Skylights allow sunlight to filter into your home, but they can crack. When this happens, you have to assess the true damage before you make a decision. A crack that causes the skylight to leak can cause great damage to your home, and you need to take action. Not all cracks leak, though.
Replacing the Skylight
When the crack is serious, you need to replace the skylight. Arizona Roofer suggests that it's easy to do this if you have a curb-mounted skylight, but you should call a professional for a self-flashing skylight. Go to the roof and measure the size of the skylight and purchase an exact match. Remove the cracked skylight by taking out the screws along the bottom edge, lifting it directly up and replacing it with a new one.
If you'd rather have a professional handle the replacement, you might still need to cover the skylight temporarily as you wait for your appointment, particularly if the weather report suggests rain. Cover the skylight from the outside with a large tarp, securing the edges with tape to prevent water from leaking inside.
Patching the Crack
If the crack is small, you don't need to go through the expense of replacing the whole skylight. Instead, you simply can repair the crack. To do this, apply a layer of clear caulk over the crack.There are also products on the market meant specifically for skylights that do the same thing. Note, though, that this solution isn't always pretty.
Letting It Sit
Skylights typically have two layers, and if the crack is through only one layer and the skylight is not leaking, you do not have to do anything to fix it. You can leave it alone. When doing this, though, it's important to keep an eye on the skylight, to see if the crack gets larger or starts leaking. At that point, you'll need to consider repair or replacement.