Skylight Glass Replacement

A skylight IGU lives a harder life than any vertical window in your house. It faces the sun at a near-perpendicular angle for hours a day, sits directly above an attic or vaulted ceiling that can hit 140°F in a New Jersey July, and then gets buried under snow in January. That thermal cycling — glass surface swinging through huge temperature ranges, dozens of freeze-thaw cycles every NJ winter — works the perimeter seal of the insulated unit far harder than a wall window ever experiences. When the seal fatigues, the argon fill migrates out, humid air migrates in, and you get the permanent fog or milky haze between the panes that no cleaning will touch.

Slope makes it worse. Rain and snowmelt shed off a vertical window almost instantly; on a low-slope skylight, water sits on the glass and against the edge seal for hours. A perimeter seal that stays wet ages faster, which is why we see skylight IGUs fail years earlier than the wall windows installed in the same house at the same time. Fog that appears on cold mornings and clears by afternoon is the early stage; it always progresses to permanent haze and mineral staining between the panes.

Then there's impact. New Jersey's severe summer thunderstorms drop hail, and nor'easters drop branches. A properly built skylight takes the hit on its tempered outer pane, which crumbles into small pebbles instead of daggers, while the laminated inner pane holds everything overhead — nothing rains down into your kitchen. If your skylight cracked and held together in a spiderweb pattern, that's the laminated layer doing its job. Either way, a cracked pane means the sealed unit is done and needs to be replaced as a unit.

Glass over your head is regulated differently than glass in your walls. New Jersey adopts the International Residential Code through its Uniform Construction Code at N.J.A.C. 5:23, and IRC Section R308.6 governs skylights and sloped glazing: overhead glass must be laminated, fully tempered, heat-strengthened, or wired glass — plain annealed float glass is prohibited. And where tempered or heat-strengthened glass is used overhead, the code adds retention requirements so that broken glass can't fall on occupants, which in practice means either a screen installed below the glazing or a laminated pane on the room side.

That's why the standard make-up for a modern residential skylight IGU is tempered glass outboard and laminated glass inboard. The tempered outer pane resists hail, snow load, and debris; the laminated inner pane — two lites bonded to a PVB interlayer — stays in the frame even if it cracks, satisfying the retention requirement without an ugly screen under your skylight. This is the spec the major skylight manufacturers ship as standard, and it's the spec we fabricate to. It's also the detail that separates a proper skylight glass replacement from a generic glass swap: a plain dual-tempered unit dropped into an overhead opening can be a code violation and a genuine hazard.

Replacement is also the moment to upgrade the energy spec. Most failed skylight units are 15-25 years old, pre-dating modern coatings. A new unit with a current Low-E coating, argon fill, and a warm-edge spacer cuts the heat a south-facing skylight dumps into the room in summer, reduces winter condensation on the glass, and slows UV fading of floors and furniture below — all inside the same frame you already own.

This is the most important diagnosis in skylight work, and it decides which company you need. Moisture or fog trapped between the two panes of glass — visible haze you can't wipe from either side — is IGU seal failure. That's a glass problem, it's our scope, and the fix is a new sealed unit in your existing frame. Water on the ceiling around the skylight is a different animal: stains at the drywall corners of the skylight well, drips that show up during wind-driven rain or after snow sits on the roof, or leaks that trace back to an ice dam are almost always flashing, underlayment, or curb problems — roof-side failures that new glass will not fix.

There's a third case that fools everyone: condensation. In winter, warm humid indoor air rises into the skylight well, hits the coldest glass surface in the house, condenses, and drips off the frame onto the floor. It looks exactly like a leak, but the roof is bone dry. The fix there is humidity control and, in stubborn cases, upgrading to a warmer glass package — a modern Low-E unit with a warm-edge spacer keeps the interior pane warm enough that condensation stops forming. We check for this pattern before anyone starts pulling flashing apart.

When we inspect and the water path traces to flashing or the curb, we hand you directly to our sister brand, Precision Roofing NJ (precisionroofingnj.com), who handle skylight flashing kits, curb rebuilds, and roof integration. When it's both — a fogged unit and tired flashing — the two crews coordinate so the glass and the roof work are sequenced correctly and you're not paying for two separate mobilizations blind.

Glass-only replacement is the right call when the skylight frame and curb are structurally sound and the glazing system is serviceable — which covers the majority of deck-mounted and curb-mounted units from Velux and similar manufacturers, plus most site-built curb skylights on flat and low-slope roofs. We remove the glazing cap or retaining gaskets, lift out the failed unit, and set the new one on fresh setting blocks with new gaskets and sealant. Your interior finishes, the roof membrane, and the flashing are never disturbed, and the skylight you already paid for keeps working for another couple of decades.

Full skylight replacement is the honest answer when the curb or frame is rotted, the frame cladding has failed, the model is so old the frame can't reliably retain a new IGU, or you're re-roofing anyway — if a roof replacement is on the horizon, replacing tired skylights during the re-roof is the smart sequence, because the flashing gets done once. Full replacement means opening the roof, and that's a Precision Roofing NJ scope, not ours. We'll tell you plainly which situation you're in; we don't sell glass into a rotted curb.

Either way, the process starts the same: a free on-site assessment. We measure, we diagnose, we put the recommendation and the exact glass specification in a written quote, and nothing gets fabricated or scheduled until you've approved it.