Adding stateliness to the graceful curves of this pergola are the impressive supporting columns. Ideal around the home or in any commercial space. This pergola structure is supported by eight 10" columns. The 2 pergola carrying beams are 3 1/2" x 7 1/4". The number of 1 1/2" x 7 1/4" arched cross members you require will depend on the length of the pergola you choose. The cross members are notched for easy assembly. Twelve laths, 1 1/2" square. The height under the structure is 8' 1 1/2". Cellular Vinyl.