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There are many reasons why sealing your duct system is important. For example, it can prevent duct leakage and improve your indoor air quality considerably.
However, there are many options when choosing the best products for keeping your ducts sealed tight. Two popular ones are duct mastic and duct tape (or foil tape).
So what are the differences between them, what benefits does each provide, and are there any downsides for picking one over the other?
Duct mastic is a material that you paint over your leaky ducts filling up the gaps. When it dries (after a day or so), the mastic hardens and forms a resistant air barrier. When correctly applied, mastic is an extremely effecitve solution for sealing ducts.
One of the best qualities of mastic is that it doesn't easily deteriorate and instead remains adhesive over time. This permanent solution can last as long as your ducts do!
However, mastic also has disadvantages. The main one is that it can be hard to achieve complete coverage. It might look like you have painted a fap, but that doesn't mean it's necessarily sealed.
It can also be hard to apply the material in crevices and tight cracks, and you might need to move the ducts around to reach difficult areas. Once dry, movement can also cause cracks, which means you will have to re-apply the mastic.
Duct tape (or rather, tape for ducts) is a quicker and relatively easier solution for air duct leakage issues. This option is less messy and can create a strong air seal. However, the one disadvantage of this material is that it tends to lose adhesion over time.
One good alternative to duct tape itself is silver foil tape. This choice tends to be readily available at hardware stores, although the quality varies considerably.
Some foil tapes adhere easily, while others fail quickly. Fiberglass mesh tape is also an excellent option for fixing air ducts. However, one of the main issues with tape, no matter the type, is that it can wrinkle and tear.
In short, tape can be a good, inexpensive solution for leaky ducts. In most cases, however, it's just a matter of time until the adhesive breaks down or the tape wrinkles and you have to re-apply it.
Mastic is a perfect option for sealing your duct system - but it needs to be applied carefully, and it can be messy. It can also be difficult to reach all duct areas, and you will have to be particularly careful when filling in significant gaps, as you don't want mastic inside the ducts.
Tape, on the other hand, can be an affordable and easy-to-apply alternative, but most products will eventually lose adhesion and need replacing.
The tape vs mastic question is not an easy one. However, an HVAC contractor will typically use a combination of duct mastic and duct tape to achieve the perfect seal. An excellent option is mastic tape, which looks like regular foil tape but has mastic-grade adhesive.
It can be tempting to try your luck using mastic and tape over your duct seams, leaks, and cracks. However, it's essential that you pay special attention to the quality of the material and the area surrounding your duct system.
For example, if your pipe ducts have insulation around them, you will have to first unwrap them, then seal the leaks, and lastly, put the insulation back.
You will also have to keep in mind that you might need to maneuver around ductwork in tight spaces, perhaps behind a drywall, installing sheet metal screws, surrounded by attic foam, or in dirty crawlspaces.
Protecting your ductwork is not impossible, but you will get the best results if you hire HVAC contractors that understand the materials and all relevant fittings.
Hawthorne PHC is a plumbing, heating, and cooling company offering checks, repairs, and services. If you are looking for a plumber in Las Vegas, Hawthorne can help you fix and prevent duct leakage and explain the best options for keeping your HVAC system in shape. Request a quote today!