Alpine

FLOOR TRUSSES Typical Bearing / Heel Conditions for Typical Bearing / Heel Conditions for Common complaints about noise through ceilings in floor trusses include walking, moving furniture, and dropping objects, all of which are considered impact sounds. When addressing noise in floor systems, the Impact Insulation Class (IIC) rating is often the most critical value to consider. In general, IIC values for flooring are similar to their Sound Transmission Class (STS) values, so satisfying the code requirement for one will typically work for the other, if not come close. A floor/ceiling's ability to limit sound transmission is not highly dependent on the type of joist or truss to be used, but rather the types of insulation, sheathing, flooring, and subflooring. Most basic floor/ceiling construction materials like gypsum board and hard surface flooring don't provide much IIC value. The best methods for reducing impact noise, besides substantially increasing the floor systems mass, is to use specialized acoustic products such as resilient channels and special acoustic underlayment's, as identified in Figure-1. Many of these measures are effective at reducing only certain types of noise and work in combination with the other measures to create a complete soundproofing system. Batt insulation, for example, is effective for absorbing airborne sounds, but does little or no good against structural/impact noise. While carpeting with a fairly thick layer of padding beneath it is excellent at reducing impact noise, it is not effective against airborne noise. For additional information regarding Sound Transmission in Wood Floor and Roof Trusses, refer to SBCA report: . SRR No. 1601-03 Bracing is extremely IMPORTANT!! Every truss system needs adequate bracing. The purpose of most bracing is to ensure that the trusses and truss members remain straight and do not bow out of their plane. Inadequate, improper or incorrectly installed bracing can lead to collapses, failures and serious accidents. An engineered bracing system will avoid these pitfalls and ensure the structural integrity of the truss system. Trusses need to be braced during installation, which is called temporary bracing and they need permanent bracing which will remain installed for the life of the roof system. Temporary Bracing Guidelines: For metal plate connected wood truss systems, refer to BCSI-B7 for proper installation bracing guidelines. The provider of this document, nor any of its divisions or companies, does not warrant the recommendations and information contained herein as proper under all conditions and expressly disclaims any responsibility for damages arising from the use, application, or reliance on the recommendations contained herein. Sound Transmission through Floor Trusses 7 Powerful CAD-based design software from Alpine generates traditional plan view layouts, and 3-D graphics that give an accurate picture of a structure from virtually any perspective by showing every component in place. Work confidently with the industry's best fully integrated design solution. Our IntelliVIEW software reduces both designer time and aggravation, giving you more peace of mind with fewer mouse clicks. Layout, Design and Engineering Software Figure-1

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