From the BuildingEnergy 13 Demonstration stages, this is "Duct Sealing". Visit www.nesea.org/buildingenergy for more. Video credit to Green Building Advisor
Agreed on the importance of the return ducts. My basement had massive leaks in the return. I think this likely makes for an inefficient home. Effectively pressurizing upper floors, and creating a vacuum in the basement. This means basement air has to come from other places (like pulled in through rim joist leaks and whatnot).
Thanks for some excellent advice. I'm doing my house, so I'll add a suggestion, one that's perhaps the easiest improvement to make. Remove the louvers on your vents, and you're likely to discover cracks between the ductwork and your ceiling that leaks heated/cooled air into your attic or crawl space. That's easily sealed with the aluminum tape. At the same time, you can also use mastic to seal seams in the ductwork from the inside. Also, if you've got white, blown-in insulation, look for dirty areas. That's a good clue you've got an air leak needing sealing.
Sealing ductwork means to make it airtight as you possibly can. With that in mind, every seam, including longitudinal seams should be sealed as well. I prefer using mastic paste. if there is a large gap, I use fiberglass tape to bridge the gap and multiple coats of Mastic to ensure an Airtight seal. This air tightness needs to include the registers at the floor, ceiling and if needed the walls.
is it safe to use mastic duck sealant inside the filter rack? Our technician used mastic sealant inside the filter rack but used a lot of it to seal holes that he accidentally created.
I saw some using a fiber type of tape like drywall tape to make a stronger bond. My question is how do I seal a leak on the bottom that is not accessible from the outside? Should I take the box apart and seal it from the inside?
I have a square/rectangular return air duct in my attic and I believe that it's sucking attic dust/fiberglass insulation particles into our home and causing our allergies to become inflamed. It's around 15' - 20' in length and not something I feel comfortable pulling out to tape. The main reason why is I dread trying to refit it back to everything that it is attached to as it has a few intakes that it's attached to. The duct sits between two joists that run alongside it so I cannot get mastic or tape on the sides and bottom. Can I just cover the venting w/ plywood, attaching it from joist to joist so it stops sucking in fiberglass insulation particles and dust? I figure I could put some type of gasket sealer between the plywood and joists to prevent air from getting vacuumed in.
What is one-eight? Is is eighteen, or one-point-eight? The number we are all interested in, the reduction from eighty-three, or should I say eight-three, and you say "one-eight"?
No. It’s so trivial. The air itself will be louder than any bumps or peaks. If that were true you could argue that any screw use for joining fittings at any part of the duct system including screws from hangers
The mastic sealant shown, it’s not easy to buy. HVAC supply stores won’t sell it to home owners in Fresno, California. So this video is mute. Does anyone have a buying strategy for this ul rated mastic? Thanks
I am sealing all the ducts of a 9 ton system in my attic in Houston. It’s a lot of work but I cannot believe all the air holes the HVAC people left. They should lose their license for doing such poor work. I’m tapping all the joints heavily and then applying a thick coat of mastic. Then R8 duct wrap.
@@bellsback a huge difference. Not that i purchased a 1975 house so the leaks were massive and the insulation was mostly vanished. I also changed out and air sealed over 50 can lights and all the AC duct return boxes.
@@bellsback I purchased the recessed lights for being buried under insulation, then caulked them with fire foam all around. The body of these are air sealed so you just have to seal around the base.
@@MrCbrehaut This may be my issue! New HVAC installed 3 months ago and ever since the install my indoor air quality is horrible. Today I found several small screw holes in my ducts near the furnace. Holes in the return too. And I feel air leaking in the duct attached above the coil. I asked the HVAC tech about the air leak and he said it was no big deal. Huh. BS, methinks.
Why would you apply mastic with gloves that's the most sloppy messy shit 've ever seen. I've been doing AC and heating for 16 years I've never seen anybody use gloves to apply duct sealer
It's works decent. I just think it makes the work look like shit. I believe tape looks alot better. But before some douchebag comments and thinks I'm dissing the product I'm not. I do installs. I just don't like the looks of it. When you have an install and your metal work looks great, this just ruins it imo.
I hand apply mastic with rubber gloves. It looks bad but it's quick and allows me to get every area with a thick coat. I put on insulation after so you can't see how messy it looks. :P
Agreed on the importance of the return ducts.
My basement had massive leaks in the return. I think this likely makes for an inefficient home. Effectively pressurizing upper floors, and creating a vacuum in the basement. This means basement air has to come from other places (like pulled in through rim joist leaks and whatnot).
Thanks for some excellent advice. I'm doing my house, so I'll add a suggestion, one that's perhaps the easiest improvement to make. Remove the louvers on your vents, and you're likely to discover cracks between the ductwork and your ceiling that leaks heated/cooled air into your attic or crawl space. That's easily sealed with the aluminum tape. At the same time, you can also use mastic to seal seams in the ductwork from the inside.
Also, if you've got white, blown-in insulation, look for dirty areas. That's a good clue you've got an air leak needing sealing.
Sealing ductwork means to make it airtight as you possibly can. With that in mind, every seam, including longitudinal seams should be sealed as well. I prefer using mastic paste. if there is a large gap, I use fiberglass tape to bridge the gap and multiple coats of Mastic to ensure an Airtight seal. This air tightness needs to include the registers at the floor, ceiling and if needed the walls.
Very Informative, thanks
is it safe to use mastic duck sealant inside the filter rack? Our technician used mastic sealant inside the filter rack but used a lot of it to seal holes that he accidentally created.
I saw some using a fiber type of tape like drywall tape to make a stronger bond. My question is how do I seal a leak on the bottom that is not accessible from the outside? Should I take the box apart and seal it from the inside?
If you use the tape do you need to come out past the tape edge with the mastic to make sure the tape does t come up.
I have a square/rectangular return air duct in my attic and I believe that it's sucking attic dust/fiberglass insulation particles into our home and causing our allergies to become inflamed. It's around 15' - 20' in length and not something I feel comfortable pulling out to tape. The main reason why is I dread trying to refit it back to everything that it is attached to as it has a few intakes that it's attached to.
The duct sits between two joists that run alongside it so I cannot get mastic or tape on the sides and bottom. Can I just cover the venting w/ plywood, attaching it from joist to joist so it stops sucking in fiberglass insulation particles and dust? I figure I could put some type of gasket sealer between the plywood and joists to prevent air from getting vacuumed in.
It looks easy that way, make it right with frames 2×4 studs up an down tight spaces
Thought I was watching who’s line is it anyway
What is one-eight? Is is eighteen, or one-point-eight? The number we are all interested in, the reduction from eighty-three, or should I say eight-three, and you say "one-eight"?
What is the brand name of the tape?
do you have to seal the furnace as well? I have an amana 97% efficiency furnace I just bought in 2017.
That rating is gas to heat efficiency not air sealed efficiency.
By using mastic inside the duct don’t you create more air friction? Any bumps or peaks may create a whistling when air passes through?
DebraLynnP
Clever
there would be more noise from leaky ducts as air passes out creating the whistle sounds..and many are insulated which acts as sound barriers also
No. It’s so trivial. The air itself will be louder than any bumps or peaks. If that were true you could argue that any screw use for joining fittings at any part of the duct system including screws from hangers
True story. That's like insulation inside duct work. It also catches anything that happens to get in the stream.
The mastic sealant shown, it’s not easy to buy. HVAC supply stores won’t sell it to home owners in Fresno, California. So this video is mute. Does anyone have a buying strategy for this ul rated mastic? Thanks
Amazon
i have a small doubt about sealing?
this sealing is fire resistance or not?
suman s
It is, at least the stuff used in the commercial world.
You need a brush to use the duct seal that's what im use paint brush.
I am sealing all the ducts of a 9 ton system in my attic in Houston. It’s a lot of work but I cannot believe all the air holes the HVAC people left. They should lose their license for doing such poor work. I’m tapping all the joints heavily and then applying a thick coat of mastic. Then R8 duct wrap.
Depending on local codes it isn't required and unless a contractor bids the sealing it won't be done.
Because most HVAC people are lazy AF and don't give a shit about efficiency
@@bellsback a huge difference. Not that i purchased a 1975 house so the leaks were massive and the insulation was mostly vanished. I also changed out and air sealed over 50 can lights and all the AC duct return boxes.
@@bellsback I purchased the recessed lights for being buried under insulation, then caulked them with fire foam all around. The body of these are air sealed so you just have to seal around the base.
@@MrCbrehaut This may be my issue! New HVAC installed 3 months ago and ever since the install my indoor air quality is horrible. Today I found several small screw holes in my ducts near the furnace. Holes in the return too. And I feel air leaking in the duct attached above the coil. I asked the HVAC tech about the air leak and he said it was no big deal. Huh. BS, methinks.
Looks more like a ductasaurus.
gotta use a chip.brush
Spray all your plywood walls so house is real tight then go buy an air exchanger and change the air in your home .3 air changes per hour lmao
Legit
1> COAT 2 >FIBER MESH 3 >COAT
Why would you apply mastic with gloves that's the most sloppy messy shit 've ever seen.
I've been doing AC and heating for 16 years I've never seen anybody use gloves to apply duct sealer
skinnybeats 420 lmfao. Get a brush lol. My duct sealing looks beautiful when I’m done. It looks like that dog shit himself
2" chip brush works well. I was shocked by the hand use too. What a mess. Haha.
M
This was 6 years ago sorry we are prob all living underground now.
I WOULDN'T LIKE TO DO THAT ITS SO NASTY Y PREFER THE BRUSH
AND DO IT ORDERLY
I thought so too, but after trying it with rubber gloves it's quicker and you can get into areas that you can't reach with a brush.
@@rosemcommm its makes it sloppy. I've had no issues with a brush before
@@travissturm2531 Just depends on the situation. Mine was already installed and in a crawlspace.
It's works decent. I just think it makes the work look like shit. I believe tape looks alot better. But before some douchebag comments and thinks I'm dissing the product I'm not. I do installs. I just don't like the looks of it. When you have an install and your metal work looks great, this just ruins it imo.
I hand apply mastic with rubber gloves. It looks bad but it's quick and allows me to get every area with a thick coat. I put on insulation after so you can't see how messy it looks. :P
I wish I had a dollar for each "um" he said. Otherwise a good informational video. Thanks
Good information, good equipment, poor presentation
What a f.... mess!
Is it possible to take someone who wears sunglasses on their head while doing a seminar serious?
dont knock it 10 years in the biz, he is knowledgable
Wooow how many buckets this people need lol my son can mastic better
Why are they using there hands?use a brush. These folks must be on the spectrum
My guess is it makes the mastic application more compact when you apply it with hands compared to a brush.
@@Tasty_sand I work in hvac and I just dump it on the seam with the brush. I've never seen anybody just stick there glove in
Would never use a glove, good way to slice your hands up.
Get to the point 🤦🏻♂️ & try to keep your video’s short & simple
How did i get here? Time for bed.