Well, yes, BUT.......... Be sure to use the correct tape - Duct tape ("Duck Tape") is no good - neither is the wafer thin silver tape. You need a good quality mastic-backed tape to be at all effective. And make sure it covers and extends beyond the edges of the contractor's tape.

You realize you'll likely piss the guy off?

"You realize you'll likely piss the guy off?"

LOL. Yea, probably. But I think they are done and wont be back until the ducts are all covered up.

Pissing sub contractors off is an unfortunate side effect of wanting my house to be as well insulated and comfortable as my budget, time and technology allow. The subs think nothing off cutting a hole in the exterior sheathing, running their vent, cable or copper pipe to the outside and then putting the fiberglass insulation back in place. No spray foam or other attempt to seal up the gaps around the hole they cut. I have been going in one weekends and foaming all those openings (and more). I actually paid the insulation sub to do a couple of extra things for me but because they did not understand why they were doing those things, they did them in a way that didn't accomplish my goals.

Anyway, tell me why you think it's worth the time and energy to tighten up the standard duct sealing work that my HVAC sub did. What they would say is "your ducts are all inside the conditioned envelope of the home, so it doesnt matter if they leak."

Can you recommend a tape that would work well?

What they would say is "your ducts are all inside the conditioned envelope of the home, so it doesnt matter if they leak."

It isn't near as determinal as would be if ducts ran through unconditioned space. Returns should be sealed tight as possible regardless of where they are located and here's why. Air entering return always carry's dirt with it. Not much harm result's if dirt enter's BEFORE filter but will eventually clog coils if it enter's AFTER filter. A good reason to retape ducts is to get a longer lasting tape on it because if tape peel's off over time it can cause enough leaks to throw system out of balance. Another reason for good tape is that if part of area is later converted to unconditioned storage or mechanical room. If ducts were covered behind drywall and tape was peeling,that could be a problem. The main reason what you are doing is ok and shouldn't upset anyone is "your house,your time,your money and it make's you feel better."

The tape that I have easy access to is Nashua foil tape. I think it's this one tape. I used it (or similar) on the house we built 9 years ago and the tape is still well adhered.

The furnace filter is just a few inches from the blower and I think they sealed that case up pretty well. If not, it's not getting covered with drywall so I can always fix that after closing. My focus is those areas that are going to get covered up - preventing me from fixing them later.

I assume that leaky supply and return ducts running next to each other in an enclosed space (sheet rocked basement ceiling) are going to allow the air to travel from supply to return without ever reaching their ultimate destination. So rather that heating a distant room they will be heating the enclosed space between the basement ceiling and subfloor. Does that logic makes sense?

Another question ... I have a spray foam gun and have gotten pretty good with it. Assuming that I keep the foam from entering and blocking a duct, is there any reason that I cant put a dollop here and there if I can reach with the tape?

The advantage of sealing the ducts in a finished basement is that YOU control the air distribution, not the leaks. If you want warm air in the basement install a couple of supply vents and dampers that can be closed off when you don't want the basement heated.

So i spent 5 hrs and 2 rolls of tape on my ducts today. I taped everything i could see and reach. Mostly supply take off fitings. None of those were sealed. Unfortunately theres a lot that i cant see or reach. May try again with mastic on a long brush. That will extend my reach some.

The nashua tape may not be great but it is better than what my sub used. I can pull the subs tape off and put it back. Cant do that with the Nashua foil tape.

What you want to use is Hardcast mastic tape, 1402. Or mastic itself. Available from Ferguson supply.

So what if you piss him off? You're paying him. Tell you you expect better quality and better materials than you've found.

Leak and duct testing is required by code in my area for all new and replacement HVAC installs.

If I piss anybody off I would tell the truth: that they are building my house to the minimum standards contained in the building code. I want something more than that. And truthfully the sub would have zero interest in paying a guy to spend a day at my house doing more air sealing. There's almost no profit in that for him.

Code here will require that ducts be tested for permits pulled after October 2016. Mine was issued right before that - so no testing for my ducts.

You can have duct testing done if you want to. I'm not sure if you're suggesting that the minimum standards, cut the corner approach is what you've contracted for or perhaps even what you directed but you get what you're pay for and don't get what you don't pay for. If you're using a sub who isn't interested in or required to do an adequate job, you'll likely have more problems ahead than just leaky ducts.

This is a tract home. We will likely be in it 10-15 years. We have a standard contract to buy the house once it is completed. The contract basically states that the house will be constructed consistent with the building code and with the Central NY Home Builder's Association Standards of Performance.

I'm not sure what the code says but I know that it does not require duct testing. I doubt that it requires that every seem be taped but maybe it does. The inspectors in this town are considered to be very tough and the sub contractor is a large well established outfit that does a lot of work in town so I assume that the sealing is sufficient to meet code. The Home Builders Standards of Performance document does not refer to duct sealing at all.

None of that surprises me. You get what you pay for and 99% of people will never think twice about the things behind the wall that they cant see. If a room is cold they will turn up the heat or put on a sweater. I know that this stuff could be done better - which in a lot of ways is a curse.

My experience from building 3 previous new homes is that when it comes to insulation, air sealing and duct sealing the contractors are not going to do it to my satisfaction. Even when I pay extra for it. Either they dont know what/how to do it or by the time it gets communicated to the guy in the field it gets lost in translation.

So I follow behind them with a case of spray foam and a "pro" gun, caulk, tape and extra insulation. This has caused problems with contractors in the past but I get a house that is closer to the one I want. Works for me.

I don't use the expensive foil tape and it works fine. IMO the mastic tape is more for an exterior or attic solution due to the extreme temps, gives it a bit more bond. Personally have not had a problem with the standard foil tape. I have had to try to remove some here and there and its quite the ordeal to remove sometimes. Obviously doesn't stick to dust so just clean dust off old runs first (not a problem in your case as its new). Sealing the connection points male and female) are more important, I don't notice leaks in the long seams. Would need super high pressure for that.

Mastic is good for irregular items, like take offs.

Glad you are putting in the effort to seal things up well. It does make a difference. If it is a place where tape, mastic, or foam isn't appropriate, you can use the duct seal compound stuff, it is a putty consistency and very sticky although removable if needed.

There is a supply take off that i cant reach. Thinking about using my foam gun with a piece of hose as an extension. See any problem with that?

"Personally have not had a problem with the standard foil tape."

As part of an equipment replacement project, I just had a duct sealing job done by one of the best-regarded contractors in my area. They used mastic tape in places where they didn't use mastic itself. Are you suggesting you're right and they're wrong?

I used the nashua foil tape ($6) on the new ducts in my last basement 9 years ago and it is still in perfect shape. That's good enough for my needs.

"I'm not sure what the code says but I know that it does not require duct testing. I doubt that it requires that every seem be taped but maybe it does. "

Pretty much every code in effect that I'm aware of requires that leakage be less than a certain percentage (eg 5%). But if no such code exists then contractors/subs can get away with almost anything.

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.

I would feel lucky that the builder even allows you on site to do the sealing work. Many tract home builders require you to sign an agreement that you will only be on site at certain times, and there are significant restrictions on doing your own work.

When the topic is discussed, the builders all have stories about Harry Homeowner adding something that caused a house to fail inspection, so now they don't let Harry on site unless fully supervised.

Bruce

"I would feel lucky that the builder even allows you on site to do the sealing work."

I do.

"Elmer I suggest it doesn't really matter, the foil sticks fine to the metal and seals it just as fine."

You too know better than licensed and experienced HVAC contractors?

LOL, if you really need some backtalk, do you think all HVAC contractors agree on everything and don't have different opinions?

I don't know everything. Neither do you. Both ways work for metal pipe, you can gripe about it all you want but it wont change anything.

I am very happy with how the nashua foil tape adheres to my new metal ducts. And like i said it is still doing its job 9 yrs after being applied to new ducts in my last house.

Alright,enough already. You asked for advise and got it,not based on 9 years and a single home but rather decades and countless homes by multiple people. If you choose to ignore the advise,I said it once and will repeat it,your home,your time your choice but is it really necessary to keep waving your defiance like a school banner? Your behavior might lead people to believe you are more interested in pestering the builder than improving the house?

Impressive how a discussion of duct sealing can turn into something else. Thanks for the advice. Have a wonderful new years.