The duct insulation I want to have installed is in 5ft. by 25ft. rolls. It has a reinforced foil face and is a 2" cotton based product.
I had a tech comment that it would be very difficult to install. Am i missing something here, why would it be any more difficult than fiberglass?
Would you not just measure the circumfrance of the metal duct, cut it with a slight overlap on the foil facing and duct tape? Is duct tape good enough for this purpose or should I be requesting some other kind of product at the seams?
Any insight would be great.
Mastic would be better.
Originally Posted by mlo1
Dash, mastic over the seams of the insulations foil face?
Originally Posted by dash
What about keeping the insulation wrapped around the ducts while the mastic is setting-up?
Seal the ducts with mastic, wrap with insulation, staple the flap, then tape the seams in the insulation with UL181 listed foil tape, butyl tape(roll mastic), or film tape.
You could use mastic on the insulation, but man what potential for mess, lol.
The gray/black stuff that is commonly referred to as "duct tape", has no place in or on a HVAC system.
This is a PITA job even with fiberglass. It's bad enough getting FG to stay and cutting correctly for elbows and Ts. I've seen jobs where people tied ropes around the insulation because it started to fall off after a couple of years.
Now you're compounding the difficulty by wanting to use 2" cotton. I've never used it, but my guess is that it's pretty heavy, and will retain moisture a lot more, causing your metal ducts to rust out, and creating a great place for mold to grow.
If you already bought this stuff, then install it yourself, and you'll find out just how easy/hard it is. If you find a tech willing to install it, pay him by the hour and don't ask for a guarantee. If you want a guarantee, ask the manufacturer for a list of recommended installers.
If you don't already have the insulation, then spray foam the ducts. Although expensive, if it's in an area rarely seen, you're much better off.