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Replacing Existing Aluminum Windows

These are the instructions for doing replacement windows where there are existing aluminum windows. The tools you need are to the lower left.

Tools                  Measuring

    Of course, the first step is to measure the opening for the replacement windows (above right). Do this by opening the moving panel and removing the screen. This will allow you to see which flange on the old frame sticks out the farthest. Measure from the flange that sticks out the farthest to the same flange on the other side of the window. This will give you the size of the clear opening you will have once you remove all the panels. Measure the widths at three places: top, middle, and the bottom. Then measure the height in the same way at three places. Give the measurements to Do It Yourself Windows And Doors and they will deduct 1/4" to 3/8" from your measurements to allow for any irregularities in the old frame, like it being out of square.  Your windows are then ordered, and will take about 2 weeks to receive. Once you get your windows it is a good idea to remeasure your opening and measure the new windows just to make sure everything is going to fit before you start tearing out the old window.

   If every thing checks out you are ready to begin. First, take out the moving panel and the screen. Then you need to get the fixed panel out. In some cases, like in our example, there are screws that hold in the fixed panel. Simply remove these screws (bottom left) then take out the fixed panel (bottom left middle). It may stick a little because of the caulking but a little prying should break it loose. With the fixed panel out you can now remove the meeting rail. On some windows, you may need to take this out first, then remove the fixed panel. Sometimes there are screws that hold the meeting rail in place. You can take these screws out and simply remove the rail. In the window in our example there are no screws for the meeting rail, so we had to cut it with a hacksaw (bottom right middle). In a few windows, you may have to break out the glass in the fixed panel, and then remove the meeting rail. Once this and the fixed panel are out you are ready to put in the new window.

Unscrewing panel    Take out panel    Saw out meeting rail    Remove trim

We had to remove the old wood trim because we needed to get flush to the old frame to give the new window a flush, smooth surface to be mounted to (top right). Put the new window into the opening to see how it fits, and to make sure there are no obstructions. If you have stucco you need to make sure the surface around the window does not protrude out past the old frame. With the new window in place, mark around the flange with a pencil. Remove the window, and if there are any places that stick out past the old frame scrape them so that they are level with the frame.

   In our example the house has lap siding. The old frame sticks out past the siding so that is not a problem. We did re-caulk the gap between the siding and the old window frame to make sure it was sealed well (bottom left). We then scraped the old caulking off of the face of the old window frame to make sure we had a smooth surface to attach the new window to (bottom right). Since the house was being repainted soon we painted around the window because it is easier with the new window off. Now your are ready to install the new window.

Caulking old window frame                            Scraping surface

    Caulk the surface of the old window very well (bottom left) leaving a couple of gaps in the caulking at the bottom near the old windows weep holes (bottom left middle). This will allow any moisture that might find its way behind the new frame to weep out. It is especially important to have a good seal between the old and new window at the top and on the sides. Now, with the surface well caulked, you are ready to install the new window.

Caulking window frame    Caulk gap    Put in new window    Level window

   Carefully insert the new window into the opening without disturbing the caulking (top right middle). Once it is in the opening, you can then press the new window firmly up against the old frame to squeeze the caulking and make a good seal. Make sure the window is secure then go to the inside. Try to center it in the opening as well as you can. You now should check to make sure the window is plumb, level, and square (top right). This is very important to insure the correct operation of the window. Shim if necessary. The window should be supported along the bottom, especially if it is a large vinyl window, since a vinyl window is flexible. Again, use shims if necessary.

   Once you have it positioned correctly then you are ready to screw it into place. Drill holes in the side of the frame for the screws to go through. You will need 2 ½” to 3” screws so that they can go all the way into the studs. Drive the screws in, being careful not to screw so hard that you pull the window frame out of square. Put screws in the sides about 18” apart.

Drill new window frame    Screw new frame in place    Interior window trim    New window exterior

   The last thing to do on the outside is to run a bead of caulking around the edge of the window trim for an extra seal against moisture getting in (remembering to leave a couple of gaps at the bottom). Now you are just about done except for trimming the inside. You will have a little gap on the inside between the drywall and the new frame. You can use wood moulding to cover this gap, or you can get a vinyl or aluminum trim from Milgard to cover the gap. If you really want to get fancy you could put wood window stool and jambs, and trim the opening with wood casing. On our sample window we use oak doorjamb to make the window stool at the bottom. We then used 1/8” oak plywood to finish the sides and top of the jamb. Then 1 ¾” ogee stop was used to cover the gap between the new window and the drywall. Finally we used 2 ½” oak 711 casing to trim around the opening and for apron under the stool. We now have a beautiful window that is more energy efficient and operates much better than the old one. Other than the inside trim it took less than an hour to complete.

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