Brilliant, hadn't considered the ladder run in the pile, thanks 👍

Very complicated explanation - you didnt do a job of simple explanation.

Which type is the best for sound insulation?

the smoothedge thickness where i am is roughly 8 to 9mm (unless specially ordered). i normally recommended 10mm underlay with high density. I find you don't wanna go much higher than that unless the smoothedge is thicker. lower underlay when it wears after a while tends to sink and you see ridges where the smoothedge is.

Useful video. I've got a new rug thats too flexible, rucks up when you walk on it. Decided to back it to thicken it up to prevent this. Now deciding what backing material to use. Felt seems like a good idea for adding the thickness I want.

Thanks bud .. Extremely detailed 👍

Would have loved to hear some discussion about the thickness of the pads as well.