Restoring Historic Windows

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How to keep what's good, and make them work. April 11, 2005

I'm in the process of restoring windows in an 1805 limestone house. The windows are single hung and 1-1/16" thick. The customer wants some type of window balance installed and weatherstripped the best way possible. I've looked at hidden sash window balances sold by Strybuc Industries that are installed in the sides of the sash and I'm thinking of using some sort of pile weatherstripping for the sash. Does anyone have suggestions on where to purchase these or other ways to do this? The customer is very fussy about not seeing any balances and would like a type of weatherstripping that will last a long time.

Forum Responses
(Architectural Woodworking Forum)
From contributor B:
You need to make your customer understand that the value of their historic property is in its original features... good and bad. Altering the way the windows were built may satisfy their desires, but will do no good for the true historic value of the home. Guillotine windows are part of history and part of the house. They shouldn't be altered. The one thing you could do with minor disruption is add some out of period sash stops inserted into the jambs. They can be unobtrusive and will hold the windows up without sticks. Many older homes with non-supported double hung windows had these added in the early 1900's.

As to weatherstripping, you are equally limited if you are going to remain true to the home. Many things can be carefully added so long as they can be removed, leaving the original building fabric intact. I've not seen many things that will do a truly good job of weatherstripping other than aluminum based strips. With a good aluminum primer and top coat of paint, you might get by with some of these.

I did a 10 year restoration on my last home and was successful in getting it placed on the National Register of Historic Places when I was done. I'm currently working on the restoration of a c.1925 small brick school building, and have begun the National Register application process for that as well.

So, as you can see, I'm a bit of a stickler for historic detail. If left alone by an egotistical current owner, a property will have the chance of being there in its original form for future generations. It only takes one person in the life of an historic building to ruin it for future generations.

From contributor T:
I gotta say I agree with the above advice completely. I moved into an 1880's era farmhouse in 1988 with the intention of renovating it completely. Now keep in mind that I do high end custom woodwork and also have built numerous period pieces in the interim. I felt as though I would know best what was proper, etc. Luckily for my house, I did not have the money to do this all at once, and in fact am still working on it. What time has conspired to delay, has in fact led me to a more proper perspective as to what is right for this house. Yes, not all changes are bad, and rare is the house that hasn't had modifications throughout its life, but something exists in these old houses that defies logical explanation that living in them for a period of time will reveal in a way that I really can't explain. My advice is to go slow! The proper way will come to you as you come to feel as though you truly belong there. If you're like me, even with the cold winter days and hot late summer heat, you'll come to actually feel sorry for the folks that live in those super efficient beehives that pass for the modern home.

From contributor D:
So, the sashes rattle a bit? I find it amazing that the windows of a two-hundred year old house shape up for reconditioning. In my experience with historical preservations, dating from the 1760s to the 1890s, dry rot and shrinkage have necessitated the authenticated remanufacture of nearly every part. Have you opened this can of worms yet? Is there not an original counterbalance to be brought back into play? Would oversized parting stops and resetting the stop moldings tighten things up? My approach would be to work the wood, first, and try to arrive at a point where I wasn't in a position of having to shop for a solution.

From the original questioner:
I understand more than anyone about historical integrity and leaving things as they are and always were. This customer is going to have these windows weatherstripped and some type of balances installed in the sash by someone. What I'm trying to do is supply him with a product which will satisfy his needs and wants and keep it as unobtrusive as I can. I'm like you and don't really agree with what he is doing, but it is his house and his money. I could look the other way and let the windows get "remuddled" by someone that has no feelings for the historical integrity of this project, or I can do my best to satisfy his wants and also please my mind, knowing I did my best. Does anyone have suggestions on the best way to go about weatherstripping these windows and adding balances to them, that wouldn't be seen? Thank you for all your advice.

From contributor I:
While I agree with all that has been said, like you I ran into a similar situation this past week. Remade a rotten window frame, reusing the old 1800's sashes. The top sash was stationary, housed in rabbet, supported by infill trim. Over that was a beaded trim piece (3/8 x 5/8) grooved for felt L-shaped weatherstripping to fit tight and slide against the lower operating sash. Instead of using felt, which I couldn't find and doubt if original anyway, I used silicone rubber weatherstripping from Resource Technologies in Baltimore, MD. Worked just fine, clients are happy. They also have special stripping for glazing sashes. As far as weights, check out They may or may not have what you are looking for. I just ordered some old seeded glass from them last night.

From contributor G:
I'm concerned about historic preservation, too, but making a living is also a necessity and pleasing customers is the reason I get return customers. I agree with contributor I.

Resource Conservation is a great place to get weatherstripping. I use sili-bead (silicone bead fixed in a groove cut with a router bit/laminate trimmer/angled handle toos, also available from Res. Conserv.). Normally, I think that silicone bead (comes in four or five sizes) is too sticky for sliding windows. I use it a lot on casements. But in your case, it might be just the ticket? I'd try one of the windows, as the bead does very little damage. The groove is cut in the jamb.

Here in S. Ca. I've installed weatherstripping and balances on lots of windows, but I cut the groove in the sash and use a small kerf-in product from Q-lon or Pemko. It's an open-cell foam with a vinyl skin, similar to the weatherstripping you see on doors. Very unsightly, but it slides well.

I've also installed mohair products from Pemko using a router and 7/16 in. bit and mortising the metal mohair track into the edge of the sash. You might be able to dial in the depth of this mortise to help control the sash, but that's pretty difficult to do.

All of the balances that I'm aware of are either unsightly or don't work well. My favorite is rope and pulley.

From the original questioner:
Thanks for the info. I'll follow up on the information you gave me and let you know how I make out. Have you ever thought of using a pile type weatherstrip that fits into a 1/8" kerf?

From contributor G:
My apologies for terminology. I think I worked in a vocabulary vacuum for 20 years and make up my own language. Mohair and pile are the same thing in my dictionary.

Resource Conservation: 410-366-1146

From contributor J:
Traditional Building magazine has always been a good place to find a source.

We used copper and pile for our double and triple hung windows.

From contributor M:
A major part of my business is historic sash restoration, and I can see the point of all those who've written before me. You don't say where the home is located, but I assume it's some cold climate so the weatherstripping is a relatively big issue. Resource Conservation makes a vinyl leaf seal that can be fit into the edge of sash, even narrow ones like yours. It's very slippery and takes up little room. Usually, there's enough slop between the frames and sash that just routing the slot for it to slip into is all that's necessary. It's invisible when installed, as it rides up with the sash. As far as balances go, there is no magic bullet that I've found. I wouldn't recommend the stry-buc units, as they're not going to last another 100 years and they will not be invisible. Retrofitting sash pins is not a horrible thing to do if that will satisfy your customer. If you have room (and usually there isn't) above the frames, I have used metal tape balances hidden in the head jambs once in a while. Pure historic restoration is great, but most people (including our State Historic Preservation Office) requires energy conserving retrofits for functioning buildings, done with care. Preserve what you can, and realize that the usual alternative is vinyl replacement windows, which cost a lot less, but won't be there in 20 years.

From contributor K:
I understand both you and your customer's concerns. Having come from the historic window industry, I would recommend a metal jamb mounted weatherstrip (small brads) made by a company call Dorbin. This product is available in galvanized and bronze. As for sash work required for this weatherstrip, simply remove about a sixteenth of an inch from each side of the sash, and cut a kerf in the edge (side) to align with the installed weatherstrip. As for the balances, I recommend spring coil balances (such as Pullman) located either in the side jamb or head jamb. As for the hidden balances (AX, I believe) as advertised in Stry-Buc catalog, these require removing a large portion of the stiles, and since your sash are only 1 1/16", I would not recommend these.