How do I measure for a window replacement that was installed from the outside?

Question

My windows were installed from the outside and the siding was installed over it. I have already replaced one window, but my measurements were wrong making the window too small. I had to frame out the window to make it fit. Of course, after the window was in, I installed trim around the outside window to hide where I cut the siding away. It looks nice, but I don't want to frame all the other windows. All the instructions on the Internet are for windows with sashes or windows installed from the inside. Thanks for any guidance anyone might provide!

Do I measure flange to flange or just measure what I see from the outside? Am I making this too complicated? It took so much longer with the first window because I had to frame out the window as the ordered window was too small.

Answer 1

In the first place, you strip off the siding around the window. Then the outside trim, down to the basic window, then measure the exact window size, all you have to do is cut around the window with a sawzall (the nails holding in the window, sometimes four to eight) then take the window out. Put the other window in, the same size as the one you took out, reverse all procedures you started with.

Answer 2

OK most windows come in a standard like 36 48 60 70 some come in half like 36 1/2 ,48 1/2, 60 1/2, 60 1/2 should be able to measure window and guess.... and get it right .... i do house layout.. and that's pretty much standard unless its a custom window then it might be some what different try measuring the windows again see what you come up with measure from the wood not the glass check the opening and then measure the window and see what you get bet that will work for ya