How to wrap ductwork with bubble wrap insulation
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- Опубликовано: 14 окт 2015
- This video shows how to insulate sheet metal duct work with R8.0 bubble wrap insulation. The insulation is called Big Bubble by Reflectix. I show how to make the wrap last for 50 years without unraveling. The key is silver colored 3 inch wide rfoil metalized duct tape. When the duct work is exposed to attic heat, the tape should be covered with UL 181m water based mastic. Reflectix says to use 181p aluminum tape. But, I think the rfoil duct tape with mastic is better.
Here is the link to the insulation: reflectixinc.com/basepage.asp?...
Loose fitting isn’t a uniform airgap. You must use stand-off’s or wrap strips of the bubble every 8-12” for it to be effective.
Though, this will pass inspection.
, a note on installers saying “hey this is code so it is great work.” Not true, code is the minimum “C” standard and inspections are lame. tape plus mastic can be “A” level work if the insulation is done right. R8 bubble is not R8 unless ther is a uniform airgap like this commenter states otherwise it’s effect is more like R1. and inadequate. I’d prefer all taps and joints to be mastic coated and to try to seal the duct. Love that this installer catches the air voids and mentions oxegen causing non coated tape to deteriorate and fail in time.
I thought you needed a 3/4 air gap between the metal and insulation . To get full r-8 value
You need some amount of air gap. 3/4 sounds like too much.
3/4 is what the manufacturer recommends
If you were going to show the "correct way" to apply thermally reflective barrier in any assembly, you MUST have at least 1/4 inch gap between the foil and anything else. Otherwise you do NOT get the extra R2. Your assembly is the rated R6 as you have no defined gap.
I have installed MILES of this stuff in all kinds of specialized situations. Having 1/4 inch MINIMUM air gap can actually exceed the R8.
Check out other vids, wrapping strips around the duct to "stand off" the foil works fairly well. gaps greater than 1/4 inch are even better, just be sure that the foil does not touch the duct.
Agree on all points. I’ve used double strips of the reflectix to act as spacers but I’d love to know if you have found something more suitable / less labor to install for your spacers in such an application. Would 1/2” foam weather stripping (that comes in rolls) work for a spacer? Or do you think the foam would degrade with time?
I am pretty sure you are supposed to wrap strips of bubble wrap around the duct prior to wrapping the duct, this is your air gap. Also, I personally prefer putting the seam down. This way if the tape and or mastic starts going bad, the weight of the duct will keep it wrapped. If you have the seam at the top it will just open up.
A-Team Adam you are 2inch strips
Smart about the seams on bottom.
Great description on the process and the reasoning
That was some nice work. Thanks!
I generally use strips underneath and spray glue with silver metal tape without lettering on it. No problems sweating or coming off. Except the time I used The metal tape with red lettering that Nashua makes. Seal that Dove tail tap! Lol
Nice demo. The bubble wrap is so much more user friendly than fiberglass. I'm in the process of redoing the hack job that was done on my attic ac install. Cold air leaks everywhere.
Excellent video. Kudo's for demonstrating the right way to fabricate and install ductwork. I have seen so many duct jobs that can only be called shoddy at best. Properly sized and installed ductwork can mean the difference between an efficient and long lasting system and one that performs poorly and have a shortened life as a result.
I don't know how many times I've watched this video, i appreciate the info. Something i'd like to pass along is...flex fix 555 tape and it is UL listed, put that in a tape gun and its really nice on bubble wrap. Keep up the good work!
Everone who has posted the need for 3/4 strips underneath to achieve R8 is correct. Wrapping it loosely will only give you R6
Great JOB! Pure Craftsman!
Very good work and tips. thanks.
I have a duct project coming up and I'm glad I found your video. Thanks for all the info.
Is Reflectix good for ductwork?
Ease of handling and quick installation make Reflectix the first choice when selecting insulation for round or rectangular ductwork in HVAC systems. The product provides an R-8.0 when installed with a 0.75” air gap between the duct and the insulation, and R-6.0 when installed direct to the duct without a spacer.
I like the way you work. Great idea with the bubble wrap.
Great video and very nice work. Thanks for sharing.
Nice installation bro!,im ductman from philipines😍
Bubble wrap literally shines from all angles !!!! Good video
Need that air gap with bubble strips in order to achieve the true R-8 rating, per Reflectix. I know there is an element of complacency at play with this stuff but I like to stick to my guns when it comes to product submittals, etc. The rfoil tape with a mastic cover is a great idea. Too many times have I seen traditional foil tape fail to close air gaps on complicated seams such as wyes, sq2rounds, custom fittings, etc. Not a bad idea to use a better tape but still maintain code.
This was very helpful
if you go to the trouble to Mastic your duct insulation seams, why in the world would you not mastic your actual duct seams??? You should be using mastic on all the slip/drive connections as well as the 5 foot snap lock/Pittsburg connections. If you don't do it now, you will be as soon as your local permitting office gets around to requiring duct tightness tests...
I had to insulate over the seams. Mastic would require a day to dry if I used it on the seams. Tape is instant. Also, I did most of the insulating on the floor and then moved the duct to the attic. Mastic will crack when the duct is moved. Tape allows the duct to flex while it is installed in place.
Mastic wont crack when' You move it. Also, If you use the 3/4" strips to provide airspace (needed to achieve R8) it keeps the bubble wrap of off your mastic seems and allows them to dry neatly (although it really doesnt matter if the wrap touches the mastic underneath. If you've masticed the seam well the wrap wont disturb it)
I agree, sealing is even more important than insulating.
Will that make your ductwork more quiet. Mine is noisy
Why did you use duct board collars on metal duct? You didn’t seal the collars either? No scoop or dampers? If you roll the silver over the pink insulation on your flex you won’t have it sticking out. Looks cleaner too.
Great video. I thought you had to have an air gap with the r8 bubble wrap? Another question, do use flex duct to run over your round metal duct for insulation and if so do you use the same size flex duct as the round pipe or do you go one size larger? Thanks.
R8 Flex duct has such a big jacket that it will cover the vent vent boots.
I thought you were supposed to go up one size to get the same cfm and hard pipe. Sometimes that may not be practical. Especially running in between floors
Great video! I have gaps in my ductless cold air return. Can I use mastic over foam seal inside of a cold air return?
thank you for sharing good job excellent video clear and on point ,not a big fan of ductwork but after watching your video I m encouraged thanks again
The listed 181 tape is far superior, you should use it. Also, you didn't achieve R8 on any of this duct, because you didn't use either the corner spacers or the 2" wide strips to create and maintain the air gap. It's ridiculously easy to create the required air gap on rectangular duct, using the spacers made by Reflectix. Too bad you didn't care enough to do it right.
what is the R value of flex duct?
Excellent video.I enjoyed it. Can you tell me how you created the air gap between the duct and the bubble wrap to achieve the R-8? Also do you mastic the joint where the branch round duct connects to the square trunkline? As I did not see the mastic on the takeoff joints. Again really enjoyed the video.
I see that you use Nashua foil tape. I'm looking at their products now and there are so many types. Which one do you use? I know it is not 324. Can you use a cheap duct tape and then cover with mastic? Thanks.
Silver 3” Bubble wrap tape. Nashua 365 72mm RE Michel # 8H297. Alot of guys use silver tape. Duct tape is only 2 inches and will be hard to seam. But, if you can get it to seam, the mastic will lock it down forever.
Silver duct tape will dry out and fall off in 10 or 20 years possibly sooner if in a very hot attic, needing to apply mastic is a step not needed if the correct tape is used. Best to use a UL approved quality aluminum tape and rub the tape on with a plastic spatula provided.
Great video. Thanks for sharing
Nice work!
No spacers?
Can this product be used in a crawlspace or basement?
Yes. It is wet rated. As a matter of fact, one of the first uses for bubble wrap insulation was buried under cement slabs.
when wrapping two peices of insulation side by side do you overlap those peices a little
Nice job. Where do you find that tape?
Bravo
I’m so confused. My ducts in my basement do not have silver foil around the insulation. It’s just a cloth looking fluff wrapped with some kind of yarn and taped with a tan tape. What is this and I’ve been replacing it with fiber glass. But I’m starting to wonder if I’m making the basement less safe to breathe in and will it give me better efficiency on my heating bills? How many different kinds of insulation do they make for hvac ducts and how come mine isn’t metallic? Is it safe to breathe around it?
White paper insulation could be asbestos if it is older than 1980. I like foil fiberglass best.
You dead yet? Sorry no reply
Is it good to use spray glue on the metal before putting the bubble wrap?
No need. Bubble is supposed to have a air gap for better insulation.
How do you seal vapor barrier where the flex duct ties into the main duct?
He didn't
1:31 "That's what she said!" - Michael Scott
Love vids like this, reminds me I'll always have plenty of work lol
Yep. I just did another ductwork job to stay busy. Now it is crazy busy.
@@NathansHVAC He was saying you do shoddy work and their will always be a need to replace or fix it.
Which zebra light are you running?
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You didn't tape and mastic the flex duct junctions
You did not show if the bubble wrap has a ul rating. You showed the fire and spread rating.
Thanks again for another great video. Do you ever work with a helper?
Not very much. Residential is really easy. I usually spend 2 or 3 days on a system change out instead of one. But, it is nice to be able to get parts on the next morning that can't be predicted for the first day. My overhead is 6% of sales as a lone wolf. The industry average is 30%. But, I suppose I could just raise my prices 20% to cover a full time helper. I used to work with a helper when I did commercial and marine. I remember some of the cargo ship a/c repair jobs had 4 helpers to get a decent labor rate. I do have an apprentice right now and we mainly just help each other out when needed. Actually the job in this video was spit up where I did the ductwork and my apprentice did the system. The customer simply paid 2 separate companies. Of course not all customers like that.
Well done. Thank you!
What kind of tape is that again?
Standard aluminum silver tape holds up better than the silver cloth tape I used in this video. Also, use the mastic to stop it from pealing.
@@NathansHVAC thanks. I just used shurtape aluminum and the foil wrap with foam core instead of bubble.
It looks better if you do the end price first
What model number is that tape you use?
good video, thanks!
Only time will tell. I find it hard to believe that smearing mastic over tape whose adhesive is notorious for drying up in a hot attic is going to upgrade the adhesive and fabric to meet UL181. Maybe the mastic will function as tape to hold the insulation in place; only time will tell.
Paul Ohlstein. Been doing this 30 years. The mastic keeps the oxygen off the tape at the edge where the adhesive is exposed.
But do you go back 10 years later to see that the tape is still doing its job?
Paul Ohlstein mastic is ul181
I've yet to see any of the newer duct tapes really dry out all. I've seen some stuff from at least 10 years ago. Give it more time and we'll see. The older stuff around here, most guys used the thinnest cheapest duct tape imaginable. Lol
To measure bubble take pipe size X4 add 1" 1/2 for your lip to tape or mastic.
Thank you sir!
inspirational!
What was the dif between big bubble and quarter inch performance?
The R value is double on the 1 inch bubbles.
of course you have to seal the tab collars, dummy. the tabs leak like a sieve.
What’s actual name and where do I get it?
Sir I am air conditioner duct fitter have vacancy I am experience 15 years Gulf country in Kuwait
I just use a squeegee with my mastic tape never have had a problem with it coming off
Noticed that these trunks aren't cross broken. Are they gonna pop?
+Bob Rosa This was a commercial job. Any popping wouldn't matter anyway. However, I designed the system for low static pressure. Also, since all the branches to the vents are flex, any popping would barely be noticeable. Good point though.
No air gap = the “incorrect” way
all that tape and sealer yet you run 10' lengths of flex and don't tie in & seal those to the trunk insulation?
The flex was nylon tied with 2 ties on each termination. The holes were cut super accurate with the circular hole cutter and didn't need sealing. But, I probably should have sealed them from the inside with mastic.
NathansHVAC i meant the outer silver lining, since you stressed "moisture barrier" on your other connections, but left them completely open here
Kevin Keel moisture barrier is when you use the end of the flex and you push it up tight when you put the final nylon tie. That closes the gap.
NathansHVAC you should seal those tab collars with mastic because even if the hole is cut perfect they will leak. Also, the flex duct will leak too with just zip ties on it. The proper way to do that is to mastic the collar on the outside first, you can use a caulking gun with mastic in a tube if you want, it's less messy. Then, you slide the inner liner of the flex duct about halfway up the collar and tape the inner liner to the collar with UL181 duct tape. Then, I like to mastic over the tape. Not everyone does it, but I like to make sure it's sealed and will never come off. Then, you put a zip tie on the inner liner and tighten it with a panduit gun. Then, you pull the insulation of the flex duct all the way to the trunk line and put a zip tie on the flex about 2 inches away from the trunk line, making a donut shape. Then, you can use the UL181 tape to tape the flex duct to the trunk line and seal over the tape with mastic. But, if the insulation of the flex duct is touching the insulation of the trunk line all the way around, it's not really necessary. When you look at the bottom of your flex duct, you can see pink insulation showing, which looks ugly, and some inspectors will fail you for having insulation showing like that. I've been an HVAC installer and service tech for 15 years so I don't know what I'm talking about. For the most part, your job looks good, but you need to seal your runs better.
I meant I do know what I'm talking about, lol.
You have no dampers in them collars you asking for trouble the dampers actually work as a scoop when they open
Where is your squeegee?
I usually just use my gloves. Does squeegee make a difference? I never get ul181 to stick well. So i use plain silver tape.
@@NathansHVAC yes, the squeegee insures a better bond.