Robert, The word small is not applicable here sorry to say. The ADA required gradient is one in twelve, that means legally you'd need a foot of ramp length for each inch of rise. That means (ouch) a 39 foot long ramp.
I assume this is your private home, so you don't probably have to be ADA compliant. I'd guess that anything steeper than one in eight is going to be too bloody hard to assend, and/or too steep to safely descend. You can do switch backs, you need level stops, and I've forgotten how often. The width needs to be minimum 48 inches with level stop/turns at any switchbacks also 48 inches square. Obviously a single run won't do, and it's going to need to be on legs, not just bolted to the porch frame. You gotta figger for a 250 pound person in possibly a 400 pound power chair, and if you start with such a load at the bottom of a single ramp, the leverage out at the end of the run is going to be horrendous. Those are about the starting parameters, obviously you'll have to do some serious compromising. Let's see what others suggest. What length of straight run can you get maximum? Tom Fowle
