ngdawg

You got the landlord's permission, but you didn't discuss the most important part-compensation and ownership. You're out the money as a result.
The landlord knew this and knew he wouldn't have to shell out anything for the improvement.
When we rented our first apartment, a 3rd floor walkup over a bar, we spoke with the landlord about painting and fixing it up and discussed the cost. We presented him with the receipts and he paid us back.
Never ever sink your own money into a rental's fixing up without complete discussion and agreement on who pays for what. When we got our second apartment, in a complex, we replaced the little refridgerator with one more to our liking and painted every room and wallpapered the kitchen and carpeted the bedroom. When we moved out, we took down the wallpaper and still have the fridge, telling the management that they would have to bring back the original after we left. We took the carpet too.
Because they had not painted over the previous tenants' horrid color choices, we were not liable for our color changes. We got back every cent of our security plus the interest. Communication upfront about who is responsible for what is paramount.
Almost forgot to mention, we also planted a garden of roses, flowers and vegetables with a rock border-had to leave all that behind.
Chalk this up to experience.