I recently purchased a couple of patio rugs for an enclosed porch. I purchased them online from a home improvement store. I'm not sure if I can mention the manufacturer.

They are made of polypropylene. When they arrived they were rolled up and enclosed in plastic. There was no cardboard roll in the center and they appeared "flattened". (BTW, I had runners delivered for my hallway and rugs for the bedrooms and when they all arrived with a rather heavy duty carboard roll in the center of the rolled up rugs.)

When I unrolled them they both had a very noticeable waviness to them so I laid them out flat in the hopes they would flatten out. I even put some books and rather heavy speakers on the in an attempt to flatten them out. Nothing worked. After looking at some of the pictures posted by other customers of the same rug, you could see the waviness in a majority of the pictures.

When I looked more closely at the rugs it appeared they had regularly spaced creases in the material with the material more more flexible along the creases. I have since returned them by taking them to the home improvement store in person. The worker handling the return said he has seen this before.

Is this waviness something I should expect from polypropylene rugs?

Is there a way to "fix it"? ( I really don't look forward to fixing rugs that I just purchased.)

Is there a way to avoid it?

Any insights and suggestions will be appreciated.

Thanks.