I bought a metal pergola on sale at the end of last summer and now I need to know the best way to install it "on" a brick patio. The patio top is 16 x 16 brickface blocks. Someone suggested I add construction-type cement blocks under each metal post and anchor the post to that instead of directly to the brickface which may crack. Any suggestions to help make this stable? Freestanding (not attached to house).