Then take an iron and set it to a medium heat.
How to flatten rug edges.
Ask another person to apply tape to the edge stretching and pulling the rug flat as you work.
Many times this will allow the rug to lay smooth for a while.
Smooth the rug as flat as possible along the edge or edges that curl.
When you let it dry on its own the rug should flatten out.
If they still curl upward place heavy books at each corner for another day.
This should flatten the areas out.
Get a wet sponge or a wet towel and moisten the edges of the rug once you have it unrolled and in place.
Lay a damp towel over the edges and iron them flat.
Set the corners back in their natural position.
If corners still curl upward flip the rug over and let it sit that way.
Also check to make sure that the rug you purchased is waterproof and can handle this trick.
Take a wet towel and moisten the areas where the carpet is curling.
If the ends still curl up move to the next steps.