Do all skylights eventually leak? (2025 Update) FAQ

on 2/23/2009 4:13 PM (ET) snipped-for-privacy@ymail.com wrote the following:

Anything penetrating the roof CAN leak, but everything does NOT leak.

On 2/23/2009 1:13 PM snipped-for-privacy@ymail.com spake thus:

The building I live in has skylights in all units, installed at least 20 years ago. Of the two units I've lived in, none of them have leaked (each unit has 1 large fixed and 1 smaller openable skylight). My neighbor's skylight leaked during the last rainstorm, but that's the first leak I've known about in the building. So no, if properly installed and maintained, they shouldn't leak.

Roofs eventually leak.

A lot of what gets called 'leaks', is really condensation on the inside of the skylight dripping down and staining the edges of the opening. Not as much a problem with modern dual-layer bubbles, but dirt-common with the 1960s frosted bubbles that were popular for several years. Since they skylight is often the high point in the room, the heated air gets up there, and if there is a sudden cool-down outside, well, you know how it works. The cheap 1960s aluminum-framed windows had similar problems with staining the sills.

-- aem sends...

Sure, if they were Velux and installed correctly it's entirely possible that skylights could be leak free for 20 years. On the other hand, if you use crap skylights and install them incorrectly, they could be leaking from day one.

Which is different from the question "Do all skylights eventually leak?" The answer to that is yes, like everything else their life is not infinite. At 20 years, they are a lot closer to the end of their life than the beginning. When you need new ones, I'd go with Velux.

My velux are 25 years old and have never leaked .

Yes, it IS possible. Can't remember the brand right off hand, but there is at least ONE that meets that requirement.

I remember now - it is VELUX. If installed according to their instructions they will NOT leak.

snipped-for-privacy@ymail.com wrote in news:cab5cc7b-90d1-412b-b5c4-b6f1f52914d4 @r22g2000vbp.googlegroups.com:

Well yes & no.

House I stayed in for a year had two fixed Velux skylights. Leaking a little after like 18 years I was told. Put new roof on and redid skylights. Actually I reused the same Velux metal flashing and trim. Put down WSU, Waterproof Shingle Underlayment typically used at eaves for ice issues, per Mike Guertin's "Roofing with Asphalt Shingles"/Taunton Press. Realigned step (side) flashing, roof cemented all old nail holes, renailed and roof cemented nail heads. No runs, no drips, no errors in the year since. Very heavy northeast snow area.

On 2/23/2009 1:13 PM snipped-for-privacy@ymail.com spake thus:

The building I live in has skylights in all units, installed at least 20 years ago. Of the two units I've lived in, none of them have leaked (each unit has 1 large fixed and 1 smaller openable skylight). My neighbor's skylight leaked during the last rainstorm, but that's the first leak I've known about in the building. So no, if properly installed and maintained, they shouldn't leak.

Yes.

Talk to me in 50 years.

A 50 year roof will leak in 100 years. Everything will leak in time and dissolve away.

Andersen stopped producing skylights around 2009. I have two in a cathedral ceiling that leaked around the rubber glass seal within the first ten years. The only thing securing the glass to the frame is friction and gravity. The frame only keeps it stationary. I've taken the glass off, put the best rubberized caulking around entire rubber gasket and five years later its leaking. With in one month April 2025, I'm having both removed.