Octavian1

Thanks all for your advice and suggestions, much appreciated. I’m struggling to find online a 2nd hand replacement for the underlay, which would have been my preference. There is a mk2 underlay currently for sale on eBay but not sure how different that would be to the mk3? It may be that I just buy a couple of metres of new generic underlay as @Alasdair1 has suggested and cut to fit underneath the passenger side carpet.

Hello, I had the heater matrix replaced on my 2017 Mk 3.5 Octavia estate at the back end of last year. There had been a month or so of coolant leaking and the heater matrix replacement has fixed the issue. When I’ve gone to clean my car last month, the amount that had actually leaked became apparent and when I lifted the rubber floor mats on the passenger front and rear footwells to vacuum, the carpet and underfelt was soaking. Whilst the carpet is now much drier, I have had a car detailer look at it today to see how they would recommend cleaning. The car detailer said he had seen and repaired this type of issue before, and recommended to get a new underfelt. He demonstrated that the old one was starting to turn to mush and couldn’t really be rescued. I am not very DIY minded when it comes to cars (I can change a tyre and top up liquids!) but the detailer has said he will remove the passenger seat, sills and fit a new underlay for me, before doing a carpet wash and general valet. I just need to find an underfelt (can be second hand). Does anybody have experience of this, and know where I could get underfelt from for this model? Appreciate I will probably have to buy a full underlay and cut to just use passenger side. I am UK based. Thank you.