The product is fully constructed with treated southern yellow pine. It stands on laminated 8x8 posts with decorative post skirts to cover the anchor brackets (included). The three-piece 2 x 6 arched joists span across the side and the 2 x 4 top purlins span the length. Each intersection is notched to lock the top together to resist warping. The dual-ply header carries the roof and keeps the pergola looking its best.