Duct insulation guide
Duct Insulation Fasteners vs Pins vs Tie Wire vs Tape
Duct wrap has to be held on, not just sealed. Here is how the common ways of attaching duct insulation compare on the job: what they need, how they hold, and how fast they go.
Start with what the manufacturers say
Owens Corning, Johns Manville and Knauf all call for mechanical fasteners in their duct insulation installation instructions. Tape has a job, sealing the seams and the vapor barrier, but it is not the thing holding the insulation to the duct.
The four common methods
Tape alone
Fast to apply and already on the truck. But tape is a sealant, and an adhesive bond can let go as temperatures swing. When it does, the insulation sags and the job becomes a callback.
Tie wire
A mechanical hold, but slow: wrap, twist, cut, repeat, around every section of duct. It is hard on hands and harder to keep tight.
Stick pins and weld pins
Adhesive-base pins depend on an adhesive bond to the duct, which can soften in heat. Weld pins hold well but need a welding gun and power on site.
Mechanical disc fasteners
A disc goes over a sheet metal screw and is driven through the insulation into the duct with a drill. The hold is mechanical, so it does not depend on an adhesive.
Side by side
| Tape | Tie wire | Adhesive pins | Zip-Ez™ | |
|---|---|---|---|---|
| How it holds | Adhesive | Wire around the duct | Adhesive base | Screw, mechanical |
| Tools | None | Pliers, cutters | None | Your drill |
| Heat and cold | Bond can fail | Holds | Bond can soften | Holds |
| Speed | Fast | Slow | Moderate | At least 2x tie wire |
| Reusable on a rewrap | No | No | No | Yes |
How Zip-Ez™ goes in
- Slip a Zip-Ez™ disc over a sheet metal screw (we use a #8 x 1 in hex washer-head self-drilling screw, not included).
- Position it over the overlapping edge of the duct wrap or foam board.
- Drive it through with your drill. One per foot.
In April 2010 an independent BPI-certified HERS rater tested Zip-Ez™ with a Minneapolis Duct Blaster and measured zero air leakage at the fastener penetration points. Read the test report.
Approximately 250 per bag. Works on duct wrap, fiberglass duct insulation, bubble reflective insulation and rigid foam board. Patented design, made in the USA.
Questions
Do insulation manufacturers require mechanical fasteners?
Owens Corning, Johns Manville and Knauf all call for mechanical fasteners in their duct insulation installation instructions, including on the underside of wider rectangular duct.
How many fasteners per foot?
With Zip-Ez™, one per foot along the insulation overlap.
Is tape enough on its own?
Tape seals seams and vapor barriers. It is not meant to be what holds the insulation onto the duct.