It is said that a good home depends on a solid foundation. Nothing could be truer. Beyond that though, the frame - or skeleton - of the home probably is the second-most important part of modern building construction. Everything within it is connected directly (or indirectly) to the frame of the home. The exterior wall covering is connected to the frame. The roof covering is connected to the frame. The wiring, ducting, plumbing, sewer, security system and insulation are all connected to or supported by the home's frame. On the inside of the home, the wallboard, doors, windows, cabinets, hand rails, stairs, stair rails, light fixtures and even the flooring are all connected to the frame. No doubt about it, the frame is an integral and highly important support system.
If the frame is weak or crooked, the result will be a flimsy home that looks a mess. We don't suggest that the frame be built to the exacting tolerance that one might find in cabinet construction, but walls that are plumb (level up and down, perfectly vertical), level (horizontally) and square to each other are a must. The exception: For remodels and additions, it is most important to match what exists, even if it means that the new wall must be built slightly out of plumb (tilted). It would look odd if a perfectly vertical wall was built to extend one that was slightly tilted. Actually, with a remodel, sloped floors and tilted walls are common. When these conditions exist, and when they aren't too extreme, it is best to align the new to the old. In cases where the existing condition is extreme, it is wise to repair or adjust and then add on or remodel.
In new two-story construction and multistory additions there are two basic framing options: platform framing or balloon framing. With platform framing the walls begin and end with each floor (or platform) level. Each floor marks the beginning or end (top or bottom) of the wall (i.e., after the first floor is built, then the walls for that floor are built. Then another floor is built and more walls are added. Finally, the ceiling and roof are constructed. With balloon framing the walls are completely different. They traverse continuously all the way from the foundation to the roof - unbroken, nonstop. Each of these framing systems has its own advantages, although, today, platform framing is the most commonly used system. Platform framing is easier to construct, less expensive (shorter studs are cheaper than the big long ones) and safer too. No scaffolding is required for platform framing, and in most instances the walls are easier for the carpenters to lift and generally easier to handle. Balloon framing, on the other hand, provides a better base for stucco and masonry wall coverings. The longer studs associated with balloon framing are less apt to contract to the same extent as their shorter platform-framed brothers, thus providing a far more stable base for finishes that tend to crack when the frame shifts, such as stucco, plaster and stone or brick. With balloon framing the floors are built after the tall stud walls are in place. High-quality wall-stud material is hard to find and comparatively expensive. A ledger which constitutes the rim (or perimeter) of the floor is "let-in" (inlaid into) the wall framing. Then the floor-framing members are either laid atop the ledger or attached to it with metal connection devices called joist hangers.
If you intend to add on and discover that your home is balloon framed, don't fret. You can still platform-frame the addition. The systems are compatible. Whichever system you choose, be sure to use extra connectors. If the code requires five nails into the end of a header, use six. If it requires three nails in each block, use four. When it comes to connections, more is better. For metal connectors be sure to fill every hole with a nail. And be certain to use the correct nail. Today the most common framing nail is the 16-penny sinker.
Also, even if you begin with the very best framing lumber, keep in mind that it has a tendency to shift, twist and curl once it has left the lumber pile. Once assembled and exposed to nature's two most devastating elements, sunlight and fresh air, green framing lumber will begin to dry out and change shape. Just before installing drywall it is a good idea to check all walls to ensure that everything is straight.