All Copper Clad Windows Are Not Created Equal
Several years ago there were very few wood window companies manufacturing copper clad windows. Now there are quite a few, but very few of them have the experience of Woodwindows.com. Why is that? Simply, our expertise has been in the historic restoration of wood windows. We get a forensic look at what works and what fails in wood windows over a hundred years or longer. We examined over thirty projects with failed copper clad wood windows and discovered the problems common to almost all the failures. All of them, without exception used roll formed copper with soldered joints.
- Copper expands at a different rate than tin solder.
- The solder joints fail.
- Water gets trapped between the metal and the wood and deterioration begins.
- Field repairs are attempted and the metal becomes distorted the situation worsens.
- The trapped water creates a chemical reaction between the wood and the metal.
Window companies, rushing to manufacture roll formed wood windows, with no time tested experience, are blindly making the same mistakes that were made before them.
THE DISADVANTAGE OF USING ROLL FORMING
1. Cladding Wood Using Roll Forming: The wood components can be wrapped with a rolled formed sheet. This requires the use of special dies and the formed piece is slipped over the wood. This is the most common method and it is used for bronze, aluminum , steel and copper. The disadvantage to this method is there is no good way to vent the moisture build-up that occurs between the wood and metal. Over time this affects both the wood and the metal and will result in a failure. Here are some examples from a World famous New York City Hotel:
Here is an example of roll forming copper over wood. Notice what we see here. Water has entered between the copper sheet cladding and through freeze cycles has pushed out the copper. All sheet clad copper has the disadvantage of requiring soldered joints and over time most solder joints will fail as they have here.
Notice the sash corner pushed out. This is next to impossible to repair.
Notice the upper sash corner of this roll formed clad window. Now see it blown up:
Clearly we see the problem with roll forming over wood. The solder joint has failed. Water has expanded the cladding away from the wood. Any dings or distortions on the metal are next to impossible to fix. It makes no difference how thick the copper sheet is if it cannot protect the wood substrate.
That thick copper sheet is doing nothing to protect the wood window beneath the surface of the distorted copper.
2. Extruded Cladding. This is superior to roll forming as the extruded profiles leave room for proper venting between the wood and the metal. However it is very expensive and leaves very little flexibility of design. Ask your manufacturer for a special extrusion and grab your checkbook.
3. ArcClad by Woodwindows.com. This unique proprietary method is the most flexible and cost effective method of cladding any size shape or style wood window. It is a progressive build up from the wood surface through to the metal exterior. There is no moisture condensation and great durability, design flexibility, cost and longevity. It is also paintable and can be fixed in the field. All components are time tested and make a truly outstanding finished product.
The Superior Advantage & Beauty of ArcClad