All About Historic Windows

By Scott Sidler • October 22, 2011

4 pane casement window

For me, windows are one of my favorite, and at times, most challenging  (they’re one of the few parts of a house with lots of moving pieces!) aspects of a classic home. Windows truly are the eyes of your home and I have seen too many homes with a black-eyes over the years. A home and its occupants look out onto the world through these sometimes simple, sometimes complex contraptions to keep out the elements and let in the light. And the world learns a lot about your home by its windows.

A Brief History

In the first homes, windows were more than a decorative way to light the room. Originally, there was no glass, simply a crude opening designed to let fresh air in, smoke from the family’s fire out, and light the space. This lack of glass was the reason for the first shutters. After all, you didn’t want a hole in your wall during a rainstorm or a brutally cold winter, not to mention all the bugs. Eventually, glass came into the picture. First for the rich and the nobility and then slowly to rest of the masses.

Up until 1900, all glass was handblown and large pieces were very expensive. The expense and relative unavailability of large pieces of glass resulted in windows with several “lights” (meaning individual panes of glass) being the trademark of the days. In 1900 a new technique was invented and the predecessor to modern glass, called machine-drawn glass, was born. Hand-blown glass was mainly good for letting light into the room as the images seen through the glass were usually a blurry mess. Machine-drawn glass greatly improved the clarity and consistency of glass but was still far from perfect. As glass making skills increased, the size of individual panes increased as well resulting in new combinations such as 6-over-6, 4-over-4, 3-over-1, 2-over-1 and eventually glaziers could construct a window out of a single pane of glass.

Windows are typically described by their number of panes (6-over-6 has an upper sash with 6 panes and lower sash with 6 panes) and by the way they open (ie. double-hung has 2 sashes the open independently of each other whereas a casement window swings in or out on hinges).

MY LATEST VIDEOS
9 over 9 double hung windows

In 1959 modern glass, which is the type still used today, was invented and glass could be had in almost any size with a uniform thickness and flawless clarity. But those of us who like the special “glimmer glass” in our old homes that was the day windows with character began to die.

What Kind Do I Need?

Today you can buy windows in more forms than our forefathers could have imagined. Double, triple, even quadruple-paned windows filled with inert gasses like argon to prevent heat or cold transfer. They have become an efficient part of the house, yes, but when dealing with a classic home from generations past, an out-of-place window from the wrong time period can destroy a beautiful facade. Windows of yesteryear each had a purpose and served a function. For example, double-hung windows were designed with an upper and lower sash that could be opened independently of each other. The top sash (which on most older homes has been painted shut over the years) was designed so that in the days before air-conditioning, warm air could escape from the house and be replaced by cool air entering from the bottom sash.

The anatomy of a window (courtesy Old-House Journal)

Pre-war windows were also glazed with linseed oil putty to make the panes airtight. Caulking may last for years, but it doesn’t come close to the 80 year life span of properly cared for glazing putty. Also, being made from old-growth timber, original windows are surprisingly rot-resistant. I’ve had to completely rebuild only 2 windows out of the 32 on our 1929 bungalow, and those 2 were the only non-original windows in the house! The 2 replacements were a mere 20 years old before they succumbed to the elements!

So, before you decide to replace your drafty old windows, stop and think. They can be restored to their original appearance, working condition, and efficiency with period weather stripping (copper not foam or rubber.)

If you’re not sure about whether your windows are candidates to be saved, visit our resource page on How To Restore Old Windows

And someone probably thought this was an improvement!

Share Away!

62 thoughts on “All About Historic Windows”

  1. I have an old sash style screen frame for my kitchen window that I am sanding to repaint. I removed the little handles to make this job easier. There also was a strip that was screwed onto the top outside edge that I thought was a strip of wood but found it to be a piece of metal that is flat on the backside and rounded on the front or outside. Can anyone tell me what or why this was on there and if it’s necessary to put it back on once I have it all repainted ? This window is original to the house that was built in 1952. It gets set into place under a widow frame the same size above it. Thank you in advance for any help you could send my way, Scott

  2. Have 1820 white Brick Farmhouse…3 bay with center front door with transom. Want to replace vinyl windows with original style but not sure of how many lights: 2 over 2, 4 over 4, of 6 over 6?? Read that 2 over 2 started 1880’s but don’t know what would look good.. Checking out Marvin windows but husband said he might make them. He is very talented! Just not sure what color to paint sashes.

    1. Jo – I have an 1825 twin chimneys colonial farmhouse. Went to a workshop on old home restoration and learned that this era homes would have had 6 over 6 windows. Mine have been replaced with 2 over 2s. Would love to restore back to 6 over 6s, but dreading that little chunk of change – many windows. Good luck!

Leave a comment!

Keep the conversation going! Your email address will not be published.

*

This site uses Akismet to reduce spam. Learn how your comment data is processed.