DEAR TIM: We are buying two new smaller windows for a room in our house and want to add a custom stained glass panel to the assembly. One contractor says we can supply the stained glass and it can be installed in between the two pieces of the window's insulated glass. Another contractor says this is a mistake and that the lead in the stained glass would affect the insulated glass seal and cause a window failure. What is the best way to accomplish what we want? Is there a safe way that gives us the greatest flexibility? Alison, F., Toronto, CA
DEAR ALISON: It is a shame more people don't do what you are about to do. I have two windows and two front door sidelights that have custom stained glass panels that were installed after the units were installed. Each time a visitor comes to our house, they think the stained glass is original and is 100 years old. The truth be told, the stained glass panels are new, but built with the same skill as the craftspeople of ages past.
The best part though is that by adding my stained glass after the windows are installed, I get all of the benefits of new high efficiency insulated Low E glass and the beauty that only custom-designed stained glass can offer. You will be able to get the same. Many window and door manufacturers offer a variety of stained glass as an upgrade option for new windows, but that doesn't appeal to me and it might not to you. I just don't want to see my windows in someone else's house if you know what I mean.
The first contractor who said the stained glass can be sandwiched between the the insulated glass may be correct. Anything is possible and if you saw how insulated glass was made, it is not hard to include the custom panel. But I can see all sorts of challenges to this method.
For example, the size of the stained glass panel would have to be extremely precise, so it matched the inner dimensions of the insulated glass. If the stained glass panel was too big, it would cause enormous problems and if it was a tad too small, the gap between the leaded glass edge and the insulated glass seal would look tacky. Then, there is the issue of thickness. If the custom glass panel were not the same thickness as the space between the pieces of insulated glass, the panel might rattle or look funny. If just one soldered seam in the custom panel is too thick, the insulated glass seal may get stressed or may not seal at all.
I feel the best method is to install the custom stained glass panel on top of the existing insulated glass on the inside of the house. This method is simple, takes minutes and gives you enormous flexibility.
For starters, the custom panel is made by the stained glass craftsperson after your windows are installed. The measurements are taken by the fabricator and there is little chance of a mistake. The full beauty of the stained glass panel is seen by you and is not blocked by the glare from another piece of clear glass. If you decide to move, you can quickly remove the stained glass panel and take it with you. No one would even know the window had stained glass in or on it.
The method of installing these stained glass panels is very simple. The actual stained glass panel is made one-quarter inch less in both width and height than the actual distance between the edges where the window sash ends and clear glass begins. This spacing allows the stained glass panel to have a one-eighth inch space between the leaded glass edges and the edge of the window sash.
You must clean the window glass both inside and out until you are sure the window is perfectly clean and dry. Then, clean the new stained glass panel as well. With clean hands, gently tilt the stained glass panel up against the inside of the window glass and use two small brad nails on each edge of the stained glass panel to pinch it against the window.
The small brad nails are driven at a low angle into the edges of the sash no more than one-eighth inch so they do not hit the window glass. The shaft of the nail touches the edge of the leaded glass and holds it in place, so the gap between the stained glass and the window sash is consistent all the way around all edges. If the window is painted, you use paintable acrylic caulk to fill the gap between the stained glass and window sash. If the window is stained or is vinyl, you use clear silicone caulk. Once the caulk has cured, use a needle-nose pliers to remove the brad nails.
Many people don't realize that caulk is an adhesive or glue. In fact, the chemistry of caulk is nearly identical to many common adhesives. Once the caulk is cured along the edges of the stained glass panel, neither the panel or the caulk will fall out. The stained glass panel is very secure.
If you desire to remove the stained glass panel at a later date, you simply take a razor knife and cut through the caulk. Just place the blade along side the edge of the stained glass panel. It takes just moderate effort to cut through the caulk to the window glass below. Don't press too hard as the razor could scratch the window glass. Once the stained glass panel is removed, use a regular straight-edge razor to remove the residual caulk from the window glass.