APT International – Steel Window Restoration

APT International – Steel Window Restoration


[ Music ]>>Rolled steel section windows have been an
area that is becoming increasingly important in the preservation field in the last 20 years. The younger people coming into the field
now are going to find that they’re going to be continually charged
with dealing with them.>>The genesis of steel windows
is most pronounced in the latter part of the 19th century. They played well to the architecture that
was also growing out of the late 19th century and certainly most pronounced after World War I. The fact that the large expanses
of glass, and ribbon windows, and massive sizes of the windows, which were
intended to admit large amounts of daylighting and ventilation, it was able to be addressed
with the incorporation of steel technologies. Simply by virtue of a relatively small section of window framing elements spanning
a relatively large distance.>>I really feel that while we so often
associate rolled steel section windows with industrial buildings, that one of
the most significant aesthetic uses is with prominent residences in the 1920s, and
I think this is an area where we really need to pay greater attention, because I
think these window systems are in danger.>>Steel windows, from a residential perspective,
were popular because of the aesthetic. Kind of an industrial type of aesthetic, used more commonly during the
art deco times of the 1920s. I suspect they fell out of popularity
because of issues with frosting and issues with the performance of the
windows themselves in time.>>The problems are all going to be similar. Basically you’re going to have rusting on the bottom frame members,
rusting on the subframe members. You’ll undoubtedly have hardware problems, And the hardware problems will differ
a lot depending upon the amount that the windows have been used.>>When we evaluate any facade component,
including windows, we start at a global level, and we work down toward the micro levels. Looking at the windows as a whole, their general
condition, how they work, how they function, how they’re integrated into the wall system,
the conditions themselves are a function of looking at them in greater detail. Often times, in the evaluation of steel
windows, what we ideally like to do, actually in the evaluation of any type of window,
is to disassemble them, so that we’re able to look at the components which may be
concealed from view to determine the extent of deterioration and potentially what is necessary for a restoration. With steel windows, one of the most common
types of distress is, at a basic level, it’s deterioration of the coatings. Often what has been done and is done
is the existing coatings are overcoated with a new coating, and over time,
particularly with buildings and steel windows, which are now approaching 100 years old, they
could have multiple layers of paint on them, which begin to affect their performance. At a more systemic level, it’s deterioration
and corrosion of the steel components.>>The first thing we do is we take a look
at the windows, and take a very good look at the scope that the designer has put together, and make sure that the work is
covered, and it’s stuff we understand.>>It’s so much easier to get the full scope
of the work covered if the documentation and the original documents are, all the aspects are there. Do they have a full window schedule? Does the window schedule
have all the measurements? Does the window schedule have the scopes? Is there a types page for the window schedule? And that’s– that’s my biggest
pet peeve if I had one. [ Music ]>>The project split into two parts. Basically we have on-site work
and we also have in shop work. So the windows start from being
removed from site by our contractors, and brought over to our shop for restoration. And that’s when we actually begin the
process of blasting, painting, abatement, many different trades that
we have going on in our shop.>>Our processes here are maintaining
all the different contractors, to make sure that windows, before shipment, all the processes are corrected
prior to arriving on site. A lot of it is organizing and sequencing
what needs to be done before other things. So there’s film, and coating thicknesses. There’s blast film checking. Hardware assembly, and glazing.>>So, each bay of windows is assigned its own
numerical value for that specific bay number. It’s unique to only that bay, and then
each window is assigned a letter value within that bay. So, once we receive the window, we break
it down and separate its components. Windows typically has between
5 and 12 components, and each specific component is
tagged according to that window. Once the window’s tags and all the components
start breaking down in tags as well, we put it into a rack where that
corresponding tag matches the rack tag, and once all the components are in
there, we keep everything organized. It’s very important to keep everything in
that specific area because, once again, each window size is different,
and it’s really important that we put the specific window
right back where it belongs.>>One of the big reasons that tagging
and the whole tagging process for any kind of a steel window job is very important is because steel windows and steel components
and steel metal parts are very unforgiving. Two windows might be the
same type, the same size, — and the glazing stops might
be the same type and same size — You think they’re interchangeable, they are not. So typically, if you get a thread for a
screw hole and be off by a 64th of an inch, that screw is not going into the hole. So, typically the different parts of the window
that get broken down are the sash and the frame. Typically there are some hardware pieces
on the frame that need to be removed. All the threads on every single thing
need to be chased out with a tap, to make sure that they’re all clean.>>The first step would be abatement, which means we take all the asbestos-containing
materials and scrape that away from the window. We do that in our specific asbestos containment,
and then we pass the window on to blasting. The asbestos process is actually one of
the more simpler processes in our shop. It’s just hand tools, and they specifically just
scrape the edges of all the windows. So with the asbestos removal, all the trades
who work for that, have to have Tyvek suits, a breathing apparatus, and the
containment itself is negative air machine. We test for lead regularly, and we
have an outside firm come through and test for lead levels in the air. Once the guys bring the window into the
containment, and do their asbestos removal, once they’re completed with
that, they have to shower, and take off their suits before
exiting the containment. Once we go into blasting,
this is the lead paint removal. At that point, the window should be
contaminant free, and safe to work with.>>Removing of the existing coatings
can occur in a couple of different ways. There can be chemical strippers that are used
in order to remove the existing coatings. Chemical strippers are good
because they contain the lead, and so disposing of the lead-containing paint is
a much easier process, using chemical strippers. The downside of chemical stripping is,
it’s very difficult to remove coatings from the various crevices,
and inside surfaces that exist in any window, and doing that can be difficult. The most effective method of removing
of coatings is a blasting process. What’s important in a blasting process
is that you have a media selected that will not damage the steel
during the blasting process.>>If a paint system has a prescribed tooth
level that it needs as for the substrate, there is recommended grits that you can use, and
different blast media that you can use to get down to different levels of that tooth. So, if you needed something finer, maybe
you’d use a finer sand, for a smaller tooth. If you needed something bigger,
maybe you’re using an iron oxide, or something a little bit more gritty.>>So, our blasting professional
has his own specific containment. What we want to do in here is create a dust-free
environment to keep anything out of getting between the glass and the blasting itself. Once the window is then blasted, we
put it in the zinc priming containment. That’s when the paint process begins. You start with the zinc epoxy, and
intermediate epoxy, and then a final coat.>>The reason we use zinc
is for corrosion prevention. We coat both sides in one day, because
it’s an 8-hour flash period uncoated, so we have to make sure we do that in one day. We keep each portion of the coating process
separate, because there’s all different types of contaminants that can
definitely affect the coating.>>So, once the window is zinced,
and basically rust protected, it moves into the intermediate epoxy, which is the second separate process,
and also a separate containment. So once the windows are in this containment,
the intermediate epoxy process begins. He sprays those, we flip them in
there, and typically they can stay in there for the final coating as well.>>You want to make sure you have the proper
protective equipment doing any coating, because any solvent-based
material could be dangerous, and is dangerous to inhale
or breathe any type of vapor. So you want to make sure you
have the proper respirator. You want to make sure all your skin is covered. Hands, gloves, long-sleeved
shirt, and a spray sock. And any exposed skin some people
even like to apply a bit of Vaseline to make sure nothing is touching your skin. So, all the windows come back
with their original glass, most of which is heavily
damaged or missing completely. So we have went ahead and replaced all glass in
the project with a single-pane monolithic glass, with glass film, for solar
retention as well as safety.>>Whenever you’re dealing with old glass,
definitely just research it and make sure that what you’re providing as a replacement is a
viable option and will look correct for the building. Even if you’re in a historic building, and the
glass looks just like it’s regular float glass, or it looks like it’s, you know, something that is commercially available that’s,
you know, cheap and easy to get, It might not be, so you have to really look at the
color of the glass, the texture of the glass. Everything about that glass that
makes that building special. If you start changing portions of
that, that’s going to create a problem.>>It was really difficult to find somebody who
would be able to procure all the different sizes for this project, but there being so many,
the challenge was measuring all this glass and sending it over to somebody
and getting different quantities, and all that stuff provided
for each window type. We are able to get a single-pane
monolithic glass in the correct size and have them provide all the
glass for the entire project.>>The fresh glass is brought into the
clean room, which is then cleaned and sprayed with a solution of soap, water,
and a little bit of alcohol. The film applicator cleans and
applies water to the glass, which is then the glass film is
applied onto that, set into place, and cut to make sure that it fits each one. It’s then squeegeed out so that it applies, and then needs about a 24-hour curing
process for all the water to be removed. At that point, after 24 hours, we do a check
to see if there is any inclusions, bubbles, scratches, misplaced film, or misaligned
film, and getting that done prior to assembly was a key for this project.>>Once everything is painted, it comes back
out, and we start the reassembly process. So all of these pieces that
got disassembled, tagged, and went through the restoration
process, they’re now coming back together. Everything gets laid out on the table,
and you start piecing together the window, inserting the glass, so maybe, depending on the
setting detail, if you’re using some butyl tape, maybe in there, to hold the glass in, put
the stops back on, and then you’re doing like a caulk joint on the interior
and the exterior of the glass.>>The end goal here is obviously organization. And it’s very important to
keep everything together. Each window has its own components in the rack, as well as a glass size that’s specifically
tied to that window. So once the window is taken off the rack and put into the glazing containment,
everything is already provided for that window. So you’ll have the frame, the sash
itself, as well as all glazing components, and the glass provided with that window. Typically with the glazing process,
we receive the windows after paint, and bring them into our glazing containment. We use about a quarter-inch glazing tape,
which is put around the edges of the window, and then the glass specific to that window
size is set into the glazing pocket. On the other side, we use
metal glass glazing stops. With the glazing process, it’s really
important that we have a neat and clean edge. It’s not only for looks, but it
also helps with water distribution and keeping rust off of the windows.>>So the most important part of the quality
control is definitely the final check. Checking every window right before packaging,
going through all of our previous checks, making sure that all the corrections were made,
making sure that all the hardware is functional, assembled, and in the right spot. Also there’s a final cleaning
prior to packaging. And a lot of these processes
needed to be done inline, upstream.>>Once it’s been determined that the
window is good for on-site shipping, we then begin to wrap all the windows in foam,
tape the windows up, and make sure to put that specific window number
and bay number on the outside, and so our on-site professionals
know where exactly this window goes.>>What’s very important in the reinstallation
process is minimizing the damage that’s going to be done to the windows
that requires touch-up. Some damage is inevitable. That’s part of the process of reviewing
the windows once they’ve been reinstalled.>>So, once the window is brought over to this
site, my on-site team will organize it according to the window number, and the bay number. So they remove the window from the trailer, cart it over to that specific
bay, and unwrap the window. Once the window is unwrapped, they can
begin to start the installation process. They attach the frame to a
hoist system, and bring it up to that specific opening, put the window in place. Before they put it in place, they want to caulk the interior pocket to
create another weather seal. The window is then pushed into this glaze, and
all mechanical components are then fastened into place, for brick molds,
and any of the original pieces that were holding this window in place as well.>>So, in terms of maintaining a
window once it has been restored, certainly looking at the window, at a cursory
level, on a regular basis every few months, every year, certainly at the
most, in terms of understanding if it’s functioning properly,
if there are issues with it. In terms of post-occupancy evaluation of
restored windows, or dealing with clients after steel windows have been restored,
there’s a need to manage expectations so that they understand that even a restored
steel window is not going to perform as well as a new modern window in terms of being
potentially drafty, having cold surfaces on it, and even condensation forming on
the glass, and the frame itself.>>The greatest lesson learned in ongoing
restoration of historic steel windows, these are durable elements that people readily
fall in love with, that will perform many, many, many years, decades, even generations into
the future, and that’s why we’re here. That’s what we live for. [ Music ]

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