This is a renovation question but seems to be the best forum to ask. We are renovating a home built on a partially sloped lot. It was built on the most steeply sloped end of the lot to get the best views. It was built before there was set-back code in the area. This resulted in a semicircle drive (under a portico) that has a very steep (20+%) grade on the "exit" side that's impossible to use and dangerous when icy; even walking. The entrance side has a more normal grade; about 10-12%.

The existing drive's concrete is 40+ yrs old, cracked in several places, and due to be replaced. We're considering ripping up the steep end and instead replacing it, installing a retaining wall and a turning circle so one could drive thru the portico, do a u-turn and exit back through the portico; the way they came in. We have room for a 40-ft dia. circle; adequate for our vehicles, but would that be considered adequate if we ever want to sell?