In a few weeks, I'm going to start replacing the single-pane windows in my 1970's house with Andersen 400 double-hung windows. I've been reading up on window installation and I think I have a pretty good handle on it, but there are a few details I wanted to ask about before I get started.
1) We are going to have the house re-sided later this summer, so I'm planning to install the windows and exterior trim but not repair the existing siding. I need to install new Tyvek first in the general area of the window, and the siding contractor will wrap the rest of the house when they remove the siding. For now, I need to cut away enough siding so that after the window and exterior trim is installed, there is still a few inches of Tyvek exposed so that they can overlap and tape the joints when they wrap the rest of the house. So, if I leave a few inches exposed between the new window trim and the existing siding, with nothing protecting the sheathing except Tyvek, will that last for a few months until they re-side the house?
2) The Andersen installation instructions show the window being installed with the sashes in place. However, I've seen many examples where the sashes are removed and just the frame is installed (to make it lighter and easier to maneuver). As long as I'm careful to keep the window frame square and plumb, it is generally considered acceptable to remove the sashes. I'll leave them in when possible, but I have some second-story windows were I think removing them would help.
3) Is there any reason to use metal flashing (aside from the drip cap)? All of the examples I've seen used the adhesive waterproof membrane products. The only exception I saw was in the "How to Flash Windows" topic in the "How To Guides" section of this forum.
4) The Andersen installation instructions say to leave the shims in place and cut them. However, once the window is secured by the nailing flange, the shims no longer serve a purpose, do they?
5) It it okay to install the exterior trim piece-by-piece? Or, is it better to assemble the trim pieces into a frame (on a table) and install it as one single trim unit? Or, is it just a matter of preference.