4 Reasons Your Skylight Is Leaking and How to Repair It

If you see your skylight leaking, take immediate action. There are few things in a home that cause more damage than a persistent water leak, as they tend to spread quickly and damage almost any type of material. The first step to take is to figure out what is causing the leak. The second step is fixing it, which is usually more complicated than it first appears. There are numerous reasons your skylight might be leaking—we’ve listed some of the more common problems below.

1. Improper Installation

An improperly installed skylight is the most common reason it might leak. Flashing is a sealing method designed to direct water away from problematic spots, such as a skylight. It’s usually metal, and if installed incorrectly, it could lead to leaking. Fixing these seals is not particularly simple, so professional advice and know-how are advised. The expertise is part of the value to consider when thinking about total skylight installation costs.

2. Damaged Flashing

While improperly installed flashing can be fixed—sometimes quite simply—damaged flashing needs to be replaced entirely. Some reasons why flashing might become damaged are rusting, a bend through a bad install that worsens over time, water damage, and damage from outside factors, like a fallen tree limb or even certain unwanted, toothy guests.

3. Condensation Buildup

A faulty seal doesn’t always drip water onto the floor. If there is even a tiny amount of moisture in the window or skylight, it will fog between the panes. This somewhat depends on the type of skylight you have, so make sure you know if it’s a straight, vented, or other type of skylight before investigating. If you live in a cold climate and the weather drops, the ice that forms from the condensation can make the issue even worse, so it’s important to get this issue fixed before the colder months.

4. Damaged or Aging Sealant

The hard materials of a skylight—metal, glass, and housing—will almost always outlive the sealant. If you can catch a sealant leak early enough, it’s not a complicated fix, as you only need to recaulk the problem area. However, if any water at all has leaked into any permeable surface, such as drywall or wood, you’ll want to call a professional.

DIY vs. Hiring a Pro to Fix a Leaking Skylight

Even careful and detail-oriented DIYers should think twice before fixing their own leaking skylights. Finding a local skylight installer makes the most sense. Replacing a skylight can cost you between $1,000 and $2,750, which is much cheaper than replacing your roof or an entire wall if the light isn’t replaced perfectly. 

However, if you’re simply curious or want to discuss the project with a contractor, there are some steps you can take to investigate it yourself.

Word of caution: Anything involving a ladder or climbing on the roof brings an increased risk of injury. Unless your roof is flat, it’s probably better to hire someone. Even then, it might be the right move. 

The basic method of fixing a leaking skylight is:  

1. Find the problem: Sometimes, you just need to rip some flashing off. Best case scenario, you encounter an isolated problem area that hasn’t spread to any of the surrounding materials. 

2. Diagnose the problem: You might need a professional to help you find the problem, but if it’s something like a piece of flashing that was never properly applied or maybe just outright forgotten—it happens—you can diagnose and treat that problem yourself. 

3. If the flashing is repairable, reseal it: Take the appropriate sealant and caulk the leak. You will need a sealant that is rated for the outdoors and roof flashing, specifically. For simple leaks with no water damage, this shouldn’t take long or cost too much. 

4. Replace irreparable flashing entirely: This is a more expensive and time-consuming option than simply caulking a leak. If the housing around the flashing is damaged as well, you might need to start researching window replacement costs.

5. If there is deep water damage, you can’t find the problem, or it simply is too much work, call a local professional. 

When your skylight leaks, it’s normal to be concerned. This is not a problem to leave until it gets worse and trust us, it will definitely get worse without the proper repairs. Be careful when investigating the cause, as you might need to get on a ladder or the roof to do so. Due to the complexity of water damage and the fact that you may need work on the roof to fix a leaking skylight, for many people, it’s better to pick up the phone and call a local skylight repair company than pick up the caulking gun.