crease/fold in rug - can't get it out!

[justtry]

Bought rug a while back, came in a roll. There's a crease / fold in it so it doesn't lie completely flat. I have put the rug upside down to try and see if it would go flat but no luck, the attached underlay (for lack of better word) is quite rigid.
Anyone any suggestions to try and flatten this?

Loads of (heavy) books for a few days all over the top!

It is probably due to the way the rug was stored in the shop. We had this with a newly laid carpet and were told to hoover the dent as it's meant to help. We hoovered and hoovered and hoovered and it still wouldn't go away though.

Spray some water over the crease and then hold an iron over it with the steam function on. It worked on stubborn depressions from the sofa legs on my rug, worth a try?

I tried this before but no luck!

Same!! And didn't help at all. It's the underlay which is really stiff. Clearly it had been rolled up and put in a warehouse for ages.

I just tried this. It started off looking promising but now it's wet and needs to dry it seems to crease again, but for now not as deep. I may try this a few times depending on what this looks like when it's dry!!

I think it'll take some time for the crease to fall out. We bought a rug from the US that came folded and initially the multiple creases looked horrendous. The advice was to do a mix of what's been suggested above - we didn't try the dampening option but did hoover like mad and put tons of book piles in the relevant areas. The seller (Irugs) offered for us to return the rug or accept a partial refund which we did. It took a few weeks but eventually the books worked for us and the creases were history.

Some form of steam - Steam cleaner etc gets them out

So yes, water and steam iron did it in the end. There's still a slight crease but it has so much improved. It is barely noticeable. The underlayer has a hint of something plastic/synthetic(?) in it though as my iron got something sticky to it and it smelled a little bit, but most of it I got off. Next time (I think I'll try it one more time extra just in case it even helps more) I need to put a thin teatowel in between - or maybe I can just iron over a wet teatowel!
Anyway, I am happy! 😀