I am creating a food processing room in part of a shed on our fish farm. The shed is a 40 yr old 4x2 timber frame at 600mm centres with noggins half way. We insulated it and fixed up OSB sheets to create the walls as I thought (wrongly) this would be a better surface to bond the 2.5mm PVC sheets to than plaster board, this is to make it hygienic for food prep. I bought the PVC and adhesive from a company in the NE , and everything went really well. 1 tube of adhesive per 8x4 sheet, we then pressed it on with our palms for a couple of minutes and left it 24hrs to cure before doing the sheet adjacent to it. It went up really well but about 4 weeks later some of the sheets (and now all) have completely detached from the walls and will need to be redone which is soul destroying as it took me many days to do it and to redo it will take longer. I removed one of the sheets carefully from between the joining strips and the adhesive has completely detached from the PVC and 100% bonded to the OSB! see photo ...the PVC sheet has no adhesive at all on it. So I don't know what's happened and have no idea how to fix it. I can't make the same error twice, it'll kill me so does anyone know what's happened and how I can fix it? I should say I did get in touch with the company that supplied the PVC sheets and adhesive but they were unable to shed any light on what happened and suggested i put twice as much adhesive on the walls (2 tubes /sheet) but in my mind it'll be still 100% failure and twice as much to scrape off when it does.