I am putting in a hot tub outside and the guy who built my house gave me some advice.
He advised me of putting down about 3-4 inches of pea gravel and then 4 inchs of blue board that over laps to cover the 8x8 square.
He said that would be perfect as a foundation because it spreads the weight.
I like the sound of it because I am doing it myself and on a budget.
But then again it sounds strange.
Any advice?

From your profile: Alaska......

"..But then again it sounds strange?......"

Check with the manufacturer......Incorrect installation will void their Warranty......get their take on the subject.....doug