Windows
99 Years in the Same Window
Restoring One of House 173's Original Double-Hung Windows
I've Never Done One of These Before
After nearly three decades of working on House 173, you'd think I'd be running out of firsts.Nope.
This time I'm tackling something I've somehow managed to avoid since we bought the house in 1997: completely dismantling and restoring one of 173's old double-hung sash windows.
And when I say completely dismantling, I mean completely dismantling.
Both sashes out. Stops removed. Parting beads removed. Sash cords disconnected. Hardware removed. Old glazing removed. Paint scraped off.
Basically, I've taken a perfectly recognizable window and converted it into approximately 47 individual pieces scattered around my workshop and the study.
What could possibly go wrong?
There's a Good Chance This Window Is 99 Years Old
House 173 was built in 1927, which makes her 99 years old this year.And from everything I can see, these double-hung windows appear to be original to the house.
I can't prove that somebody didn't replace them in 1934 or something, but the construction, hardware, woodwork, and layers of finish certainly aren't giving me any reason to think they're replacements.
More interestingly, while stripping the exterior surfaces of the sash, I found something that connects pretty nicely with what we know about the history of 173.
Green.
And only green.
Beneath the later weathering and deterioration, the only actual paint color I've encountered on these sash frames is an old green.
Green.
And only green.
Beneath the later weathering and deterioration, the only actual paint color I've encountered on these sash frames is an old green.
That's significant because it's consistent with what members of the Mosher family, the original family of House 173, have told us about the house. For many years before we bought it, green was part of the exterior color scheme.
I always enjoy finding little bits of physical evidence like this.
It's one thing to hear somebody tell you what a house looked like decades ago.
It's another thing to scrape through ninety-nine years of paint and have the house say, Yep. They remembered correctly.
These Windows Are Worth Saving
Obviously, replacing old windows would be easier.Well...
Maybe.
We've replaced windows elsewhere at 173 over the years when circumstances called for it. Back in 1998, for example, we replaced the deteriorated basement windows, which themselves appeared to have been original to the house. You know, these old things:
But we've always tried to preserve original parts of 173 when it makes sense.
And these windows are different.
The interior woodwork at 173 is one of the things we love most about the house. The window casings, jambs, baseboards and other trim have survived nearly a century, and much of it still retains its old finish.
I don't want to lose that. So I'm approaching this restoration with one overriding rule:
Don't screw up the woodwork.
That sounds simple enough until you realize that virtually everything you're trying to remove has been nailed, painted, wedged, screwed or otherwise attached to something else for somewhere approaching a century.
How an Old Double-Hung Window Actually Works
One of the interesting things about taking one of these apart is realizing just how elegantly simple the old design is.
There are two wooden sashes, the lower sash and upper sash, each holding one large pane of glass.
The sashes ride in channels created by the stops and parting beads. Sash cords run from the sides of the windows, over pulleys hidden near the top of the jamb, and down inside pockets in the wall where they're attached to cast-iron counterweights.
Somewhere along the way I'll have to open the sash-weight access pockets and take a look at the cords, weights and pulleys themselves. Since I've already gone this far, it wouldn't make much sense to restore everything we can see while ignoring the 99-year-old machinery hiding inside the wall.
Those weights approximately balance the sash. You raise the window and the weights go down. Lower the window and the weights go up.
No electronics.
No springs.
No plastic tracks.
No proprietary replacement parts.
Just wood, rope, pulleys, iron and gravity.
And after 99 years, the basic system still works.
That's pretty impressive.
First, Take Everything Apart
Restoring an old double-hung window generally means removing the stops, carefully freeing the lower sash, disconnecting its sash cords, removing the parting beads, then doing the same thing with the upper sash.Simple.
That's what the articles and videos say anyway. They apparently weren't working on my window. Some pieces came apart reasonably well. Others seemed to have made a blood oath in 1927 never to leave the house.
And because I want to preserve the original wood and finish wherever possible, I couldn't simply pry everything apart like a gorilla.
So this became a slow process.
Very slow.
As everything came apart, I labeled it.
And I mean everything.
Left.
Right.
Upper.
Lower.
Inside.
Outside.
Wherever I thought there was even the slightest possibility that Future George might stand in the workshop holding a piece of wood and say, Where the hell did this come from?, Present George wrote something on it.
I've met Future George... and He needs all the help he can get.
More Window Work at 173
∙ Replacing the Old Kitchen Windows - 2019
∙ Repairing the Window Screens - 2024
∙ Window Work - What Was I Thinking - 2018
∙ Back Porch Rehab - 2024
⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯
A little bonus: Repurposing an Old Basement Window
Then Came the Glazing
Once both sashes were safely out of the opening, I could begin removing the old glazing.
I've done this before on old windows from 173. Years ago, I saved several of the original basement windows after we replaced them, and one eventually ended up in the shed. I later restored that window using my heat gun to remove the old glazing before sanding, priming and reglazing it.
I've done this before on old windows from 173. Years ago, I saved several of the original basement windows after we replaced them, and one eventually ended up in the shed. I later restored that window using my heat gun to remove the old glazing before sanding, priming and reglazing it.
So I wasn't completely unfamiliar with the process. This window, however, apparently took that as a challenge.
The glazing was in terrible condition.
Some of it was cracked and falling away. Some practically surrendered. And some had apparently transformed itself during the last century into a substance possessing approximately the same hardness as concrete.
The problem was that each sash contains one large pane of glass, and that made me extremely cautious.
Breaking one little pane in a six-light window would be annoying. Breaking this pane would mean replacing basically the entire window's glass.
So I took my time.
And then I took some more time.
Dental Picks. Because Apparently We're Doing Surgery Now.
For the really stubborn glazing, I brought out the heat gun.Very carefully.
Too much concentrated heat against old glass can crack it, so I worked slowly, warming small sections just enough to soften the glazing without overheating the pane.
That helped.
But even then, there were stubborn little pieces wedged down between the glass and the wood. Eventually I found myself using steel dental picks to carefully tease those bits out.
I intentionally left the existing glazier's points in place while I worked.
Those little metal points are what mechanically secure the glass to the sash, and with the glazing removed I wanted the panes to remain as stable as possible while I scraped and cleaned around them.
The goal throughout this process has been pretty simple:
Preserve the sash.
Preserve the glass.
Preserve my sanity.
So far we're three for three.
Mostly.
Down to 1927
Once the glazing was finally out, I began scraping and sanding away the old paint. This was the part I had really been looking forward to.Underneath that cracked old green paint was wood that probably hadn't seen daylight since Calvin Coolidge was president.
Somebody stood at a bench nearly a century ago and fitted these pieces together without the slightest idea that some guy in 2026 would be standing in his basement with dental picks trying to save their work.
And there it was.
And there it was.
I kept scraping. Then sanding. Then scraping some more. And eventually both sash frames were stripped down to bare wood.
Ninety-nine-year-old wood.
Ninety-nine-year-old wood.
There's something incredibly satisfying about reaching that point.
The glazing is gone. The failing paint is gone. The dirt and accumulated crud are gone.
And what's left is the actual material somebody shaped and assembled when House 173 was being built.
I know it's just a window. But I think that's pretty damn cool.
The glazing is gone. The failing paint is gone. The dirt and accumulated crud are gone.
And what's left is the actual material somebody shaped and assembled when House 173 was being built.
I know it's just a window. But I think that's pretty damn cool.
Repairing What 99 Years Left Behind
Of course, ninety-nine years haven't passed without leaving a few scars.
The lower sash had some looseness that needed attention, so I reinforced the weakened joint with a dowel. There were also damaged and deteriorated areas that needed wood filler before the sash could eventually be primed, reglazed and painted.
I'm trying to strike a balance here. I don't want these windows to look brand new.
They're not.
I want them to look like well-cared-for 99-year-old windows.
There's a difference.
The lower sash had some looseness that needed attention, so I reinforced the weakened joint with a dowel. There were also damaged and deteriorated areas that needed wood filler before the sash could eventually be primed, reglazed and painted.
I'm trying to strike a balance here. I don't want these windows to look brand new.
They're not.
I want them to look like well-cared-for 99-year-old windows.
There's a difference.
Little marks, slight imperfections and evidence of age don't bother me. They're part of the window's history. Rot, loose joints and missing wood, however, don't get grandfathered in just because they're old.
Those get fixed.
But scratches, little dents and evidence that somebody has been opening and closing this thing since Calvin Coolidge was in the White House? I'm not particularly interested in sanding all of that history away. There's restoration and then there's making something old pretend to be new. I'm shooting for the former. If this project works the way I hope, the window should look cared for, not like it came out of a box last Tuesday.
Next Up: The Window Frame
With both sash frames stripped and the glass safely intact, I've started turning my attention back to the opening itself.
I'm calling it the window frame, although I'm not entirely certain that's technically what this particular part is called.
The same philosophy applies here.
I'm scraping away the failing paint and loose material while trying to preserve as much of the original wood and finish as possible.
That's going to take some time.
There are almost a century's worth of little corners, channels and crevices in there, and old windows apparently have an unlimited supply of places where paint can hide.
But that's where I'm wrapping up this first part of the project.
Two sashes removed.
Old glazing finally gone.
Glass intact.
Paint stripped.
Repairs underway.
And some pretty beautiful 99-year-old wood seeing daylight again.
Ninety-Nine Years and Counting
I've worked on plenty of windows around 173 over the years.We've replaced some.
Repaired some.
I've even repurposed old basement windows into other projects because apparently I'm incapable of throwing away anything that might someday become useful.
But this one feels different.
This is the first time I've completely dismantled and begun restoring one of the original double-hung sash windows in the house.
And there's something satisfying about knowing that instead of pulling it out and replacing it, we're giving it another chance.
Someone built this window around 1927.
The Mosher family opened and closed it for decades.
We've looked through it since 1997.
Now, for the first time in who knows how many years, its sashes are sitting naked on my workbench with their original wood exposed again.
There's still plenty to do.
The opening needs to be cleaned and repaired. The sash needs final preparation. Everything needs to be primed. The glass needs to be reglazed. The exterior needs paint. The sash cords and hardware need attention. And eventually I have to take all those carefully labeled pieces and somehow turn them back into a functioning window.
Fortunately, I labeled everything.
Unfortunately, I'm the person who has to decipher the labels.
We'll see how that goes.
For now, though, the glass isn't broken, the woodwork isn't destroyed, and I haven't made anything appreciably worse than it was when I started.
Here at House 173, I believe that qualifies as an extremely successful first installment.
Hey, thanks for stopping by - see ya' next time!
Okay, I saw “99-year-old window” and immediately got nervous.
Because I've read enough old-house blogs to know how this usually goes. Somebody pulls out a perfectly repairable wood window, throws it in a dumpster and proudly shows us the new vinyl replacement.
Not today.
This lunatic took the entire thing apart.
And I mean apart. Sashes, stops, parting beads, cords, glazing... the whole works. Then he started picking 99-year-old glazing out with dental tools because apparently that's a reasonable way for a grown man to spend his free time.
I approve.
The best part, though, is that he's not trying to make it look new. Fix the loose joint. Replace what's rotten. Reglaze it. Get the sash working properly. But leave enough of those little dents and scars that it still looks like a window that's been part of the house since 1927.
That's restoration.
Also, labeling every part was smart.
Taking approximately 47 pieces of a 99-year-old window apart and trusting yourself to remember where they go six weeks later?
That's how Part 2 becomes a drinking story. - An Old-House Guy Who Came Here Prepared to Yell About Replacement Windows
FAQs
Are 100-year-old double-hung windows worth restoring?
Often, yes, especially when the original sash and frame are still structurally sound. Traditional wood windows were built from old-growth or otherwise high-quality lumber and were designed so that individual components could be repaired or replaced rather than requiring the entire window to be discarded. Loose joints can be reinforced, damaged wood can often be repaired, sash cords can be replaced, and deteriorated glazing can be renewed.
The real question isn't simply how old the window is, but how much of it remains serviceable. Extensive rot, badly damaged joinery or major previous alterations can make restoration considerably more difficult. Energy efficiency also needs to be considered, although restored sash windows combined with properly fitted storm windows and weatherstripping can perform much better than many people assume.
At House 173, these windows have apparently survived nearly a century. Preserving them isn't just about keeping something old, it's about determining whether a repairable part of the house can continue doing the job it was built to do.
How does an old double-hung sash window work?
A traditional double-hung window is a surprisingly clever mechanical system. It contains two movable wooden frames, or sashes, with one positioned above the other. Each sash is connected by sash cords that pass over pulleys near the top of the window jamb and attach to heavy counterweights concealed inside pockets in the wall.
As the sash is raised, its counterweights descend. When the sash is lowered, the weights rise. Properly sized weights counterbalance much of the sash's weight, allowing a fairly heavy wood-and-glass window to move smoothly and remain in position when opened.
The interior stops keep the lower sash in its track, while the parting beads separate the upper and lower sash channels. It's a remarkably serviceable design: cords, pulleys, weights, stops, beads, glazing and even damaged sections of sash can often be repaired individually without replacing the entire window.
How do you remove old glazing putty without breaking the glass?
Very carefully, and patience matters more than speed. Decades-old glazing putty can become extremely hard and brittle, and forcing a glazing tool against it can transfer pressure directly to the glass. This is especially important when working around original glass, which may already have survived many decades of seasonal expansion, contraction and movement.
Loose glazing should be removed first, gradually working toward the more stubborn material rather than trying to pry out large sections at once. Appropriate hand tools can be used to carefully separate the putty from the sash and glass. Controlled heat may also help soften particularly stubborn glazing, but excessive or concentrated heat can crack old glass and can create additional hazards when historic paint is present.
The goal isn't to remove the glazing as quickly as possible. It's to remove it without damaging the glass, the narrow wooden glazing rabbets or the surrounding sash. On a historic window, saving an extra hour isn't much of a victory if it costs you a piece of original glass or damages wood that has survived for a century.
Should old glass be replaced during a window restoration?
Not automatically. If historic glass is intact, securely seated and still usable, there can be good reasons to preserve it. Older window glass often contains slight waves, ripples, bubbles or other irregularities that subtly distort reflections and views. Those imperfections are part of what gives an old house its visual character.
Replacing every pane with perfectly uniform modern glass can noticeably change the appearance of a historic window, particularly when several original windows remain nearby. Keeping serviceable old glass also preserves another original component of the building rather than replacing something simply because it isn't new.
There are situations where replacement makes sense, broken panes, significant cracks, unsafe conditions or glass that can no longer be securely glazed. But during restoration, replacement doesn't have to be the default. At House 173, the objective is to preserve as much original material as reasonably possible while still returning the window to reliable working condition.
Should every imperfection be removed from an old wooden window?
No. There's an important difference between repairing deterioration and erasing age.
Rot, failed joints, loose glazing, deteriorated sash cords, unstable wood and other problems that affect the window's strength or operation should be addressed. Small dents, old tool marks, minor staining, slight irregularities and other cosmetic evidence of age don't necessarily need to disappear.
Aggressive sanding and unnecessary removal of material can actually destroy some of what you're trying to preserve. Historic trim and sash components only have so much wood to give, and repeatedly sanding them back to perfectly fresh material can soften profiles, round edges and gradually change their original shape.
For House 173, that's an especially important distinction. We love the original woodwork and trim, so the goal isn't to make a 99-year-old window look as though it came from a factory yesterday. It's to make it sound, functional and attractive while allowing it to remain recognizably old.
What are the parts of an old double-hung window?
A traditional double-hung window is made up of far more individual pieces than it appears to be when everything is assembled. The two most obvious components are the upper and lower sash, the wooden frames that hold the glass. Those sashes travel vertically within channels formed by the window jambs, interior stops and parting beads.
Sash cords run from the sides of the sash over pulleys and down into hidden weight pockets, where they connect to cast-iron counterweights. Those weights balance the sash and make the window easier to raise and lower. The sill forms the sloped lower portion of the window opening and helps direct water away from the house.
Each sash has its own collection of components as well, including rails, stiles, glass, glazing putty and glazing points. Depending on the window, there may also be sash locks, lifts and other hardware.
Understanding these individual parts becomes particularly important during a complete restoration because many of them were fitted specifically to that particular window. That's one reason I labeled the pieces as I dismantled the House 173 window: after nearly a century together, I wanted each surviving part to go back exactly where it belonged.
Keywords
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