bathoom floor repair

After removing the tile in my bathroom, it appears to have a 1/2" plywood upper floor over a lower plywood layer of unknown thickness. Does this sound right? Is that a common construction method?
The upper layer of plywood is damaged in one section, due to water exposure (that problem has been fixed.) I want to replace the damaged area. I need to remove an area of at least 1' x 2' but leave the lower plywood layer intact. I need to cut it right along the wall. What kind of tool(s) will I need to cut the upper layer without damaging the lower? I regular circular saw won't get close enough to the wall.
Here's a small graphic showing the area. I want to remove some of all of the area within the dotted red line:
http://www.channel1.com/users/lsprague/bath3b.gif
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Maybe you won't need any tools other than that circular saw because you may not necessarily *need* to butt a cutting tool right up against the wall. That inch or two between wall and circular saw blade is, all in all, quite insignificant in demolition terms. The bigger issue for you is probably what was used to join the two layers of flooring together. If the previous owner was sensible and used wood/drywall screws or nails, you need only circular-saw right up against the wall, pull up the sawed-out section and then just pull up the remaining little 1-2" strip of the flooring still atached to the lower floor and stuck against the wall. If he used adhesive (cheap-assed or oblivious/lazy DIYers and hacks have been known to, for their own twisted reasons), you'll still be able to pull off that last 1-2" of top floor still left against the wall, but it'll certainly be tougher pulling it off the aubfloor than had the guy just used nails or screws.
AJS
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I've been off-line for a few days, sorry to have not followed up.

I didn't mention it in my original post, but I'm considering removing the entire upper plywood floor in order to lay down clean new plywood or cement board. So the question of how they are joined is important. There are visible nails in the floor, but I guess I should cut and remove the small area to make sure they aren't glued. The house construction is very cheap, and I find that they cut corners at every opportunity.
Thanks for your input. This is helping me get my head around the project.
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For a small area like that I think I could use a small jig saw with a longer blade and cut down in the area close to the wall. Then I could router out the rest of the perimeter at the correct depth, lift it and pull out the square.
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On 16 Feb 2004, snipped-for-privacy@xoxy.net (MaxAluminum) wrote in

I've been wanting to get a jigsaw - it would have been a useful tool to have a few times in the past, but I made do with a less apporpriate solution. I think it's time to get the right tool for the job.
Thanks for the suggestion.
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