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Swing Arm Drapery Rods and the “Sag Factor”

July 1, 2014

Swing Arm drapery rods are a great solution to a lot of design dilemmas. They look great and they operate well and they are able to get out of the way when needed. But without advance planning problems can occur.  The most pressing concern with a swing arm treatment is the “Sag Factor”, also termed “Deflection.” The swing arm drapery rod is anchored on only one end. The unsupported end can be pulled down slightly by the weight of the treatment.

What does Deflection look like?

Rustic Swing Arm Drapery Rods Drawing with Deflection

In many cases, since both sides of the treatment will be seen, there can be a significant amount of extra weight in fabric alone. Add linings and interlinings and the treatment will weigh even more.  It is a good idea to calculate this before the hardware option is chosen.

Drapery weight factor should always be considered when specifying swing arm drapery rods. The diameter of the drapery rods, type of drapery rod and the type of bracketing hardware can dramatically affect the amount of weight the assembly can hold.

Instructions for figuring drapery weight:

Figuring the weight of the drapery in advance can be tricky because most manufacturers do not offer the weight of the fabrics on the samples. If you do not have any of the proposed fabric, the best way to get this number is to get as close as you can. If you have a similar weight fabric in your archives, weigh it instead. Start with this formula (illustrated below):

  • 36” X 54” (1 Yard) of Fabric = 1,944 Square Inches
  • 6” X 6” of Fabric = 36 Square Inches (The use of this size piece will allow you to weigh a small sample)
  • 36 Square Inches X 54 = 1,944 Square Inches
  • If a 6” X 6” piece of fabric weighs .5 ounces, multiply 54 X .5 oz. = 27 oz. per yard of fabric
  • If one panel requires 3 yards of fabric, multiply 3 X 27 oz. = 81 oz. total per weight per panel
  • 81 oz. ÷ 16 oz. (1 lb.) = 5.06 lbs. total weight for panel

Repeat this process for the lining and any other fabrics being used and then add it all together. This is the amount of weight your swing arm drapery rod will have to support. Once you have this number you can compare it against the specifications provided by your hardware supplier. In some cases, a second modified bracket can be used to support the treatment in the closed position. Also, take into account if you are going to use drapery weights.

Watch your mounting surface for your Swing Arm Drapery Rods!

Finally, the mounting surface is critical because of the stress created by the weight of the drapery. Even the action of the drapery rod can create more stress.  Swing arm drapery rods should be mounted into wood or some other solid surface. Drywall is problematic. Even with proper anchors, the angle of pressure when the arm is open coupled with the downward pressure from the unattached end of the drapery rod can create a twisting action. This can pull the entire bracket out of the wall!

As with any project, ultimate success is determined by the early planning and specification of the proper products.

Swing arms drapery rods require some care, but they are terrific in a variety of situations!


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