You notice a stain around your skylight.  Unless your skylight is in a sauna or over the shower and condensation is a constant problem your skylight is probably leaking.  This article addresses the most common reasons skylights leak and about replacement skylights Fairfax VA. 

Skylights generally leak in one or more of 4 places

1.  Least common but certainly possible is that the roof upslope or adjacent to the skylight has a leak and water is running over the underlayment or plywood until it finds the skylight opening and enters your home.  These leaks can be as easy to fix as a nail popped through a shingle or a vent pipe flashing needs replacement or as big as the roof itself is just plain worn out and needs to be replaced.

2.  The skylight glass/dome has a crack or hole:  This is more common with the older acrylic dome skylights.  After decades under the sun these acrylic domes become brittle and start to crack.  Water gets in through these cracks and enters your living space.  This is fairly easy to identify through an exam of the skylight.  

Cracked skylight Replacement Skylights Fairfax VA

3.  The skylight flashing is leaking.

Bad Installation

Most modern residential skylights come with a flashing kit made by the manufacturer.  These rarely fail though they can be installed incorrectly.  Look for loose exposed and rusty nails along the bottom apron flashing.  Gently prying up shingles along the sides where they meet the skylight look for nails that were nailed too low along the step flashing or back pan.  If these nails are rusty it means water is running over them with a good chance of being a leak.

Wrong Materials

The most common skylight flashing leak is when the roofer or skylight installer makes his own flashing from aluminum.  Factory flashing kits cost about $100 each while the metal to make flashing at the job about $10.  Since cheap aluminum cannot be soldiered or welded the roofer uses caulk at the corners to keep water out.  In 5 to 10 years caulking dries and shrinks.  Water starts to leak in.  By the time a stain becomes noticeable on the ceiling water may have been coming in for months or years and possibly surrounding roof wood is compromised as well.

Signs of a Failing Skylight


This type of leak is characterized by stains lower down or at the bottom of the skylight well, typically on the upslope side of the skylight.

It’s possible to solve these leaks by removing and replacing the old loose caulk.  This is temporary at best but if one is selling the property or expects to replace the roof and skylights soon, this is an economical solution.  IF one has a deck mounted skylight in most cases it’s better to replace the flashing with a factory-made kit and also the skylight. 

The seal between the glass and the skylight frame is leaking 

These leaks are characteristically high up near the glass on the downslope sides of the skylight.  If one’s skylight is a deck mounted model the sides of the skylight frame can be stained/discolored.  If you are checking the skylight from the roof look for dark spots under the glass at the corners, especially the bottom corners.

Like caulking, the sealant between the glass and the skylight frame eventually dries out, shrinks and cracks.  Water oozes in slowly at first but these leaks don’t get better on their own.

Will a Temporary Fix Work? Can I Repair the Skylight?

A temporary fix is to clean and seal the glass to the surrounding frame.  Generally, these fixes start to leak again within 6 months.  The main problem with this type of fix is that the leak will be slow at first and just dampen the interior without showing through.  This is a recipe for mold, rotten wood, bugs and a much larger expense down the road.  Much better to replace the skylight and flashings with new. 

When Do You Need to Replace the Skylight?

The reason for this being the skylight is probably at the end of it’s useful life and will need to be replaced soon anyway.  Most of the labor is already being paid for by replacing the flashing and really one is just paying the material cost for a new skylight.  It’s quite possible too if a skylight is near the end of it’s life the disturbance of having the surrounding flashing removed will be the straw on the camel’s back and the seal between the metal frame and glass with fail, then or soon after.

Replacement Skylights Fairfax VA

Before selecting a roofing or skylight contractor in Fairfax, call and ask about your project and for a free consultation.

When you pick a certified, licensed roofing and skylight contractor, you will save in the long-run by avoiding problems caused by improper installation.

Call to learn more about our process for replacement skylights Fairfax VA and to see our work, give us a call at 703-721-4420 to speak to one of our professionals.