Hvac -gas venting

[Doug welborn]

The gas heating unit was in the basement, the first 5 feet was double wall pipe and then it went into a single wall pipe. Am I

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108.09 KBcorrect that it should be double wall pipe through the floor, walls, and ceiling. Thanks Doug.

[msteger]

What sort of clearance to combustibles existed from what you can tell? I can't imagine enough clearance exists above this area. I would have done double wall (B) the entire length.

What's that 'expandable foam' stuff on the connector pipe? Looks weird to me.

[Bain]

You have to install a B-vent in unconditioned areas.

I'm constantly amazed by the many uses homeowners--and some builders--find for Great Stuff foam. I recently had a call from a builder who said, "But wait. Read the can. It is rated for exterior use if you coat it with polyurethane."

I reminded him that there was no poly on the ugly gobs of yellow pus oozing out of his shiny new house.

"Well, no," he said. "We haven't gotten around to it yet."