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Posted on Fri, Sep 16, 2011 : 7 a.m.

Identifying the cause is key when repairing a leaking skylight

By Keith A. Paul


photo by: Kevin Gillespie

Hi Keith,

I have a skylight leak that started this year which two contractors have already repaired and the leak continues. I’d like to do the repair myself to trust that it is done correctly. I’ve already replaced one roof,. the skylight is only five years old and appears to be in good shape. Can you offer any suggestions to help me stop throwing money out the window?…literally.

—Bart S., Ann Arbor

Hi Bart,
You are one of many when it comes to having a skylight with a leak. Unfortunately, the common failure is due two main factors, improper installation and deterioration in the window seal or flashing.

Identifying the cause of the issue is a necessity. You must re-create the leak. Either carefully watch the area when it rains or use your garden hose and run water over the skylight and recreate the leak. If you notice water where the glass meets the window, the seal is broken, and you either need to reseal the glass or have the entire skylight replaced. This is usually best completed by a professional.

Because the skylight is only five years old and it just started leaking, we’ll cover how to repair the leak by correcting the most common cause… for good — the flashing.

I’m glad to hear you have minor experience on how shingles are installed on a roof. It will help you with your first step. Carefully remove the shingles approximately 12-18 inches around the perimeter of the skylight using a pry bar.

Start above the skylight and work your way down around the sides, then bottom. Be careful not to damage any remaining shingles, as it could trigger another leak and cause me to write another roof repair article for next week's column.

Next, remove any roofing paper down to expose the existing plywood. Be sure to leave the paper only around outside the remaining shingles which will soon be covered. Then remove all debris such as existing caulk, shingles and dirt in order to have a clean work area.

Next, use a sticky back roof paper, (also known as tar paper), and cover the exposed roof and skylight flange. Before applying the shingles, install aluminum flashing around the perimeter of the skylight and caulk in place. This will give you extra protection in case the existing flashing is damaged or starts to deteriorate.

As always, when installing the new shingles, keep safety in mind. I’ve been involved in too many roofing slip and falls and do not want to add any of our readers to the list! Enjoy your new leak-free window.

Paul is a State of Michigan Licensed Builder. Paul serves as President and founding member of Nationally franchised HandyPro Handyman Service, servicing Washtenaw, Wayne and Oakland Counties. Listen to Paul every Saturday at 11 a.m. on “It’s Your Business, Make It Happen” WAAM Talk 1600AM. Email questions or comments to


Craig Lounsbury

Sat, Sep 17, 2011 : 9:17 p.m.

If its a Velux, and its leaking in either lower corner its probably failed glazing. If so you an fix it for a 5 buck tube of silicon and redo it every 5 years or you can pay Velux for a glazing replacement kit. The last thing I'd do is pull the shingles preemptively. I would Cover the upper part of the skylight above the roof line with some sort of plastic sheeting , duct tape and wait for several rains. If the leak stops its a glazing issue. If the leak continues its either a roof flashing issue or possible a leak that originates somewhere else and exhibits at the skylight. I have fixed a couple "skylight leaks" in my day by replacing the flashing boot on a plumbing stack 4 feet above the skylight. with respect to mgnfcntb's ice and water shield comment, realistically if water ever hits the ice and water shield it has penetrated the system and will migrate downhill and show up somewhere else. Unless the Ice and water shield goes all the way to the eve.


Fri, Sep 16, 2011 : 12:33 p.m.

I'm sorry but if you have not encased the box in ice and water shield you have voided the warranty (velux?). Skylights are tough and should not be dealt with caulk or little experience. Good luck