Skylight repair and installation in Horsham and nearby

Is it a leak, or is it condensation?

Before you call anyone, figure out which one you have. It changes the fix completely.

• Drips only when it rains, or when snow is melting: that is a leak. Water is getting past the roof around the skylight.
• Water on the inside of the glass on cold mornings, even in dry weather: that is condensation. Warm, damp air from the house hits the cold glass and turns to water. Very common over bathrooms and kitchens in winter. The cure is running the bath fan and lowering indoor humidity, not a roofer.
• Fog or haze between the two panes that will not wipe off: the seal in the glass unit has failed. Not a roof leak, but the skylight is near the end of its life.
• Stains on the drywall of the light shaft below the skylight, especially at the top corners: almost always a leak at the flashing.

A simple test: On a dry, cold morning, wipe the glass and the frame completely dry and tape a paper towel to the bottom of the frame. If it is wet by the afternoon with no rain, you are dealing with condensation.

Why skylights leak: usually the flashing, not the glass

A skylight is a hole in the roof. What keeps water out is the flashing: the metal pieces that run around the frame and weave in with the shingles so water is steered around the opening. When a skylight leaks, it is almost always one of these:

• Caulk instead of flashing. Someone sealed the frame with caulk or roof cement instead of proper flashing. It works for a few years, then cracks.
• Flashing layered the wrong way. Each piece has to tuck under the shingle above it and over the one below. Get the order wrong and water runs straight in.
• Debris and water piling up on the uphill side. Leaves and snow collect above the skylight, and water backs up under the top flashing.
• The skylight was reused on a new roof. Old flashing on a new roof rarely seals well. If you are getting a roof replacement, replace or at least reflash the skylights at the same time.
• The unit itself has failed. Cracked frame, broken seals, or warped plastic on an old dome-style skylight.

The good news: if the glass is clear and the frame is sound, reflashing usually stops the leak without buying a new skylight. We take the shingles off around the frame, put in new flashing properly, and shingle back. If the leak turns out to be somewhere else on the roof, which happens, see roof repair.

Repair or replace the skylight?

Repair it when

• The glass is clear, with no fog between the panes
• The frame is not cracked or warped
• The leak is coming from around the skylight, not through it
• You are not planning a new roof in the next couple of years

Replace it when

• The glass has fogged between the panes, or an old plastic dome has gone cloudy or cracked
• The leak came back after it was already reflashed
• You are replacing the roof anyway; it is the cheapest time to do it
• You want a venting skylight where you now have a fixed one

Either way, we look at the unit and the flashing separately and show you photos, so you can see why we are recommending one or the other.

Adding a skylight or a sun tunnel

• Fixed skylight. Does not open. The simplest and least expensive way to bring daylight into a room with an attic or vaulted ceiling above it.
• Venting skylight. Opens, by hand or with a motor, to let heat and steam out. Good over kitchens, bathrooms and upstairs rooms that get hot.
• Tubular skylight (sun tunnel). A small dome on the roof and a reflective tube down to a round lens in the ceiling. Fits where a full skylight will not, like a hallway, closet or windowless bathroom, and makes a much smaller hole in the roof.

A new skylight means cutting the roof deck, framing the opening, and building a shaft through the attic to the ceiling below. The flashing work is the same roofing work as a repair, done right the first time. If your shingles are near the end of their life, the roof inspection will tell you, and adding the skylight during the re-roof saves money.

What it usually costs

A reflash on one skylight is at the low end of repair. A new skylight costs more when the opening has to be cut and framed and a shaft built through the attic, and less when it goes in during a roof replacement.

• Skylight Repair: $350 – $1,800
• Skylight Replacement: $2,200 – $5,500
• Skylight Installation: $1,800 – $4,500
• Fixed Skylight Installation: $1,600 – $4,000
• Venting Skylight Installation: $2,500 – $6,500
• Tubular (Sun Tunnel) Installation: $1,200 – $3,000

Questions we get asked

Why is my skylight leaking?

Usually because of the flashing around the frame, not the glass. Caulk used instead of flashing, flashing layered in the wrong order, or debris piling up on the uphill side are the common causes. If the glass is clear and the frame is sound, reflashing usually fixes it.

Is water on my skylight a leak or condensation?

If it drips only when it rains or snow is melting, it is a leak. If the inside of the glass gets wet on cold, dry mornings, it is condensation from humid indoor air, and better ventilation is the fix. Fog between the panes means the glass seal has failed.

How much does skylight repair cost?

Skylight repairs we do typically run $350 to $1,800, with reflashing a single skylight toward the lower end. A full skylight replacement typically runs $2,200 to $5,500. You get a written estimate before any work starts.

How much does a new skylight cost?

A new skylight typically runs $1,800 to $4,500 installed. Fixed skylights are usually $1,600 to $4,000, venting skylights $2,500 to $6,500, and tubular sun tunnels $1,200 to $3,000. Adding one during a roof replacement costs less.

Should I replace my skylights when I get a new roof?

Usually yes, or at least reflash them. Old flashing rarely seals well against new shingles, and the roof is already open, so it is the cheapest time to do it. If the skylights are newer and the glass is clear, new flashing alone may be enough.

Can you put a skylight in a hallway or bathroom with no attic space?

Often a tubular skylight works there. It needs only a small hole in the roof and a tube down to a lens in the ceiling, so it fits where a full skylight will not. We look at the attic and roof framing first to confirm it will work.

Related pages

• Roof Repair: Leaks, missing shingles, flashing and vents. We fix the problem and tell you honestly how much life the roof has left.
• Roof Replacement: Full tear-off and new roof when repairs stop making sense. Written, line-item estimate before anything starts.
• Roof Inspection: A free, top-to-bottom look at your roof with photos, so you know what you actually need before you spend anything.
• Shingle Roofing: Architectural asphalt shingle repair and installation, the roof on most homes around here.
• Flat Roofing: Low-slope roofs over porches, additions and row homes, where ponding water is the enemy.
• Emergency Roof Repair: Active leak or storm damage? Call any time, day or night. We tarp it to stop the water, then make the permanent fix.
• Horsham: Home base. Our shop is here.
• Blue Bell: Larger homes with complex rooflines and lots of valleys.
• Dresher: Colonials and split-levels across Upper Dublin.
• Maple Glen: Established neighborhoods minutes from our shop.
• Doylestown: Historic borough homes plus the townships around it.
• Montgomery County: Where we do most of our work, from Horsham out across the county.