had to google ptcs Performance Tested Comfort Systems PTCS Certification is an important qualification for contractors working on HVAC systems such as furnaces, air conditioners, heat pumps, and ventilation ducts. PTCS certified contractors are trained � and held accountable through third-party inspections � to evaluate your entire house as a system when installing a new HVAC system. In many cases, you may be able to replace your existing furnace, air conditioner or heat pump with a smaller (and cheaper) unit if the installation is accompanied by air sealing, insulation, duct sealing and other efficiency measures. The program is limited to the Pacific Northwest, including Washington, Oregon, Montana and Idaho. If you live in one of those four states, you should look for the PTCS Certification when evaluating a contractor to do any HVAC work for your house. ___________________________________________________________ ok enough of that pic by pic comments: Pic 1 hard pipe supply plenum (silver) with black flex suppy duct see the failure of the duct tape? the duct tape should be removed. black jacket and insulation folded back and take off mastic sealed to hard pipe plenum. not only the take off but also the inner liner of duct to take off. let dry. insulation and jacket pulled to plenum in full contact and mastic sealed. I would use paint on mastic for the seal to the plenum and mastic tape to secure jacket to ductwrap of plenum. pic 2 & 3 see above pic 4 your vapor barrier should extend up on the walls of the crawlspace and be sealed to walls pic 4 this is where the hard duct plenum reduces to smaller size..the joints here leak also. but opening the duct wrap and mastic sealing these areas would be a LOT of work. you may want to seal major leaks first and see if performance improves before tackling the sealing of hard pipe. It is curious that the pipes seem to be insulated with batt insulation rather than pipe insulation see pink insulation wrap on pipe going thru block wall. this may be to condensing unit? so do you think you may take this job on or sub it out? if you sub it out make sure that you have duct leakage numbers before and test to get reduction numbers afte sealing. also take a look at the job in progress to make sure that mastic or mastic tapes are used. best of luck.

You need a plastic vapour barrier OVER a concrete floor? I would have assumed there was a moisture barrier under the concrete, and that would suffice. Where I am, Interior British Columbia, basement floors are bare concrete, and if finished, have carpet and regular underlay, or some sort of hardwood or laminate flooring with some sort of underlayment... but nothing that would really comprise a true vapour barrier. A lot of the time, basement floor formwork is polystyrene, so it's insulated and moisture-proofed at the same time.

If you're going to the trouble and work to finish the job the right way, why even risk not following manufacturer's advice? If you turn on the system before the mastic has cured, you might blow holes through your hard work and negate the benefit you're trying to have. Maybe using a foil mastic-backed tape like Hardcast 1402 could be usable sooner?

Elmer I suggest it doesn't really matter, the foil sticks fine to the metal and seals it just as fine. If you are using a ductboard or something the foil tape doesn't stick to then for sure the mastic tape. Foil tape doesn't stick very well to wood either for another example. So at boots the mastic tape would be better, or just mastic since it is cheaper. Foam would expand and fill gaps, but it doesn't particularly adhere well to metal. Maybe small areas that expanded into gaps would anchor it and keep it there. Not sure. Obviously a last resort sort of idea.