Building a working frame for windows

Old 10-13-05, 08:10 PM
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Building a working frame for windows

I am new here so be gentle. I have an outbuilding that is wood but has no windows. I have been given some windows (without the frames) to put in. I know/understand how to put the windows in the building (12'X16' wood barn style building) but since there are no frames I'd like them to function like normal windows and move up/down. The windows are wood and have an upper and lower piece. (to me they are standard windows) Is there a DIY instructional guide somewhere on how to do this?

Any help is greatly appreciated.
Old 10-13-05, 09:27 PM
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Welcome to the forums here.

I don't know of a web site that explains it, so i'll do my best to try to explain how I would do it.

First, you need to determine how large of an opening your windows will occupy. If your sashes have locks, lay them on their side in the locked position and measure their combined height. If they don't have locks, just set them in the position they would be if they were closed, and measure the combined height. Then measure the width of each sash at its widest point.

Take these measurements and add 1/8". So let's say you come up with measurements of: 24" x 53 3/4". This will be the finished inside dimensions of the jamb you need to build. Your jamb will be made up of 4 pieces. (see illustration at: a head jamb, 2 side jambs, and a sill. The width of the jamb is determined by your wall thickness, so measure the distance from the outer edge of your sheathing to the inside edge of your wall. A normal 2x4 wall with 1/2" drywall and 1/2" sheathing would have a wall thickness of 4 9/16. This would be the width of your jamb, whatever it turns out to be. So, you would need to purchase 1x6 and rip it to the correct width. Using our sample measurements (above) the length of your head jamb would be 24" + 1 1/2". The length of your side jambs would be 53 3/4" + 1 1/8" to the short point of a 12.5 degree angle. (the side jambs will have this angle cut on the bottom, which is the same slope the sill will have). The sill will be made of 2x8 or 2x10 which has a 12.5 degree angle cut on both sides, front and back. The width of the sill is your wall thickness plus your face trim thickness, plus 3/4". (4 9/16" 3/16" + 3/4 + 3/4) or 6 1/4". The length of the sill is determined by the width of the window opening plus the amount of face trim that will go on the window. Let's say your face trim will be 3 1/2" wide. The length of the sill would be 24" + 3 1/2" + 3 1/2" (or 31") long. The sill will get 2 notches cut out of it on each side so that the side jambs can nail along side of it. The size of the notches is determined by both the width of the jamb and the size of the face trim. Using the above measurements, you would draw lines on the sill to show you where to cut the notches. On the 31" wide sill, you'd make a mark on the interior edge of the sill at 3 1/2" from each end, and that line would continue toward the front of the sill, but would stop at 4 9/16" +3/16" (to account for the hypotenuse of a right traingle, since the slope makes this measurement longer) and get squared off to the end of the sill. This will create a small "ear" on each end of the sill. The back side of this "ear will be tight against the sheathing once the whole thing is installed, and once the exterior face trim is installed, this ear should stick out 3/4" past the face trim.

Once the sill is cut out, you're ready to put it together. I nail through the ends of the head jamb and down into the top of the side jambs. Then I nail the bottom of the side jambs into the sides of the sill. Now the whole thing is ready to go into your rough opening (which should be about 3/4" taller and wider than the frame you just made.) In my opinion, it helps to frame the rough opening with a sloped rough sill.

Once the jamb is shimmed and nailed into place plumb and square, you are almost ready to install the sashes. First, install the exterior stop, a 1/2" x 3/4" piece. Install the top piece first, then the sides. It should be installed flush with the exterior of the jamb so that the window sash will be pushing up against the 1/2" dimension of the stop. Then install the upper sash in place. Older windows normally have a 1/4" deep, 1/2" wide dado down the middle to accept a 1/2" x 3/4" parting stop. (you can certainly do this if you wish) I thought it would be easier for you to glue and nail a 1/2 x 1/2 parting stop onto the head and entire length of the sides of the jamb. Push it against the upper sash and nail it in place. It should be snug, but not so tight that the upper sash binds. Measure to the inside edge of the jamb to ensure you get it on straight all the way around. Then install the interior sash. The remaining width of jamb will be covered by your interior stop, which might be about 1/2" x 1 1/4", depending on how much room you have left remaining. The window stool gets installed along the bottom edge of the sloped sill, then the interior stops go on top of that. When the face trim gets installed, you normally nail it to the exterior jamb and leave the entire exterior stop exposed- your face trim does not cover up the exterior stop (for fear you may nail the window shut!)

This is probably clear as mud, so if you have any questions be sure to ask.

Last edited by XSleeper; 10-13-05 at 09:38 PM.

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