Alpine

41 Charlie's advice on situations to watch out for in the field: • No purlins, or no lateral bracing under field applied piggybacks - You will need a braced system to keep the flat top chords of the hip trusses from bending out of plane (usually purlins, as shown in blue), plus some kind of bracing for those purlins (in red). Engineering firms familiar with wood and/or steel truss systems, such as the Alpine Structural Consultants, can assist in designing the right system. • Missing web bracing – If the truss drawing shows a web brace (CLB, T-Brace, L-Brace, Scab brace) and hasn't been applied, it needs to be applied! Refer to the truss drawing for brace size and connection information. • No decking under a valley set – Remember that it is important to brace the top chords of the trusses under a valley set. Apply sheathing under the valley set, and attach the valleys well to that sheathing. • Leftover girders or other trusses on the ground – If you have set all the trusses on the roof but there are still trusses on the ground, double check the truss placement plan, and call the truss manufacturer. You may have missed an extra girder ply, or they may have made a mistake. Either way, it's important to be confident that you have the roof system in place properly! • Deflecting girders, or incorrect fastening of girder/beam plies – Multiple ply girders and beams MUST be fastened together BEFORE you put any loads on them!!! The truss drawing will provide instructions for the nail type you should use and the proper nail spacing for each member (Top chords, bottom chords, and webs). Also, if a bearing block is specified on any truss, be sure to install it! • Trusses installed backwards or upside down – For any truss that could possibly be installed upside down, or backwards, take time to look at the truss drawings and find out how it was designed to be installed. If you have installed a truss backwards or upside down, either re-install it properly, or call the truss manufacturer ASAP to work together to resolve the problem. • Lumber grade markings – Trusses are built with special engineered lumber grades, and the wood is stamped with that grade marking. If you don't see those stamps on the wood, double check to see that it was built using the lumber grades and sizes specified on your engineered truss designs. • Missing plates, broken or cracked web members – Sometimes during handling a plate can fall off, or a web will crack, or a sub- contractor can cut through a web to install electrical, etc. You should never cut a truss without consulting with the truss manufacturer. If you see any of these situations, contact your truss manufacturer for assistance in resolving these problems. Trusses are engineered to perform under designed loads, but they assume all the webs and chords are in good shape. Damage to a web or chord can require a repair (many times a simple repair for such conditions), in order for the roof to be structurally sound.

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