I am replacing a wood window that was build in the early 1900's. The original installation was really odd, it was mounted in place by the trim boards. Two nails on the outside of the trim into a stud and two nails into the wood window frame were all that held it in place. I ordered a replacement window but before I install it I need to cover and seal the 2x4's that are in place, right? I am thinking I need to put some flashing over the studs and then put some 1x6 around the perimeter of the window, then install from there. Am I on the right path with this? I am fairly handy but this was my first window replacement so the installation curve ball is throwing me off.

I found the link below about a guy that has done this before but it seemed a bit confusing.


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  • Should I set it back from the exterior and trim some stops in place or can it be flush mounted? Is it just a matter of preference? Aug 8, 2017 at 21:53

1 Answer 1


I wish this board would let me say this, but a mod deleted one of my posts recently for being too short. However, here's the answer -


Flash the framing with some wide flashing tape, and build you a frame FOR THE NEW WINDOW, not the frame where it's going. That make it easier to install the replacement window to your liking. Just shim your new frame square (plumb/level it if possible, but not necessary), and install the new window with the screws provided.

If this is your first, make sure to tighten the mid-frame shim knobs, or shim the middle of the replacement window to where the sashes run snug.

  • 1
    Stops will help more than just caulk alone. Keep the window as close to in-the-house as possible.
    – NPM
    Aug 8, 2017 at 21:52
  • Thanks for pointing me in the right direction! Is 100% silicone the best for exterior caulk? Aug 8, 2017 at 22:28
  • 1
    If possible, pick one of the newer elastometric caulks. They work best, and are paintable. Silicon isn't paintable. A little pricey though. However, Silicon works great if you aren't going to paint.
    – NPM
    Aug 8, 2017 at 22:33
  • I found some 100% silicone by GE that is paintable, I will see if I can take it back to get the other though. Spray foam for the gaps or is there something better? Aug 8, 2017 at 22:43
  • Would you recommend using treated wood for the frame, just in case there is a leak? Aug 8, 2017 at 22:58

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