Quick Tip: How to Stop Silk Film From Ballooning

Item # X-HT-300012

We love using silk film for keeping foam dry and to help easily fit foam inside cushion covers. However, sometimes silk film can trap too much air inside your cushion and balloon up when you sit on it. Today we’re sharing a quick tip on how to solve that problem.

Foam wrapped in batting and silk film

First, let’s talk a little bit about silk film. It is a noiseless, light plastic material that acts as a water barrier between cushion foam and fabric. Silk Film is specially formulated to be silent under your cushion fabric so you won’t even know it is there.

It’s also used for shrinking foam so it can be easily inserted into the cushion cover during fabrication. Just cover and tuck the film loosely around the foam and insert a vacuum hose into a small opening in the film and place it right up against the foam. Turn the vacuum on and the foam will shrink up to 70% its normal size. Then you can place the foam into the cushion cover. When you turn off the vacuum, the foam will go back to its regular size.

To serve this purpose, the silk film blocks airflow. This only becomes a problem in a cushion if the film is wrapped around a cushion too thoroughly and the foam easily compresses. Then what happens is when you sit on the cushion, all the air is squeezed out of the foam and has nowhere to go, so it fills the silk film and causes an awkward ballooning. It’s an annoying problem but one that’s easy to fix.

Silk film being wrapped around foam.

Leave a 1-2 inch tall gap in the silk film along the full width of the cushion. You could do this along the zipper or on the underside of the cushion. This gives a space for the air to escape, but it won’t compromise your moisture barrier because it’s only a small space in an area that is less likely to get wet. That’s all there is to it!

You can find silk film here at Sailrite.