Airstream Sub-Flooring Demo
The sub-flooring plywood is mostly secured by some wide-head phillips machine screws. Below is me trying to use the high torque of an impact driver to remove them. On MOST of them, this will not work. There is only so much torque you can put on a phillips head, and these screws have been rusting together with the frame for over 40 years. Here is the method that worked every time...
Step 1 - Strike the head of the fastener enough to bend it slightly to one side. Because the heads are flush with the plywood, you will need to use a chisel, pry bar, or similar in combination with your favorite hammer.
Step 2 - Knock it back straight-ish. You can usually do this by simply smacking the head of the fastener from the top.
Step 3 - Back to your trusty impact driver and watch as it magically rises from the rusty ashes having been given a major attitude adjustment. Just be sure to keep a lot of pressure on that screw (see body positioning above). You start slipping on a phillips head, and you don't have long before it's done for and you'll be forced to cut it off.
This is what we're dealing with. As you can see above, some of the framing members are superficially rusty, but some are past that and are in need of reinforcement or replacement.