The old galvanized steel pyramids, hips and ridges over New York's schools, factories, lofts, warehouses and stair bulkheads are nearly all glazed with wire glass, and most of them are somewhere between eighty and a hundred and twenty years old. They are still up there because nobody has had to take one down yet. They leak, they sweat, they drop their putty, and the glass in them is not what most owners think it is. This is work we do, and this page is what we would tell you standing on the roof.
Four things, in about this order, and the one that matters most is the one you cannot see from the ground.
| What is happening | Why it matters | |
|---|---|---|
| The frame rusts from the inside out | Water gets into the steel section and stays there. The member corrodes from the inside face outward. | The outside can look weathered but sound while the steel behind the paint has lost most of its thickness. This is why a frame that looks reglazable often is not. |
| The glazing putty hardens and drops out | Putty is a maintenance item, and on most of these it has not been maintained in sixty years. It goes hard, cracks and releases the pane. | Once the pane is loose, water reaches the rabbet and the corrosion accelerates from there. Panes also start to slip. |
| Single glazing means condensation | One layer of glass in a steel frame with no thermal break is a cold plate in January. | Warm inside air condenses on it and runs down the frame. Owners chase it as a roof leak for years before working out it is not coming from outside. |
| The curb underneath is usually the real story | On a roof this old the curb has been reroofed around several times. Membrane run up, cut, patched, run up again. | Replacing the glass over a failed curb solves nothing and it leaks again by spring. We look at the curb and the flashing before anyone talks about a unit. |
This is worth being plain about, because once owners understand it they usually decide differently. The steel mesh in wire glass is there to hold the broken pieces roughly in place. That is its whole job, and it is why the material was used where the spread of fire was the concern.
It does not make the pane stronger. Wire glass breaks at a lower impact than plain glass of the same thickness, because the wire interrupts the glass, and when it goes it leaves shards hanging off the mesh instead of falling clear. Under a stair, over a school corridor, or above a floor where people work, that is a different proposition from the tempered and laminated glass that goes into a modern unit.
What your particular building is required to carry is a question for your architect or expediter and the department, not for us to answer on a web page. We are happy to be in the room for it, and we have written up what the city looks at on our permits and landmark rules page.
On most of these it is a thermally broken aluminum pyramid, hip or ridge on a rebuilt curb, with the geometry matched to the existing opening so the roof and the ceiling below are not reworked more than they have to be.
We measure the opening, look at the condition of the steel and the curb, and work out how a unit that size gets to the roof and into place. Nothing gets quoted off a photograph.
Repaired or rebuilt as found, with the membrane and the flashing tied back in properly. This is the part that decides whether it leaks in five years.
Finish and profile chosen with the building in mind, which matters when the unit is visible from the street or sits in a historic district.
Tempered on the outboard lite, laminated on the inboard lite, with a low-E coating where the space needs the heat control.
Written, and it says what comes off, what goes back on, and what the roof looks like when we leave. Product data included.
Certificate naming the building, the managing agent and the board as additional insureds, plus our license number, before the crew arrives.
Public and private schools, factory and warehouse buildings, loft conversions, stair and elevator bulkheads, churches and synagogues, industrial daylighting over shop floors, and the top floor of a great many older co-ops. If a building put daylight into a large space before the war, there is a fair chance there is a galvanized frame with wire glass over it, and a fair chance nobody has been up to look at it in a decade.
We do the ordinary residential work too. If what you have turns out to be a standard replacement rather than one of these, our labor and unit pricing is published on the pricing page. Commercial and general contractor work, including how we handle submittals and lead times, is on the commercial page. If it is leaking right now, start with skylight leak repair.
Honestly, not from a table, and we would rather say that than publish a range we would not stand behind. No two of these skylights are the same size and almost none of them match anything a manufacturer keeps in stock, so the frame and the glass are fabricated for the opening. A real number comes after somebody stands on the roof.
What we can tell you before the visit is what drives it: the size of the opening, the geometry, because a flat ridge is not a six sided pyramid; the condition of the curb and the steel; whether the glass can be carried or has to be craned; how much of the work has to happen outside normal hours; and whether the building is landmarked. The assessment is free and it is the fastest way to find out what you are actually dealing with.
Brooklyn · Queens · Manhattan · The Bronx · Staten Island · Long Island · Westchester. Licensed and insured, LIC# 2084179. Skylights are all we do, and we have been doing them in New York since 2005.
Wire glass is a single pane of glass with a steel mesh rolled into it while the glass is still hot. It was the standard glazing on steel framed skylights, stair bulkheads and factory sashes for most of the twentieth century, so almost every old galvanized pyramid, hip and ridge skylight still in service in New York is glazed with it. It is a single layer with no insulating value and no coating.
No, and this is the most common misunderstanding we run into. The mesh is there to hold the pieces roughly in place if the pane breaks, which is why it was used where fire spread was the concern. It does not make the pane stronger. Wire glass is weaker in impact than plain annealed glass of the same thickness, and when it does break it leaves shards hanging off the wire. Modern replacements use tempered and laminated glass, which is a completely different thing.
Sometimes, and we will tell you when that is the honest answer. If the steel is sound and it is really the putty and the glazing that have failed, reglazing is a smaller job than replacement. What usually decides it is corrosion. These frames rust from the inside of the section outward, so the paint can look tired while the steel behind it is already gone. We look at that before anyone quotes a full unit.
Because a single pane of glass in a steel frame is a cold surface with nothing to break the heat path. Warm indoor air hits it and condenses, then runs down the frame and onto whatever is under it. People report it as a leak for years. A thermally broken frame with an insulated glass unit is what stops it, and it is one of the bigger day to day improvements owners notice.
On most of these we set a thermally broken aluminum pyramid, hip or ridge on a rebuilt curb, glazed with an insulated unit that is tempered on the outboard lite and laminated on the inboard lite. The geometry is matched to what was there so the roof and the interior opening do not have to be reworked. Where the unit is visible from the street in a historic district, the profile and finish are part of the conversation before anything is ordered.
Not off a table, and we will not pretend otherwise. No two of these skylights are the same size and almost none of them are standard, so the glass and the frame are fabricated for the opening. Pricing comes after a site visit where we measure the opening, look at the condition of the curb and the steel, and work out how the unit gets to the roof. Standard residential replacement pricing is published on our pricing page. This is not that.
Schools, factory and warehouse buildings, loft conversions, stair and elevator bulkheads, churches, and the top floor of plenty of older co-ops. Anywhere a building put daylight into a big space before the war, there is a good chance there is a galvanized frame with wire glass over it.
Yes, and on schools and occupied buildings that is normally the requirement. The work happens from the roof side, the area below is kept clear while the old glazing is out, and the opening is closed each day. Sequencing, roof access and who needs to be notified are worked out before the crew shows up, not on the morning of.
We ask that before anything is cut. Opening a roof that is still under an active manufacturer warranty can void it, and on a commercial roof that is a real number. If there is an active warranty we find out what the manufacturer requires and work to it.