The grey faded area is actually the sticky rug pad that was used to hold the rug in place on carpet.
It is called T-bond rug under pad and it is used to hold rugs in place on wall to wall carpet.
T-bond is sticky on both sides to adhere to the carpet and to the rug. It is used to stop rugs from moving so much on carpet. It has a short life span though and stops working once it gets dirty. It loses it’s stickiness and stops holding the rug in place.
It also can take the colour out of your rug as shown here.
The T-bond could almost be used as a rug in this situation, it would be a bit sticky though. This is a great example to why you need to use the right pad for your rugs. Since the most common type of flooring is a hard flooring there are more options for area rug pad.
But what about when you have carpet? There are less options. Many may say that since you have carpet why use an area rug? Most people use a small rug in front of entrances and if you are renting using an area helps keep the carpet cleaner. Plus area rugs add colour to a room that carpet cannot do.
So what do you do for rug pad on carpet?
There are a few types, there is the sticky T-bond, and one that has small plastic nubs and non slip top, for large rugs there is a half inch pad that is soft on one side and stiff on the other. Those are the three ones I know that can be found in Victoria, BC.
Nothing will completely stop a rug from moving on carpet, the carpet fibers move with every step, but the rug pad helps your rug not stretch out of shape. Just be aware that not all rug pad is good for every rug and every floor type.
Thanks for reading, RugloverMary