Round Tapered Columns

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Royal Corinthian manufactures round tapered porch columns from 3 composite materials that will last for generations. We offer these columns in RoyalCast™ Composite Fiberglass, RoyalStone™ Synthetic Stone, and RoyaLite™ FRP Fiberglass. All of the sizes below are available in all three materials. We offer round tapered columns from diameters as small as 6” to as wide as 42”. Some of our porch columns reach up to 30 feet in height. The majority of our round tapered columns come with a capital support ring (E) that supports the weight of a Tuscan cap. In instances where other capitals are used, the support ring is removed. Stock columns, 6” to 12”, do not have a cap support ring. If you are using these columns as column covers, please note that the “Columns to Surround Structural Supports” chart corresponds to our RoyalCast™ columns only. In general, RoyalStone™ columns will have a smaller inside diameter due to a thicker wall and RoyaLite column covers will have a larger inside diameter due to a thinner wall. Please request a specific shop drawing based on your material of choice or call or email if you need an exact inside diameter for any of our columns. Similarly, the load bearing specifications chart is for RoyalStone and RoyalCast columns; RoyaLite columns, if factory assembled, will bear significantly less weight which is why they are most suitable as column covers.

Column Diameter Bottom  Shaft Dia  Top  Shaft Dia  Bead   Width  Cut At  Bead Loss  First  Ring Minimum Wall ThicknessAvailable Lengths (feet)
(A)(B)(C)(D)(E)
6”5-1/2”4-3/4”3/4”4-1/4”-3/8”8, 9
8”7-1/2”6-3/8”3/4”4-5/16”-3/8”8, 9, 10
10”9-1/2”8-1/4”3/4”5”-3/8”8, 9, 10, 12
12”11-1/2”9-11/16”3/4”6-1/4”-3/8”8, 9, 10, 12, 14, 16, 18
14"13-1/2”11-1/2”1”7-1/2"4-1/4"1/2"8, 9, 10, 12       (more below)
14”13-7/8”11-7/8”1-3/16”6-3/4”4-1/8"1/2”14, 16, 18, 20, 22
16"15-5/8"13-1/2"1-1/4"8"4-3/4"1/2"8, 9, 10, 12, 14 (more below)
16”15-7/8”13-1/4”2-1/8”7-1/2”4-3/4"1/2”16, 18, 20
18”17-11/16”14-7/8”1-7/8”8-7/8”5-1/8"1/2”8, 9, 10, 12, 14, 16, 18, 20, 22
20”19-3/4”17”1-7/8”9-7/16”5-5/8"1/2”8, 9, 10, 12, 14, 16, 18, 20, 22
22”21-7/8”18-1/4”2-1/16”11-3/16”6-1/2"5/8”8, 9, 10, 12, 14, 16, 18, 20, 21
24”23-1/2”19-3/4”2”12-3/8”7-1/2"5/8”8, 9, 10, 12, 14, 16, 18, 20, 22, 24
28”27-5/8”23”2-1/8”12-3/4”8-1/16"5/8”8, 9, 10, 12, 14, 16, 18, 20, 22, 24, 26
30”30-1/8”25-1/4”1-1/2”13-3/48-3/4"3/4”8, 9, 10, 12, 14, 16, 18, 20, 22, 24, 26
36”36-1/2”31”2-1/8”19-3/8”10-3/4"1”8, 9, 10, 12, 14, 16, 18, 20, 22, 24, 26, 28, 30
42”42”36-5/8”3”22-1/4”1-1/4”8, 9, 10, 12, 14, 16, 18, 20, 22, 24, 26, 28, 30
Tapered Column Line Drawing

*Columns 6” to 12” do not have a ring (E) above the astragal to hold a Tuscan capital.

Columns to Surround Structural Supports

Column DiameterInside Top Shaft Diameter(S)Largest Round SupportLargest Square Support
6”4”3-1/2”2-3/8”
8”5-5/8”5-1/8"3-1/2”
10”7-1/2”7”4-7/8”
12”8-15/16”8-7/16”5-7/8”
14”10-1/2”10”7”
16”12-1/4”11-3/4”8-1/4”
18”13-7/8”13-3/8”9-3/8”
20”16”15-1/2”10-7/8”
22”17-3/8”16-7/8”11-7/8”
24”18-1/2”18”12-5/8”
28”21-3/4”21-1/4"15”
30”24”23-1/2"16-1/2”
36”29”28-1/2"20-1/8”
42”34-1/8”33-5/8”23-3/4”
Tapered Column Inside Diameter

Please note that this chart is for Round Tapered RoyalCast Columns; RoyalStone Columns tend to be slightly thicker and RoyaLite slightly thinner. The chart is fairly conservative and in most cases we can surround larger structural members than indicated. Columns that surround structural supports are typically split for reassembly so this chart allows for loss due to saw kerf. Columns that are split are no longer considered load-bearing. The inside diameter of decorative capitals is much smaller than the column shaft so the chart above will not work for decorative capital applications. To insure that the column ordered will surround the intended structural support, the column needs to be split by Royal Corinthian and the shape and size of the structural support needs to be indicated on the purchase order. Royal Corinthian will not accept any liability if columns are purchased not split and do not wrap the published structural support sizes. When a column is ordered full round (not split), it is implied that the column will not be used to surround a structural support. If the contractor intends to drop a full round (not split) column around the structural support, the shape and size of the structural support needs to noted on the purchase order at the time of order.  RoyaLite column covers are already intended to be used around structural members and are supplied as halves with integrated lap joints: They can be factory assembled but will bear a fraction of the weight of the other columns.

RoyalCast & RoyalStone Load Bearing Specifications

Column DiameterLoad (max lbs.)
6”8,000
8”10,000
10”14,000
12”18,000
14”’20,000
16”20,000
18”20,000
20”20,000
22”20,000
24”20,000
28”20,000
30”20,000
36”20,000
42”20,000

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