You could stack 3-4 against the building and then turn the rest the other way to make a ramp. Make sure to lag bolt or screw them together. You could even place another at the end of the ramp to keep them even at the bottom.
BEWARE OF THE KIDS, THEY EAT EVERYTHING I Shoot!
Give a man a fish and he will eat for a day...Teach him how to fish and he will sit on a boat and drink beer all day!