![]() In other areas, a single holdown on each end of the wall line should be sufficient. In high-seismic and high-wind areas, holdowns on both ends of each panel are still necessary. This is not likely given the depth of the header. Now the overturning forces in the narrow wall panel must bend the header for the panel to rotate and overturn. However, if the header is run all the way into each corner, with double king studs on each end and double trimmers on each side of the window or door opening, structural panels running plate to plate on these narrow walls can tie the wall and header together as one. When the header ends at the edge of the window or door opening in the case of garage doors, the overturning forces need only to bend the double top plate to rotate the narrow braced panel beside the opening. But headers also can provide a great deal of resistance to these forces. Holdown anchors resist overturning forces by attaching the framing to the foundation. Then you end up with very high overturning forces. Studies have shown that narrow wall panels provide little racking resistance unless all the edges are nailed at a very close nailing schedule. If you make the walls stiff enough to reduce the racking potential, you end up with another problem called overturning. Proper bracing resists this racking process. So if the building can't slide, the next thing lateral forces do is rack the walls. This sliding force, called base shear, is resisted by the anchor bolts. The first thing to understand is that lateral forces on a building create loads that cause the building to want to slide off its foundation. RELATED: Do Advanced Framing Techniques Benefit Remodelers? Want more? Check out our story about advanced framing. Let's look at how to deal with walls that are only 24 inches wide or even 16 inches wide. However, there still are designs that place walls less than 32 inches wide beside large openings. The code has an alternate bracing provision that allows you to reduce those 4-foot braced wall panels to 32 inches if you do certain things with your nailing pattern and anchor these narrow wall sections in a prescribed manner. Testing and experience have demonstrated that narrow wall panels do not provide the lateral resistance needed in many cases to resist the lateral loads imposed on a structure. You end up with narrow walls beside large expanses of glass. When additions are designed, the walls often are not wide enough to allow for 8 feet of solid braced panels as well as the windows the homeowner wants. It would be ideal if designers provided these panels at each corner in their plans, but it just does not happen. The code says you should have a 4-foot-wide braced wall panel on each corner of the structure and every 25 feet down the length of the wall. But you must remember to provide solid wall space on either side of these large areas of glass to provide lateral stability for the structure against wind and seismic forces. Putting windows from corner to corner on an addition is not unusual. Among the key things are more stringent bracing requirements for walls. With the advent of the new international building codes come changes with which all of us have to deal. Bracing narrow walls beside large openings Let's look at some common framing problems and how you can fix or avoid them. While terminology and t echniques vary from region to region, certain framing problems don't. Over the past 25 years as a builder, building inspector and lumber industry representative, I've inspected a great deal of framing all over the country.
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