There are a few basic types of materials that any renovation project like this needs: structural members to reframe walls and floors, and sheathing material to cover and tie them together.
Thin floor boards salvaged from another house can be used for structural framing. Only 1/2" in thickness, they're far too flimsy to use singularly. I get to the task of making my own laminated beam, or glulam, by attaching several of these to each other to form a larger, more robust member.
Very smooth surfaces are needed for the pieces to adhere well enough to each other. The flimsy boards don't do well through the planer, so each is sanded with hand tools - not ideal, but does the job.
After the boards are laid out a weatherproof wood glue is applied in a thin and even layer to each face, and the boards are clamped with every clamp available to make sure there is 100% contact between surfaces. Wood glue ends up being much more workable and thin than construction adhesive, so will likely be a better choice here for the raw pores in the wood.
By using several layers and offsetting them, a much longer beam can be made out of shorter pieces (though these boards were already 16'-18' long), so very substantial spans can be achieved here - namely reframing the portion of roof which has rotted.
The majority of the first floor and basement walls are covered with a thin faux wood paneling - a cheap material meant to simulate the look of a natural wood finish. It doesn't provide any real benefit other than aesthetic, and its lack of authenticity is easily noticed. In water damaged areas, moisture and mold are likely to lay behind them, too. All that considered, and a personal vendetta against fakeness in materials, I've started removing these panels and considering other uses for them.
Several portions of floor and wall will need to be resheathed - the leaking water over the years having rotted them away.The sheets are very thin, and aren't very useful as is.
Having a number of full size sheets, I've begun another laminating experience, taking cues from the composition of plywood. Three to four layers of the faux wood paneling, sanded smooth and glued under pressure, will make for a strong 3/4" thick sheet which can be used for subflooring in place of the existing planks. Type of adhesive and methods of applying pressure are still being worked out.
These experiments are vastly more labor intensive than going to Home Depot and buying a relatively inexpensive readily available product for the same use. But for the needy and for the sake of reinstating value in what we have, they can suffice.