If you are mounting your pergola to a wood deck or cement patio, the Pergola Bolt-Down Bracket System makes it easy! Simply measure your footprint and bolt the brackets into place. Insert 4 x 4 pressure treated wood posts (purchased separately) into the brackets and screw them in place. Slide your pergola posts over the wood posts, and screw the pergola posts into the wood. The result is a lasting installation that is safe and rigid. This mounting system was specifically designed for New England Arbors brand Pergolas.