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.

PRESERVATION TIP:

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):

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