My 2020 Chausson came with a ‘treated’ duckboard in our shower tray. There was no guidance on whether to remove it when showering, but we did remove it - as the timber only had a wood preservative treatment. I have recently given it 4 coats of external yacht gloss varnish, so as well as being well ‘proofed’ it looks great. We will leave it in when showering from now on. I also fitted around 20 small rubber feet to avoid the timber marks which were developing on the tray, and this helps to distribute the weight across the whole shower tray.