucket of mud and use your 6" blade to scrape your 3" blade clean, and vice versa. Be sure to rinse them clean with water and dry them when you're done.

Buy a sanding sponge-- it's hard to oversand with them. I like the 3M seafoam green colored one (the various grits are color-coded).

Good luck!

Maybe one day I'll ride from Glenmont to Ashburn, just to see what 2 hours in one direction on the Metro is like