BridgeMan

Copper napthanate is the good stuff, strongest that can be purchased/applied by laymen without a license. But I suspect, way overkill for your situation. Replace the subfloor if that's what it takes to make you sleep better at night. Me, I'd look at a less labor-intensive approach, as in just giving it a shot of bleach, then filling in any low spots with Duroc water putty and sanding smooth before putting down the new floor surfacing.

dw8

nealtw and BridgeMan:
Thanks for feedback.
Did some checking about copper preservative. WIKI had a great writeup.

To complicate matters more, the crawl space under the house is actually a closed plenum
that is used for heating/cooling since this originally was a solar home. Years ago when
termite treated, they used a borate solution - instead of copper - over concerns of potential health
effects other insecticides might have. Doing some more research on this today.

BridgeMan: "Duroc" hadn't even thought of that. Have seen it in small cans (in fact I have a small can of the stuff), but for a floor I would think you would need to buy it in 5 gal buckets

BridgeMan

I've only used Duroc for localized leveling (small areas, less than a few inches by a few inches, or less). Wouldn't recommend it for leveling large areas--best to use bagged floor levelers for that (cementitious products you add water to).

dw8

BridgeMan: Thanks for feedback. Familiar with self-leveling compounds for concrete.