Continuing the restoration of window frames and hardware I talked about in my last post, this entry completes the restoration of the frame portion of the project bedroom windows with new cord on the sash weights and weatherstripping that will keep these 86-year-old windows comfortably draft-free and energy-efficient.
Sash Cord and Weights
There is just something genuine about the mechanics of old double-hung windows. Their simple combination of pulleys, weights and rope achieves an amazing result: leveraging gravity to hold something up. Plus today’s windows with vinyl friction jambs just can’t compete with sash weights for smooth operation or longevity. Embrace your weights!
To ensure a long-lasting restoration, I replaced all the sash cord with new 1/4″ nylon cord. My local True Value hardware had both nylon multipurpose rope and cotton-over-nylon sash cord. I chose the nylon for its superior strength and resistance to rot, though the look of the nylon casing sacrifices a bit of authenticity.
To tie the sash cord to the weights, I picked the bowline knot from my repertoire of old Eagle Scout skills. The bowline is a good choice for this application because it forms a loop that does not close– once the knot is tight, there should be no slippage that could take the weights out of adjustment.
The tied weights then go back in their pockets alongside the window jambs, with the sash cords fed up and over the reinstalled pulleys.
My principal reference for how to restore these windows is a book I’ve mentioned before: “Working Windows” by Terry Meany. Meany recommends a combination of modern and traditional weatherstripping for old couble-hung windows that I have implemented here.
For the lower sashes, Meany calls for traditional spring bronze, sometimes called brass spring, nailed to the jambs. Although this material is less commonly available than it once was, I had no trouble finding it at a store right in my neighborhood.
Installing spring bronze is a bit putzy because it must be nailed every inch-and-a-half or so. It’s also important to use a nailset to sink the nail heads a bit or they will gouge up the sides of the window sashes. My spring bronze is cut to one inch longer than the height of the lower sash and trimmed to a curve on top to prevent damaging the sash or bending a corner on the weatherstrip when the sash is fully opened. To create the spring action in the spring bronze, run a slotted screwdriver down the groove you’ll find next to the nailing edge of the weatherstrip.
If you look closely at the picture above you’ll see a section of white vinyl weatherstripping for the upper sash in addition to the fully-installed spring bronze. The reason spring bronze isn’t ideal for the upper sash is that there is no way to use it around the pulley. Adhesive-backed vinyl “V” weatherstrip fixes that problem– here’s how:
First, some background: the vinyl weatherstrip comes as a roll, typically sold in nice, round, 17-foot lengths. The True Value hardware nearest to me had it in stock in both white and brown for just a few dollars a roll. Also, you may see it labeled as 7/8 inch wide, but this is the unfolded width. Folded, it is… wait for it… half that width (7/16″). Because it is installed folded, 7/16″ is the more useful and accurate width dimension.
Unlike the spring bronze, which was installed on the jamb of the window frame, the adhesive vinyl is attached to the exterior stop. The exterior stop is the part of the window frame that forms the outside edge of the “track” that holds the upper sash. Correctly installed, the “V” of the weatherstrip will point to the corner. The following picture shows proper installation and how this fixes the “pulley problem” I mentioned above.
When the upper sash is reinstalled, I will close the “V” as the sash is positioned. The weatherstrip will then press against the upper sash and prevent air from infiltrating through the space between the side of the sash and the window frame. Although the vinyl material and adhesive attachment method are far less durable than the spring bronze, the upper sash is also a less demanding location than the lower sash, so I expect it to hold up well.
Paint removal was the most laborious and hazardous part of the window restoration I’ve undertaken so far. But if you have old double-hung windows that don’t require paint stripping– or if you can hire someone else to do that part of the work– I think many people would find weatherstripping an easy and affordable DIY project.
Disclosure: I was one of five bloggers selected by True Value to work on the DIY Squad. I have been compensated for my time commitment to the program and my DIY project as well as my posts about my experience. I have also been compensated for the materials needed for my DIY project. However, my opinions are entirely my own and I have not been paid to publish positive comments.