How important is it that the existing surface that I am covering is flat? And are there products that would better suit an uneven surface?

Thanks for your question - this is something we get asked fairly regularly. Yes, I think we have a solution for you. Usually I’d recommend our domestic panel range in this situation (click here to see those panels). However, we always recommend that these panels are fitted to a flat, solid, dry surface. These panels aren’t very well suited to surfaces that are so uneven. A possible solution might be our Proclad 10 panels. This is a 10mm thick white PVC panel ideal for situations where you do not already have a surface suitable for cladding onto, and this thus avoids the need to fit additional plywood or a similar material prior to cladding.