X2 on all that.I wouldn't rip out the tile at all, talk about easy to clean!
as already mentioned, turn the power off and pressure wash it clean. DEFINITELY add ventilation, and plenty of it! that's most likely why it smells so bad. The ammonia has to have a place to go, up and out is preferable. I would buy a through the roof chimney kit and go through the ceiling and roof. Cut holes in the tops of the walls inside and out, and cover them outside with vent plates for eaves, you can find them at your building supply store, and inside with hardware cloth.
I promise you ventilation will take care of a lot of the smell.
Also, once you start using it, keep a bag of sweet PDZ on hand and use it liberally mixed with your bedding. A poop board/tray under the roosts with a sand/pdz mix also keeps the smell down, as it dries the poo pretty quickly. Dry poo doesn't put off the odor moist poo does, so getting it dry quickly helps. I go out every 2 to 3 days with a kitty litter scoop and a small bucket and scoop it clean, no smell or flies at all
I don't have a problem with it.Oh sorry I thought the title "Need help deciding what to do with this coop" was a good thread to get advice/ swap ideas on what to do with my coop.