I believe lucy is correct - most of the time, garden variety household mold may be no reason for panic. But this last year I've lived through a horrendous toxic mold experience in my condo, and when the combination of environment and individual really is a problem, it can be a very very serious problem. I've been out of my place pretty much all of 2008, and while much improved via extraordinary medical care (regular docs not much help) I'm still dealing with health issues - and it looks like some new hypersensitivities and allergies (gluten, argh, it was never a problem before) may be here to stay for life. Some strains of mold are seriously neurotoxic and for quite a while I was concerned I might have some damage... but lately I (choose to) believe 'twas other stuff like my battered but healing endocrine system which had fogged my brain. Part of what I've learned is that this is still pretty new terrain, and it's hard to point to any one person or source as the unquestioned authority. Everyone in the testing and remediation biz seems to say (and I don't doubt, genuinely believe most of the time) "the more casual guy who's half my price is worthless; the guy twice my price is just cashing in on toxic mold panic." Well, I did have to escalate up a few $$$ and expertise levels of testers & remediators to grasp the full scope of the problem and to get it fixed. But maybe the cheaper guys are fine in more typical cases; I dunno. So anyhow, I'd recommend, don't panic - you've most likely got nothing to worry about. But do get the place sampled and tested, find out what if anything's growing there. On the off chance you have nasties like stachybotrys and aspergillus, you're really so much better bailing out before you get really sick. There are website and labs with instructions for taking your own samples and sending them in. My only experience is with (a) remediators using solely their eyes, (b) a $900 visit from environmental inspector who took some air samples which all turned up negative (ha!), and (c) a $2000 visit from the super-duper inspector who's a global authority on this stuff, who did a variety of samples including sampling inside the walls and e.g. shaking curtains and thumping mattresses before taking air samples, and finally uncovered the horrors in multiple places in the condo - as in, four or five interior walls had to be removed etc. I guess my point is, if a $900 inspection can be such a joke, you may well be a lot better of with the DIY swab or tape samples. Here's a couple website which include some testing info. Please understand much of these sites concerns situations which are likely far more serious than yours. I'm not trying to freak you out, but take it seriously enough to diagnose your situation. http://www.inspect-ny.com/sickhouse.htm http://www.moldinspector.com/

You don't is the short answer. Hopefully you put in a sill pan and caulked the back of the jamb and head nailing flange. Get your trim in and be sure to incorporate a drip cap above the top section of trim.

Install the backerboard, waterproof, and tile up to/past the window. Install a Glacier White Corian sill over the existing with a good edge overhang and a drip slot on the bottom with returned ends which Corian jambs with Corian casing will die into. Silicone a Corian head jamb with casing into position and you've got a waterproof window. I'd charge you several thousand dollars, but it would never leak, need maintenance, or grow mold or mildew. And would look fantastic.

Do what you are planning to do. You REALLY SHOULD inspect the joists. Sigh. I know. It is a complete pain. I get it. Here's why. Vinyl STOPS moisture from moving UP into the air. And it stops dry air from hitting the wood. The foam pad (probably should NOT have been there...vinyl doesn't like regular underpad...but sometimes it allows for expensive mass-loaded vinyl) made it worse. Imagine the wood underneath is wet. In reality it should have been allowed to dry. A mold retarder could have been sprayed over it and allowed to dry once more. Assuming the joists underneath were NOT affected (former owner should have done it...but didn't) then the new layer of ply goes down. The vinyl goes down after the moisture levels prove everything is 'dry'. Now imagine NONE of that happened (sounds like it didn't). Now imagine SEALING IN the 'wet' in the wood by throwing down new ply. Now imagine sealing THAT up with foam (non breathable material) over the wood (wood does NOT like this...a vapour barrier should NEVER be used over wood...ever). Now you SEAL THAT set up with floating vinyl over top. Now leave it alone for a year or two. The moisture in the wood goes UP to the new plywood (like all chemicals, water moves DOWN it's own concentration gradient...it moves from wet to dry). That moisture soaked the top layer of plywood. That plywood tried to 'sweat' off the moisture but there was FOAM in the way. That foam was also sealed from above with vinyl. The moisture that wanted to sweat off, it got caught in the foam and dripped BACK DOWN onto the wood. More moisture (from below the wood...like basement or crawlspace) moved into the bottom plywood (cause it is drier than the air the moisture is in). That plywood moves the moisture UP where it hits the foam. Again MORE moisture drips down onto the plywood. This goes on until you unsealed the subfloor. You really need to check those joists. If you cannot see them from the bottom then you have to view them from the top.