Replacing metal windows with vinyl windows

In our past articles I talked about all the steps required to properly replace your old wood sash windows with energy efficient vinyl windows. I told you how to measure for the new windows. Then we discussed the removal of the wood sashes and parting bead. Finally, I told you how to install, seal, and trim the vinyl replacement windows. But, what if those old windows in your home are made of aluminum instead of wood? Is the process the same? No, it's not the same at all. So, the next few articles are going to explain the differences between replacing wood windows versus aluminum windows.
When discussing the proper frame style for replacing the wood sash windows, I explained the difference between new construction frames versus replacement frames. When replacing aluminum windows, there is another option we have to consider regarding frame style. It's called a "retrofit" frame. Let's go over each frame type. First, we have the new construction frame with the nailing fin. If you choose to go this route, you have to remove the exterior around each window opening, pull out the nails holding the aluminum window to the studs, nail in the new vinyl window, apply flashing, caulk, and re-install the exterior around each window.(I get tired just talking about it!)In addition to being a whole lot of labor, you can run into major problems trying to install the exterior product around each window opening. If your home has stucco, you have to try and match the rest of the stucco. It can be done, but not by you. Even most professional stucco guys can't get a perfect match. What if you have wood siding? Well, you can cut away 2" of the siding around each window to get to the nail fin, then you can apply 1 X 2 or 1 X 3 trim around each window. Certainly not as much work as the stucco home, but probably more work than the average homeowner cares to tackle. What if each window is surrounded by brick? Let's not even go there! You would have to remove the bricks, then re-install them all when finished.
Trust me, you don't want to replace your old aluminum windows with new construction vinyl windows. You want to use either the replacement frame like the one used to replace the wood sash windows, or something called a retrofit frame , that is popular in the west where stucco is a common exterior. Since the procedure for measuring is the same regardless of the frame style chosen, this article will discuss the proper measuring procedure, and future articles will explain the difference in the installation process for replacement versus retrofit.
If you look at the portion of the aluminum frame that goes around the window opening into your surrounding walls, you will see three separate "legs" that form two pockets. The outside leg and the center leg form the first pocket. Your screen and stationary panel will be in this pocket. The center leg and inside leg form the second pocket, and your sliding panel is in that pocket. Find the "leg" that is the widest on all four sides. When measuring the width, run your tape measure from the widest leg on the left to the widest leg on the right. This should be the narrowest measurement. Then, subtract 3/8" from that measurement. This is the width of the replacement window. Measure the height the same way. When measuring the height, measure as close to the center of the window as possible. This is especially important on windows wider than six feet, because the top wood header has a tendency to sag over time, making the center of the opening the narrowest. You don't need to deduct 3/8" from the height like you did on the width. 1/4" is fine. These are the dimensions you use when ordering your vinyl window. If you have any picture windows(windows without a vent panel), there will only be two legs and one pocket. You still measure the same way.
Next week I will discuss whether your home is a candidate for retrofit frames or replacement frames..
John Rocco has been installing
replacement windows since 1978
To learn more, visit How To Install Windows