Posts Tagged Glass
I did quite a bit of research before I embarked on restoring the windows, including attending a hands-on workshop to learn the process step by step. I blogged my decision on replacing v restoring in 2 parts, Part I at this link, and then Part II here.
Restoring wood windows is a process. Although the total working hours are maybe 10 – 12 hours per window, its all the time in between that takes so long. I let a glue-up or epoxy repair sit overnight to cure completely. Oil primer takes several hours before it can be painted. The glazing putty takes a full week until it develops enough of a skin to be painted. And then 2 good coats of paint at that. And then another full week to let the paint fully cure before I put the window back together.
So let me document my process. I learned a lot at a window restoration workshop, I’ve watched a ton of YouTube videos, and I even purchased a book from the Window Preservation Alliance. I should admit I didn’t follow the preservationists instructions to a T, but my goal was longevity and durability. My house isn’t going to be a museum. I don’t feel like I cut corners, but rather I made adjustments based on my past experience with furniture building & repair.
I’ll begin with an illustration that names the basic parts of a wood double hung window. This way I can document my process using the proper names for each piece, rather than my descripty thingy words I’m known for inventing. (Wordsmithing is a skill, after all.)
First steps first. I removed the interior stop, the trim pieces on either side of the window that keep the bottom sash from wobbling in & out. (Not defined above, the sash is the actual moving piece of the window that slides up and down. A double-hung window has 2 sashes, and upper and lower). The interior stops are basically the only 2 pieces that keep the bottom sash in place, other than being connected on each side to the sash cord – or not, because I found that more than half of my windows have the sash cords disconnected. They were either cut or the knots came undone. More on re-connecting those later.
The sash cords in my windows are only attached to the sash with a knot pressed tightly into a hole bored in the outside edge of each sash. Of the cords that were still connected, the knots pull out pretty easily, and I carefully let the weights pull the cord into the wall until stopped by the knot. If the knot was undone or too small, I pushed a nail through the cord to keep the cord from falling into the wall cavity. But I also removed the woodwork around several of my windows during the restoration process, either to better fix the already damaged plaster OR because the weight was already disconnected from the cord.
Reconnecting the weights later is so much easier with the interior woodwork removed, but that takes patience and skill to not completely ruin the plaster.
Next I carefully removed the parting bead, or as I call it parting stop. At first I was concerned about not breaking these pieces, but I later found that replacing this thin and pretty standard size piece of wood actually made my windows operate a lot better once reinstalled (I found new parting stop as a stock item at my local Ace Hardware). This piece is what separates the upper and lower sash as they slide up and down. Although they are supposed to be “tension fit” into place, I found most of mine had been nailed in place at some point, probably because they became loose over the decades. With the parting stop gone, the upper sash can now come out.
At this point it’s still fairly early in the morning on my typical “window Saturday,” so I would make a fresh cup of coffee and then begin scraping the paint on the outside of the window frame (but not drinking the coffee near the paint scraping – lead safety is a real thing). I haven’t restored any windows that have a storm in place, but otherwise these would have to be taken off at this point to fully scrape the outside trim. This way I could get the entire window frame scraped, removing nearly a 100 years worth of built up paint. I fill any major holes or cracks with wood epoxy, but I’ll worry with the small cracks and nail holes & sand right before I prime & paint. To secure my house, I simply cut a piece of plywood and screwed it into place to the outside of the window frame. For added “security” – I use that term loosely – I used star-bit screws so if someone tried to remove the plywood, they would have just a little more trouble trying to break in. Like, they’d have to make a trip to Ace Hardware to get the right bit and then come back to find I own very little worth stealing. So far I’ve worked on the windows at the back of my house, so they haven’t been very visible from the street. Next summer, however, I might work on a little better security so every car driving past doesn’t assume I’m an easy target.
I’m refinishing my woodwork to it’s original stained color on the inside of the house, so I spend the time scraping the paint on the inside woodwork as well. I am much more careful on the inside trim because I don’t sand it down to bare wood; scraping the paint mostly removes the original varnish, but the wood keeps a lot of the stain color underneath. If I would sand the color completely out, it would be more difficult to achieve an even rich mahogany color when I re-stain it. I find staining over whatever color is left in the woodwork achieves a beautiful color that is spot on to the woodwork’s original color (seen in the few spots where the woodwork was not already painted).
Then I focus on fixing each sash. The level of deterioration determines how much work the sash needs. I hear rumors that some window restorers only have to touch up missing glazing putty and then sand and repaint. Rumors, but not my story. I have windows where the glass is only held in place by the glazing points – almost no putty left. As carefully as I can I remove the remaining glazing putty with either a sharp chisel or another sharp tool. The glass becomes loose, but there are still metal glazing points holding it into the sash. I learned the hard way that missing even one of these little metal pieces will crack a window when you try to push the glass out. I remove each glazing point with a sharp pair of needle nose plyers, always pulling away from the glass and not putting pressure on the glass. The glass usually pushes out pretty easily, and I write on the exterior of the glass with a Sharpie so I know I reinstall it the exact same way. I’ve come up with a system:
04 Ext. ↓ ↑
04 is the window number (I numbered each window in my house, even with 2 windows tore apart it can get confusing). Ext means the exterior side of the glass. The first arrow (↓) tells me which sash (upper or lower), and the last arrow (↑) tells me “this side up,” meaning this is the top of the glass as it goes back into the sash. I know it’s old glass, but I find that Sharpie stays in place until I wash the glass with glass cleaner. It doesn’t accidentally rub off or fade while the sashes are being repaired & painted.
Now the wood sashes in my windows have not been in great condition. Very loose joints and even some rotted corners where some idiot before me used nails & screws to keep the frame together. Originally the sashes would not have had glued corner joints. Each corner was made from a very tight tongue and mortise join, with two small metal pins nailed into place.
But I use exterior wood glue and epoxy pretty liberally to make sure the joints are secure and the sash will last another century. In the sash above, I nailed 2 small brads to hold the joint along with the clamps, and then drilled a hole 3/4 of the way deep and glued a wood dowel into place. I haven’t yet had to do a “dutchman repair,” but there’s are several great online tutorials in case I find a spot rotted so badly that epoxy won’t cut it.
Then it’s more scraping paint on both sides of the sash. I fill any remaining nail holes or cracks I find, then sand it smooth.
When I bought this humble bungalow (over a year ago!), one of the features I found most interesting was the distorted glass in each of the original wood windows. “Wavy” glass is an understatement. When I really study them, there are bubbles, circles, lines, and other imperfections in every piece of glass. I still remember the 1st or 2nd time looking at the house with the realtor, how beautiful the light danced on the walls through the imperfect glass. Of course, the deterioration of the windows and the rattling glass was one of the scariest features. While the whistling of the wind and drafts around each frame this past winter was an expensive feature.
Working in the field of downtown development, I’ve been lucky to attend dozens of workshops and training events about the importance of building preservation and wood windows. I’ve heard them use the fancy phrases, how wood windows are part of a building’s historic fabric, the vast difference between old growth wood and dimensional lumber available today. And more recently I’ve experienced how downtown revitalization grants can help with almost every aspect of restoring a historic building facade, but the Historic Preservation Office is adamant that grant funds will pay to have wood windows restored- not replaced.
So over the winter months — as I was reluctantly turning up the thermostat, putting more of my paycheck into the “heating” budget, and watching the shrink-wrap plastic flicker from the cold air blowing in around each window — I began seriously researching the best option for my house.
I do advise CAUTION here – only begin typing the word replacement, vinyl, fiberglass, aluminum clad, or easy-to-clean in any internet search engine and the only results will be replacement window companies – hundreds of them claiming that all of my home’s energy problems will be solved if I toss the old windows into a dumpster & install the cheapest vinyl windows on the market. Others claimed I could stand on the windows (before installing them I assume?), $99 window sales, solid vinyl sash frames, one finger open & close, multiple warranties, and even custom colors for the exterior to match any decor.
But then I searched for an answer to my real question, “wood windows restore or repair.” The results were countless forums, threads, magazines, blogs, and even energy efficient building research. They all said the same – wood windows, when restored correctly with the right materials, adding a mix of original and modern weather stripping, and with a quality storm window- will match or even outperform replacement windows in energy efficiency. Add to that the embodied energy already in the existing windows, the un-matchable strength of 100+ year old lumber, and the compiled data of historic home sales that show original windows add significantly to home & neighborhood values. Or do a little more online digging and read how 5 of the largest US replacement window manufacturers were recently charged with class action lawsuits against their false & deeply exaggerated “statistics” of energy savings they claim their windows will achieve. Eventually these 5 companies settled with the Federal Trade Commission to delete the language from their advertising when they can not consistently prove the numbers to be true.
Last summer I had 3 different window salesmen stop me while working outside or mowing the lawn. They tried their hardest to come inside, sit down and talk about their products, the “50% – 55% energy savings I could experience.” When one salesman revisited this spring, I asked him a simple question:
“These windows have lasted almost 100 years; Can you sell me a replacement window that will last that long?”
The answer is no. Many of the highest priced residential replacement windows offer only a 20 year (and very limited) manufacturers warranty. Even then the warranty is often for only the mechanical operations of the window – NOT on the low E gas seals, air-tightness, or their bold energy efficiency claims. And all the research I’ve read from professionals in the historic preservation world say property restored wood windows can last another 100 years (although with painting & glazing repairs in the middle at least once).
I read every online article, blog, and discussion thread I could find. I watched YouTube videos late into the evenings, trying to take notice of the slight differences from one professional’s process to the next – mostly minor, or they each have a different favorite method for steps such as removing paint, making repairs, etc. But the process is the same – remove all paint, remove all glazing, carefully remove glass. Sand, re-glue, prime, reglaze, paint, and re-install.
But I still had so many unknowns and fears about taking this on by myself: the details of weather-stripping (bronze? silicone bulb? vinyl flange? brush.., foam.., felt??) And what are the differences between the many types of glazing compound. Is that the same as glazing putty? And where do I find replacement sash cord that won’t stretch over time, or combination lift/sash locks? Oil or latex primer and then paint?
It was perfect timing to learn about a hands-on wood window workshop taking place in Columbus back in March, hosted by a new historic preservation group somewhat affiliated with the organization my workplace is involved with. Two days, hands on learning, BYOT (bring your own tools), and learn the entire process working alongside 3 professionals. Sign me up.
In Part 2 I’ll describe the workshop in depth, and the basic tools, methods, & products the professionals there taught us – based on each of their 30+ years in this work. But one blog I have found to be very helpful – and exactly step by step in line with the teachings from the workshop – is The Craftsman Blog. The writer is owner of a historic home restoration company so of course the entire blog is a very full resource for old home enthusiasts. But his specific posts detailing window restoration are almost a printable instruction guide. Thank you Scott for all the incredible content you share, I have learned so much from your blog!