The phrase "porch floor" refers to the surface or the floor area of a porch, which is an outside area of a house usually covered and attached to the main entrance. Full definition
I gave our dirty porch floor a brand new look with a good pressure washing and a gallon of green paint. (emilyaclark.com)
We will never forget my mom falling through the front porch floor while moving us in, a huge bathroom leak that started while I was in labor with our first, me falling through the same bathroom floor and landing on an upper kitchen cabinet while pregnant with our second. (lehmanlane.net)
I painted my exterior porch floors with Chalk Paint ® without a top sealer back in 2013 and they still look great. (thepurplepaintedlady.com)