Most of the time, you’ll want to use screws on your subfloor rather than nails. Nails can actually weaken plywood, whereas screws can easily penetrate without damage. They also form a more secure connection because of their shape, preventing squeaky floors and tightly holding the subfloor in place. That said, some contractors do prefer nails depending on the type of floor covering because they allow for more flexibility.

Bump-out additions can extend anywhere from 2 to 15 feet from an existing room. The right size will depend on how you plan to use the new space. For a cantilever bump-out, which doesn't require additional foundation support, the limit is typically 24 inches (2 feet). If a footing and foundation are part of the project, a bump-out can be much larger, even encompassing a whole room. It's also important to remember that many residential properties have limits on the total house size relative to the lot size.

Yes, you will need a jack for a rim joist replacement. To prevent sagging and facilitate the removal of load-bearing wood, you’ll need to relieve the pressure from this joint before beginning work. 

Due to hydraulics and other specialized equipment, a sill plate and rim joist replacement are not typically a DIY project. Hiring a professional structural engineer and experienced contractors is the best approach to replacing rotted sill plates and rim joists.

It’s best to use two screws to secure deck boards into every joist. Securing the boards to every joist makes the deck more structurally sound, while using two screws on the outer sides of the boards can help prevent warping and cupping.