I forgot to mention, when you're doing any renovation or upgrade, think about what opportunities the project will afford. For me, this is a great time to seal the registers to the subfloor. My registers are not bad, considering some of the installations I've seen. Some people have good size gaps around their register boots. What happens when there is a gap, whether the register is in the ceiling or the floor, is as the air flows out of the register, it sucks air from the crawl space or the attic into your living space. When the system isn't blowing, it simply allows free movement of convective currents.
To seal, I'm using "duct butter" or mastic. This product is also available in a caulk type tube form. Be very careful to mask off the area around the boots if you don't want it ruined by the mastic. This stuff will not come off!!!
I'll also be on the look out for gaps around piping as I continue this job.
Episode 315 – Out of the Clamps
4 hours ago