What’s up with glazing beads on steel windows and doors?

Share this post

Diagram | Joints | 2Fold | Glazing Bead | Thermal Break | Windows | Doors

Funny that you should ask.  It is one of the most misunderstood components in the construction of steel windows and door.  In almost all cases they are NOT made out of steel.  You wouldn’t know to look at them because they are painted to match the hot-rolled steel profile sections.  What you see is paint, not steel, but then again you never see the steel of steel windows either.

Unfinished Steel Rusts

Rust is bad.  Rusting all the way through is really bad.  During my lengthy career in the business, clients and their architects have asked me for unfinished steel.  I have always rebuffed them.  Yes, the natural grinder marks and discoloration of fresh steel is an attractive deconstruction component that has a certain appeal, but no matter what you do, the look doesn’t last;  It rusts. The surfaces on the inside can be maintained with periodic cleaning and oiling.  But down inside where you can’t see, under the glass and where the frame meets the wall, rust begins and won’t stop until it eats all the way through.  It is like steel cancer.  You don’t sense death until it is too late to do anything about it.

Is that all?

The other challenge to the “I want to see steel” dictate is that the glazing beads required to carry thicker insulated glass are aluminum.  Unpainted aluminum will never look like unpainted steel.  No way, no how.  Now some manufacturers offer steel glazing beads as screw-on beads with exposed screws.  This can be charming if you are a deconstructionist, but not so if you are drawn to steel windows because of their thin, sleek lines and minimalist aesthetic.

Steel Windows Have Aluminum Beads

Aluminum glazing beads are the de-facto choice because they can be extruded into intricate shapes that can engage with mounting clips under the glass that hide the fasteners and create a more refined appearance.  The glazing beads that capture the glass into the frame need to be mounted after the glass is installed. Steel windows are not subject to tolerances closer than ± 1/16” or more, the glazing beads need to be cut short by about 1/8” to be safe or cut to size at the time of installation to ensure a tight fit.  Steel needs to be painted AFTER cutting and other fabrication is complete to protect the edges.  Aluminum on the other hand can be painted in long sticks and cut to size as needed, but leave a shiny edge. However, if they are installed perfectly and you don’t look to close you hardly notice them.

Glazing Beads Are Independent Strips with Joints Everywhere

Glazing beads for steel windows are by design four individual strips of metal that are snapped or screwed onto the steel frames.  They are butted together, not mitered because they are almost impossible to install with miters.  This creates a steel window with visible joints that has a perimeter frame-to-sash joint, a sash-to-glazing bead joint, and four butted glazing bead end joints.  That’s a lot going on visually for what is supposed to be a sleek system. This joinery problem is compounded by the fact that the glazing beads are never perfectly on plane with the inside edge of the sash.  Also, they are almost impossible to align perfectly to each other in plane at the butt ends.  This butt problem exposes the silver aluminum ends and can look amateurish.  If you are fastidious you can take paint and touch-up each individual joint.

Accoya® Glazing Frames Are a Better Solution

Accoya® is a harvested wood that is treated in a special process called acetylation which makes it rot-proof even when submerged underwater for 25 years.  A 12 year growth and harvesting cycle in managed forests and vinegar-based processing make it the most environmentally friendly wood in the world.  Let’s not forget that it is almost always painted so you are seeing paint, not wood. However, if you want to, it can be left natural or stained to create a wonderfully warm aesthetic if that floats your boat.

Why Are We Different?

2Fold® is a steel window and door system that does not use steel or aluminum glazing beads.  In fact, it doesn’t use glazing beads at all.  It uses glazing frames and they are made out of Accoya®.  Glazing frames are a combination of four “sticks” made into a keyed and glued frame with no visible joint.  No butts allowed!  The glazing frame is the only thing you see on the interior of the sash.  The only visible joint is the sash-to-frame joint.  NO butt joints, NO sash-to-glazing bead joint.  This is how you create the truly sleek appearance that steel windows and doors promise.


We are committed to the environment.  That means not just the natural resources that make it, but the comfort and visual experience the product delivers to the occupants of your home or office environment.  Steel windows and doors with a twist . . . built from the inside out . . . 2Fold® Doors.

More To Explore

Join for monthly reminders of the latest blog posts.