DIY duct sealing can handle small, accessible leaks, but hidden leaks inside walls or crawlspaces usually need a professional to find and seal properly.
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Quick answer: You can safely DIY-seal small, visible duct leaks at accessible joints using foil (not cloth) tape or duct mastic. But most homes have leaks hidden inside walls, floors, or crawlspaces that you can't see or reach, so a full sealing job that actually fixes your comfort and energy bills is usually best left to a professional with the right access and testing tools.
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If you can see and reach a duct joint in your basement, attic, or crawlspace, sealing it yourself is a reasonable weekend project. The key is using the right material: metal-backed foil tape or brush-on duct mastic. Despite the name, actual cloth-backed "duct tape" dries out and peels within a year or two and is not meant for this job.
A licensed CANRO technician can take a look — honest assessment, no pressure.
📞 (604) 359-1081Request a free quoteThe leaks that cost you the most money are usually the ones you can't see: joints buried behind drywall, under insulation, or running through floor joists. Finding those requires either opening up finished areas or using a duct blaster/pressure test to figure out where air is actually escaping. A homeowner sealing only the accessible sections can end up doing real work for only a small fraction of the actual leakage.
A professional duct sealing job typically includes a system-wide inspection, pressure testing to measure how much air is being lost, and sealing at every accessible point rather than just the obvious ones. For older Metro Vancouver homes with crawlspace or attic ductwork, that inspection often turns up disconnected sections or crushed runs that no amount of tape will fix.
If you're dealing with one or two obvious gaps you can reach easily, DIY sealing is fine. If you're chasing rooms that never seem to heat or cool properly, noticing a jump in your energy bill, or you simply can't access most of your ductwork, it's worth having a technician assess the whole system. CANRO can inspect your ducts, pressure test for leaks, and give you a free written quote before any work starts, so you know exactly what you're paying for.
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📞 (604) 359-1081Request a free quoteReviewed by the CANRO Heating & Cooling service team — July 07, 2026. Technical Safety BC gas licence LGA0043870 · boiler licence LBP0046450 · Red Seal certified · WorkSafeBC and liability insured · 4.9★ from 85+ Google reviews · serving Metro Vancouver since 1999 · (604) 359-1081.
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