That contractor who told me to skip the vapor barrier under my deck

Last spring I was framing a deck for a homeowner in Arlington and this guy who called himself a handyman comes over from next door. He said I was wasting money putting down a vapor barrier under the deck boards because rainwater just drains through the gaps anyway. I told him politely that was wrong but he kept arguing, saying I was overengineering a simple project. Three months later his neighbor called me to fix his deck boards that were cupping and rotting from moisture wicking up from the ground underneath. That one conversation cost that guy probably $1,200 in replacement lumber and labor. Has anyone else run into a neighbor or friend who gave terrible advice that ended up costing you time or cash?

3 comments

3 Comments

sanchez.ivan2d ago

Holy cow, you've got a neighbor out there just raw dogging his deck with no vapor barrier and hoping for the best? And he said it was holding up better? That's wild.

kevinw943d ago

Nah man you're overthinking it... vapor barriers under decks are basically just a way to trap moisture against the wood if you don't have perfect air flow. That handyman might've been onto something if the deck was built right in the first place.

sanchez.ivan3d ago

Wait, is that why my neighbor's deck started rotting from underneath just two years after he built it? He put that plastic sheeting down, thought he was being smart. Then he spent a whole weekend pulling it all back up cause water was just sitting there like a swimming pool. He said the wood underneath looked like a wet sponge. Now he just leaves the underside open. Lets the air do its thing. Seems to be holding up better, but I dunno, maybe his dirt grade is just different from yours.