I've built a shed which sits on a frame built of 2×4's and those in turn sit on 4×4 runners, and the whole structure sits on a concrete patio.
The top of the shed floor sits approximately 8" above the patio.
I am using 12" aluminum ramp kit top and bottoms (pic below). The most weight that will be used on the ramp is a riding mower (Cub Cadet XT1 42" – approx 500 lbs) plus rider (say 300 lbs).
I plan to use 2×12 PT lumber to create the ramp and add non-skid traction strips to the lumber for traction.
I have a decent amount of clearance in front of the shed (approx 12') but the ramp still has to be short enough to allow the mower to be aligned properly for climbing the ramp, so the question is – what's the minimum length the ramp can be to ensure a safe trip up the ramp?
These are the ramp kit pieces I'll be using.
Best Answer
5° is standard (ADA) which is 1:12. So at 8" height you would have an 8' ramp. If this is too long to line up the mower, shorten/steepen it as little as is necessary for you to use it. How steep is too steep is impossible to know without understanding all the circumstances.
Find a solid sloped surface somewhere nearby and test drive the mower up and down, to get a feel for how steep is driveable and safe on your mower.