Need help with flooring of my in home greenhouse

[mgmine]

I have not used the PVC lining but can tell you that the 45 mill rubber is very strong and should last for years. here is a link to one place but a search will turn up a lot more. You may be able to get it locally at a garden store or pond store.
http://www.webbsonline.com/Category/pond-liners-epdm-45mil-underlay