Hidden Kitchen Systems: Structural Integrity
A house and any other building is an engineered structure designed to handle stress loads and great weights. Foundation, wall, floor and roof framing and sheathing all work together to provide a structurally sound and weatherproof skeleton and envelope for your home. Properly designed and constructed homes are very solid and offer the secure knowledge that they will last a long time and be safe to inhabit.
Because most homes today are wood frame structures where stud walls support floor joists that act as platforms for upper floors and roofs, you cannot freely assume that any wall is removable during a reconstruction process. You may wish to double the size of your kitchen by taking over an adjacent space or building out from an existing one. In both cases you’ll be removing a walls or walls and potentially compromising the entire structural integrity and safety of your home. Some walls, known as non-bearing or curtain walls, serve mainly as room dividers and do not carry a significant structural load. Others, known as bearing walls, carry much of the weight of everything above them.
Bearing Walls
Moving or removing a bearing wall can be expensive and requires the construction of another structure to replace that wall’s load bearing capacity. This must be done by qualified carpenters and contractors who understand how to figure loads and spans and design solutions that allow you to remove a wall.
Bearing walls typically run perpendicular to or across the floor joists of the upper floor, supporting these joists in the center of the house. Determining the direction joists run is the first step in determining whether a wall can be easily moved. Walls running parallel to floor joists are generally curtain walls. The problem is that in certain situations it is not always possible to determine if a wall is a bearing wall by looking at floor joists. So, before you plan on moving a wall ask a contractor or architectural engineer to determine its structural function.
If you discover a wall you want to remove is a bearing wall, it does not mean that it is immovable. You have several options. You can replace it with another wall nearby, calculated to safely take over from the old wall. You can also have a header installed that is a beam spanning the opening created by the removal of the bearing wall. This header is carefully designed based on mathematical formula and engineering standards to hold up the weight of the upper building. Its size and what it is made of will be determined by this formula and the esthetic requirements of the design. A wood header may be large and project down into the opening like a cross beam on a beamed ceiling. Replacing it with a metal I-beam or a high-tech laminated wood I-beam may mean less intrusion into the room. Long spans may require the rigidity and strength of a metal or laminated wood beam.
As you can imagine this entails extra time and expense. Removing walls is something that must be planned for early and you should be fully aware of the costs and design compromises that may be involved.
Outside Walls
As we mentioned you can consider all outside walls as bearing walls that must be dealt with in a similar fashion to interior bearing walls. However it is also important to know that when you cut an opening into an exterior wall to add a window or door, you are compromising the structural integrity of that wall. All outside windows and doorways are framed with smaller headers across their tops to support the roof. The rule of thumb in making structural changes is to assume that any change in the framework or roof structure of the house must be planned and executed by a professional.
