A handy homeowner can lay plastic in a small, dry, easy-to-reach crawl space. But a crawl space vapour barrier job is better left to a professional if the space is damp, has standing water or smells musty, if there’s old insulation, rodent activity or possible vermiculite, or if you want the walls insulated at the same time. DIY insulation also doesn’t qualify for BC rebates. Find out when to hire a pro for a crawl space vapour barrier.