I’ve contemplated this question in various forms over the years:

What exactly are customers looking for? 

You CAN replace glass in Caradco windows; easy answer, but do you want step-by-step instructions?  Probably not.  That’s what glass contractors are for.  I bet if you live in a relatively large metro area you have several glass contractors.  This is all they do is replace glass in Caradco windows and just about any other brand of window and door.  My answer is; replace the glass in Caradco windows with a new, reproduction Fenster replacement sash for Caradco. 

Let’s answer the first part.  Homeowners commonly don’t realize that glass can be replaced in their existing windows.  Think of it this way; the factory had to put the glass in the sash frame in the first place.  How did it get there?  If it went in, it can come back out the same way.  I think it’s important to explain the various ways glass is inserted into the sash frame to better understand how it can be replaced.  

In Caradco windows, particularly those from the 80’s and 90’s used a marine boot glazing system.  The glazing boot was a rubber gasket that fit around the perimeter of the glass unit and then sat in a channel around the sash frame holding the glass in place.  This system didn’t necessarily have a negative effect on the glass unit, but it DID cause premature failure of the wood sash frame.  Sash frame rot emerged as the prevailing failure of wood windows of the era.  Since then, glazing boots have become obsolete and replaced by a wet glazing system which is the standard for the industry today.  Oh, before I wrap this part up; why did they use glazing boots in the first place?  Cheap and easy to build of course!  

The wet glazing system (how Fenster Caradco sashes are built by the way) is the most common practice in today’s window manufacturing.  Wet glazing glues the glass into the frame using a typically silicone-based glazing sealant leaving a water-tight seal between the glass and frame while firmly securing the glass unit to the frame.  

While boots and wet sealants were found in the majority of wood windows, there were, or maybe still are other methods of glazing….but I was never a fan.

Glazing tape. 

Think of a thin foam tape adhering the glass to the frame.  Good for a few years until the tape disintegrates in the sun and heat.  Once in a while I’ve come across a window model or two that had the glass unit sealed directly into the frame channel with no boot and no stop.  Crappy design to say the least and basically rendered the glass unit unreplaceable.  So it can be impossible to replace glass on some windows, but not Caradco windows.  

How Window Glass Is Made

The next piece of this process I want to explain is where the glass comes from and how it is made. 

Another thing most customers don’t realize is glass is not brand specific.  You don’t buy replacement glass from the original manufacturer.  Unless your window is still under factory warranty, they won’t even sell it to you as a consumer. 

Nope. 

The dual pane glass, or IGU is sealed together at the factory by way of a spacer bar that sets the thickness of the unit and a butyl rubber sealant that seals the air space between the panes of glass.  You can’t simply separate the panes and replace just one.  The entire unit has to be removed from the sash frame. 

This is a good point to talk about WHY you need to replace glass in a Caradco window. 

Maybe the wood sash frame hasn’t rotted.  It’s the seal that has gone bad.  What happens here is that butyl rubber around the IGU gets brittle over time and cracks.  This allows air and moisture to seep into the air space.  Now while it seems to get in just fine, it doesn’t want to leave once it’s there, leaving the window with a foggy appearance or maybe even some moisture residue that never goes away.   It is also important to explain, most, not all, but most dual pane units have inert air in them; dead air space.  There’s no vacuum.  There’s no gas UNLESS the unit was made with an Argon fill that adds extra thermal and noise canceling performance.  Argon is a newer technology, while very popular today, the windows of the 80s and 90s probably didn’t have any gas of any kind in them.  

So how to replace glass in a Caradco window? 

We always have folk’s best interest at heart.  It doesn’t always make sense to buy a new sash from Fenster.  We very often recommend folks contact a local, residential glass company in their area under these circumstances;

• Maybe you just have one window that is foggy? 
• Maybe you are outside our delivery area and the delivery fee is cost prohibitive, again small quantity the driving factor. 
• Maybe Fenster doesn’t make your model?  Not an issue with Caradco, but the window industry is expansive.

Fenster replacement sashes are your perfect option for window repair when say; you have several that require attention.  Or, there’s wood rot.  Replacing just the glass does not fix wood rot on the sash frame.  You have to replace the whole sash when both seal failure and wood rot exist.  

Definitely, do NOT let a glass contractor replace the glass in a rotted frame.  You’re throwing good money after bad.  Instead, refer them to Fenster for our complete line of reproduction window sashes available for many major brands, Caradco especially.  You can find our complete catalog of replacement sashes along with all of our window repair products at; www.fensterusa.com.