Hello everyone, We purchased our home six months ago and I'm making things up as I go along, so forgive the potentially stupid questions. We have a bay window in our living room, and I have notice this past week some rot on the trim (which will be easy to replace I believe, I'm intending to use Azek trim) and also on the bottom "cover" for the window, against the two supports. The window has a Southern exposure. Eaves overhang it and I see no evidence that water is dripping from anywhere; i.e. I believe this is just a byproduct of general exposure. See the two photos below for illustration: https://picasaweb.google.com/erik.klepper/House?authkey=Gv1sRgCNn6qoK67aS1lAE#5628812299593225426 https://picasaweb.google.com/erik.klepper/House?authkey=Gv1sRgCNn6qoK67aS1lAE#5628812296760175538 Here are my assumptions, not really in order. 1. I cut some temporary supports from 2x4s to hold up the window. 2. I remove the two supports that are there now. 3. I cut a piece (or can it be pieces? currently there are two pieces there now, roughly 1/3 and 2/3s of the total 140" length) to fit the cavity 4. I install the piece and replace the supports 5. I replace the trim 6. I seal all the cracks with silicone caulk. 7. Everything is miraculously improved. So my questions: 1. Does anyone see a problem with using Azek for the trim? 2. I intend to use exterior grade plywood to cover the cavity - any recommendations for primer to seal it (I've used Zinnser for other applications in the past; I'm assuming this is appropriate) 3. Recommendations for paint over the primer? 4. Am I deluding myself to think that one piece of plywood to cover the cavity is doable (it's 12 feet total length)? Am I causing serious problems by using the same technique already employed (i.e. one four foot section, one eight foot)? I'm obviously assuming there's nothing worse going on in the cavity and as best I can tell there are no structural issues. Does anyone recommend anything exploratory before diving in? If so, would you have an idea as to how I can explore and if I find something really bad, how best to temporarily patch it up before I call in the cavalry? If you think I'm crazy to try this (I probably am) I'm happy to hear it. If you think I shouldn't do it myself, any idea how much this work would cost? Thanks very much for any help you can give. Regards, Erik PS - I'm cross-posting to other forums so I can get as many perspectives as possible.