Friday, February 19, 2010

Dealing with Antique Windows

I'm a big fan of old windows.  Despite Tom's penchant for energy efficiency, we have not replaced any of the old windows in any of our houses.  

I think the easiest way to muck up the historic fabric of a house is to replace the windows.  Old windows give the house such character, and replacement windows never quite get it right.  Often, new windows require that the size of the window openings be adjusted, which changes the entire look of the facade.  Even if the new windows fit perfectly, they usually look out of place, and if the original wooden windows are replaced with something that is not wood (vinyl or aluminum, for example), the entire house cries out for help.

Many people replace the windows in the name of "energy efficiency", but new windows don't really add that much to the overall energy gain.  Old windows often have a rating of R-1 to R-2, but the newer double glazed windows are usually rated R-3.  True, they will reduce the heat loss, but there are a lot of other ways to reduce heat loss that will have a much bigger effect.  Old windows that are properly maintained can be tight and reduce air infiltration as well as replacement windows, so the only difference is the heat loss directly through the glass.  So the difference in heat loss is so small that I don't believe the windows ever really pay for themselves.

Plus, the original windows are better designed.  On our houses, most of the windows are double hung (meaning, they open both top and bottom - or were designed to). On all the houses we have bought, we have never found a single window that actually operated well, and opened at both the top and bottom.  In our old house on Fulton Street, for example, we found that every window in the house was painted shut - top and bottom.

So on 62nd Street, just like in our other houses, we are fixing all the windows, so they all open at the top and bottom.  On a hot day, there's nothing like a double hung window - the upper window lets out the hot air, and the cooler air comes in through the bottom.  

Repairing old windows really isn't that much work.  This is how I do it:

First, I gather my tools.  I have a window kit that I use: a hammer, a flat bar, a screwdriver, a piece of monofilament string, a small fishing weight, a putty knife, a glazier's tool, a piece of bee's wax, an oil can, and a new package of sash cord.

With each window, I first remove the sash, both top and bottom.  I pry off the interior stop that holds the lower window in place, and then pull the window out.  Generally, the ropes are broken, but if they aren't I pull the ropes out of the side of the windows, letting the weights slide to the bottom of the weight pocket.  Next, I remove the parting strip (the little rounded wood strip between the top and bottom tracks) and then remove the top window. This often involves going outside the house and breaking the paint seal that is around the window - where the window has been painted shut.  

While the windows are out of the frames is the perfect time to replace any missing putty on the exterior of the window.  I scrape the putty to make sure it is not loose, and gently pry off any loose putty, and replace it with new glazing compound.

In order to fix the sash cords, I remove the access doors that open into the weight pockets.  On some windows, there are no access panels - this then means that I have to remove the interior trim around the window in order to access the space between the wall and the window, where the weights are located.  Then I remove the weights and take off the broken pieces of rope that are generally still tied to them.

Next, I oil the pulleys at the top of the window - there are four of them, two for the upper sash and two for the lower. The upper sash pulleys are generally in good shape, as the windows have been covering them, but often the pulleys for the lower sash are clogged and coated with paint.  If possible, I try to remove the paint from the pulleys to make them run easier.

Then I clean the channels for each window.  There is usually a lot of dust and cobwebs, and so I scrape it to get the channel smooth.  I take bees wax and run it up and down inside the channel, which will help make the windows glide easier.  True window restorers strip off any paint that is there and put linseed oil on both the window sash and the channel, but I'm generally not that fanatical about it.

The next step is running the new sash cord down through the pockets - the hardest part of the whole job.  There are two ways to do this: one is to feed the sash cord down from the pulley, and try to fish it down using a coat hanger bent into a tight hook.  This actually works pretty well - but an easier way is to tie a tiny fishing weight onto a string of monofilament, and drop it down through the weight pocket.  Then, tie the monofilament to the end of the rope, and feed it over the pulley and down.

Once the sash cord is pulled down, the weight can be attached to it (I triple knot the cord - the last thing I want is for it to come loose again), and reinserted in the weight pocket - making sure that the weight moves up and down freely.  

The step in this process that's easiest to screw up comes next.  The sash cord has to be cut to the proper length. The idea is to make it so the weight doesn't hit the pulley at the top nor the bottom of the weight pocket.  This is the step when I have to pay the most attention - I have mistakenly cut the cord with the weight at the bottom of the weight pocket (so it doesn't lift the window at all) and cut the cord up close to the weight (so the window couldn't move down from the top).

So what I do is pull the weight up until it is almost to the pulley, and then see how long the cord has to be to allow the window to be pulled all the way down.  Then I cut the cord, and knot the end so it can be fit back into the window.

Once both weights are done, they can be reattached to the upper window, and I reinsert the upper sash, making sure it glides smoothly. Then I attach in the sash cord to the weights for the lower window, replace the access doors, replace the parting strip, and reinstall the lower windows.  Then all that is left is replacing the stop, and the window is done.

Okay, maybe it IS a lot of work....

The problem is getting the motivation to actually DO all this.  But fortunately, on 62nd Street, we had no problem with motivation - all the windows were broken, and had to be removed so we could replace the glass.  In the front bedroom, for example, each window had a large bolt through it (where the glass had been) that held a 2x4 on the inside, and a sheet of plywood on the outside - the accepted way of boarding up a window.  Some of the other windows had plywood nailed directly to the exterior trim, or even to the window sash.  And most of the windows had security gates, some of which had been bolted into the plywood.  So just uncovering the windows was a big job - and then we generally found broken glass in the sash.
The casual visitor to the Delaney House will now find that all the windows on the main floor have been repaired, and they all open and close well.  We still have windows to replace - the windows in the bathroom and back room were both removed and replaced with (gasp) aluminum windows - so we have to find sash of the appropriate size to restore them.  

The windows into the basement have not been restored, and probably will not be.  Since the house will be lifted, the lower walls will be rebuilt, and the windows will not be the size needed. But we'll keep the frames and sash, and use them in another house whenever we can.  

The best part? We have another house coming.  The windows on the front of the Cheney Cottage are casement windows (a whole different animal), but I was happy to notice during the last inspection of the building that most of the double hung windows don't seem to operate. We'll wait until the Cheney Cottage is on 62nd Street, but there are more windows to do.


  1. Really?Thanks for the information. I love double glazing windows and sheds for both my company office and my house.It's very beneficial.

  2. Window replacement represents one of the more substantial investments you can make in your home. The replacement of old or under-performing windows can effectively reduce your monthly utility costs and give your home a bit more curb appeal. 
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