MY SKYLIGHT IS LEAKING!
Poor Roofing/ Flashing Connection
This is a very common leak that we see. I would say most Roofers are pretty good at reconnecting the skylight to the roof but often they don't change the skylight or the flashing. At minimum the ice and water shield and flashing should be fully replaced when re-doing your roofing. There are many more little nuances that are required and that's why it's best to hire a roofer and skylight expert at the same time to ensure a perfect skylight and roofing connection.
We will get a lot of phone calls after a heavy wind-driven rain storm. Most of the time the homeowners skylight is fine until we get something a little more aggressive and it will start to expose some weaknesses of the skylight system. These are issues where it takes a real skylight pro to find out really where the problem is and how we can tackle it moving forward.
An old skylight can fail in many areas. The most common area it fails is at the seal from the dome to frame or if its glass than at the Glass to frame connection. Whether it's dome or glass it will have 2 layers of domes or 2 panes of glass. Often the old domes will become brittle and crack.
Expansion and contraction is an extremely important factor when it comes to skylights and that's why sometimes by hiring someone to caulk the skylight is bad because it bonds each component of the skylight together and it can no longer expand and contract and that's what causes a lot of cracks.
For obvious reasons a cracked skylight becomes very vulnerable to leaking. Often the outer acrylic dome will crack first and that will cause a lot of rain to get trapped in between the domes which can be quite nerve-racking to look at when you have a couple of litres of water trapped in your old skylight and it looks like it will break through at any moment.
With Glass skylights, a crack is usually more like a shatter. by using tempered glass this makes it a lot safer than just regular glass because if it does break then its really difficult to get cut or hurt by this. Keep in mind this is extremely rare and has only been reported twice in the last 10 years.
Fundamentally skylights are pretty sensitive to how they are installed but more importantly what they are installed over. For example, it is very wrong to install a self-flashing skylight onto a flat roof. This is something we see all the time because a self-flashing skylight is cheap and easy to find at any home depot and a contractor just tries to wing it and throw it down. Certain skylights fasten down to certain roof types and require certain flashing! This is a very important step that we have seen go wrong all too many times.
Another example is Deck mounted Skylights need to have a minimum roof pitch. They will fail prematurely if installed onto too low of a roof pitch. This will result in leaking in the bottom corners near the glass or or thorough the roof connection.