Ductwork Pasadena: Properly Seal Ductwork with Mastic and Mesh Tape
Many homeowners take their HVAC air ducts for granted. Yet, this ductwork plays a vital role in delivering conditioned air throughout their homes and bringing “used” air back to their furnace, A/C or heat pump. In many homes, either because of poor installation or maintenance, or from the ravages of time, leaks in ductwork can result in a significant loss of conditioned air into unconditioned areas.
These leaks force HVAC systems to work harder to compensate for lost air. This is why it’s important to know some ductwork sealing basics. While you’ll want a qualified professional to perform any comprehensive duct sealing, it’s not a difficult matter to seal accessible ducts yourself, using mastic sealant and mesh tape.
Mastic sealant is a gummy, sticky material, coming in a variety of types. According to most experts, UL 181-rated mastic is the best option to seal ductwork. It’s flexible, sticks to ducts better and lasts longer than other types of sealant.
How to Apply Dust Mastic
- First, wipe off any dust and dirt from the joint between duct sections to ensure a tight seal.
- Then, apply sufficient mastic to form an uninterrupted coating on the duct end. A brush, trowel, caulking gun or even a gloved hand can be used.
- Make sure the joint area has been wiped clean to remove particles and dust before applying the mastic. If the joint isn’t clean, the mastic won’t create a tight seal.
- Next, push the sealant into the crack or joint with a delicate touch to accomplish an even coating.
- The mesh or metal-backed tape should be used to reinforce mastic-coated areas where the gap is larger than a quarter inch. If the area of application will be stressed by weight or movement, you’ll want to use some extra tape. Avoid using common duct tape for these jobs, since it won’t last.
Our goal is to help educate our customers in the Pasadena, California area about energy and home comfort issues (specific to HVAC systems).
Credit/Copyright Attribution: “Kichigan/Shutterstock”