An important part of the Preservation Carpentry curriculum at the North Bennet Street School is working with traditional window sash. In earlier posts we’ve talked a lot about restoring old window sashes, but what about new work? Or a sash that is too far gone or not worth restoring? The best option is likely fabricating traditional window sash yourself. The task may seem formidable, but with some practice anyone with the time and determination can do it. I find the work to be quite enjoyable.
Having worked on many historic windows, and new factory made windows I definitely prefer earlier period windows (17th and 18th century). In our modern ‘throw away’ world most folks look at an old wooden window with disdain and are eager to toss them in the trash and get vinyl replacement windows. If I had my way that would be a crime against historic buildings. The media has everyone believing that modern windows are far more energy efficient and easier to live with compared to old windows and that is a view based on ignorance and marketing greed. I spent several years living in a rental house with brand new replacement vinyl windows and while they were only mid-range windows they were disgustingly drafty, hard to operate, could not be fixed if you broke a pane, and took away from the appearance of the home. A properly built and maintained traditional window can last for 100 years or more — a claim no modern window supplier would ever dare to claim. The key to the system is that ALL the pieces of traditional windows were of wood and designed so they could be regularly serviced and easily replaced — and since they are primarily wood the replacement parts are easily fabricated. Good luck finding a part of a manufactured window that far into the future.
Even though wooden sash may look delicate, you’d be surprised how strong they really are. The profiles are designed to look lighter than they really are, and when you start to add the glazing etc you’d be amazed how solid the sash will feel. A properly built window will have the necessary flashing in place and will not have any drafts or leakage. As the seasons change, open up and regularly inspect your windows. If you are concerned about stirring up lead dust on old windows, contact a window restoration or preservation specialist — and make sure they are EPA RRP licensed to do the work in accordance with the law. If your windows are sound but you’d like to try and bump up the efficiency of your home’s envelope, consider adding traditional style storm windows — which can be either interior or exterior style or both and should be divided light patterns that match your existing windows — try to avoid the aluminum clad plate glass style they have in the big box stores.
If you are living with an old window in your home that sticks — remove and inspect the sash. The sides of the window sash (aka the stiles) should NOT have any paint on the edges that run against the jamb. If you find your sticky window has paint on it, you should look to remove the paint from that edge and the jamb (in accordance with EPA RRP regulations) and then carefully wax those surfaces. The paint has thickness which makes it harder to move the window and with humidity can often get sticky/gummy. Make sure that you are careful when removing the paint from your sash that you do not also remove wood — you can’t replace it once its gone and you don’t want to wind up with a drafty window.
The skills you learn when making a window sash can be applied to make other areas of woodworking. Above is a nice little wall hung mirror I made for my wife out of some extra materials I had. This same skills can be used to make glass cabinet doors, full size mirrors, cases, doors, etc.
If you’d like to see the process of building your own window sash, please check out the slideshow below which walks through the process (you can see many NBSS PC2 students in action):
6 thoughts on “Making a Case for Building Traditional Window Sash by Hand”
Good article Very nice greetings !
Great article. Here’s encouragement to go a few steps further and provide some details such as dimensions of stock that you used.
I do know that 18th c. sash was about an inch thick but changed to thicker 1-3/8 or thereabouts in the 19th c. but what about the widths of frame styles and rails?
Thank you. The stock used for that project was a standard 1 3/8″ thick for single pane glazed windows. The wood was high quality heart pine to be rot resistant.
Earlier sash muntins tended to be fairly wide and the lights (or glass panes) were fairly small. The stiles and rails were scaled to be of agreeable ratios. As time went on and styles changes in conjunction with technology improving to produce larger and larger sheets of glass the muntins got narrower and narrower — again with stiles and rails scaled appropriately. The 1 3/8″ thickness was not universal but a general standard for where things landed (a result of trial and error and eventually industrialization in victorian times), similar to how the stiles and rails generally landed at sizes that were a good mix of strength to size.
It might be a while, but I’ll work to make a post in the future about window sash evolution.
Thanks for the note,
Hello there! I had a question about material used to reproduce a sash. Im in the middle if taking on a sash window restoration and unfortunately al m ost all the wondows in the building will be too damaged to just repair. My question is, would walnut (besides being rather expensive) be a formidable material to remake the sash out of? Material cost is of no consequence, and ive already made a sash from white pine laminated in walnut but am not happy with the overall look and would rather remake it completely from walnut if it should hold up well enough. Thanks for your time, and any input would be greatly appreciated.
I don’t think I’ve ever seen a sash completed made of walnut and would not think it will weather well. At the very least Walnut will really bleach out in the sun and is not a terribly weather resistant woods. Most older sash were eastern white pine, southern yellow pine, white oak, cypress or similar rot resistant woods — preferably the heart wood and old growth versions of any of those species. I’ve seen many of those species stained to look like walnut on the interior and most if not all were painted on the exterior to blend the wood with glazing as one color. I would not recommend making the sash out of walnut. If you wanted to get fancy you could maybe mill all the profiled portion of the interior muntons (or a grill of it) in walnut and laminate that two a rot resistant exterior species, but that would be a lot of work for little return and possibly differential wood movement. (Sounds like that is what you may have already tried). Window sash deal with huge swings of temperature and I would not likely mix species like that, but if properly glazed and painted, you should not be able to see any of the exterior pine, only the exterior painted surface and whatever stained wood you have on the interior. Some modern windows mate exterior vinyl or composite materials to solid wood interior frames or grills but they have insulated glass units and more engineering behind them to deal with that.
I hope this helps.