Figure 7-7. - Required caulking around window frames.
Bowing of overstressed compression members
Evident separation of joints caused by shrinkage
Development of splits along lines of bolts
Development of splits in ends of web members and chord splices
Pronounced sagging of trusses
Normally, if an actual failure has occurred in a chord member, that member should be replaced. To do this, shore the truss at the panel points along the bottom chord and the remove the damaged member. Using the damaged member as a template, you can fabricate and install the new member. The replacements should be of the same material as the truss and of the same moisture content, if possible. To replace any truss member is usually a costly operation; unless the building is for permanent use, the member should be repaired or augmented rather than replaced.
Checking and splitting are normal reactions in most timber as it dries out. The checking and splitting are more pronounced when unseasoned lumber is used. If the split passes through the bolt holes and continues beyond into the member, it will require attention. The recommended remedy for splitting and checking is the installation of STITCH BOLTS. Figure 7-8 shows the use of stitch bolts in repairing scabs in which end splits have developed; also shown is stitch bolt repair to wood columns in which splitting and deep checking along the grain have occurred. The bolts used for this purpose are 1/2-inch bolts, threaded on both ends. To repair scabs, drill 1/2-inch holes 2 or 4 inches from the end of the split member and perpendicular to the axis of the member. The bolt is then inserted, a 2-inch square-cut washer placed at each end, and the nuts tightened. Installing the stitch bolts before tightening the bolted connection is advisable.
Failure to inspect, recognize, and correct minor defects and deterioration in its earliest stages is probably the greatest cause of premature roof failure. All roofing materials deteriorate on exposure to weather, and the rate of deterioration is affected largely by the kind of material involved and the conditions of exposure.
In inspecting structures, you will probably inspect different types of roofing, such as built-up, asphalt-shingle, wood, metal, tile, and slate. No attempt is made here to cover in detail the many types of roofing materials and their component accessories produced by numerous manufacturers, but rather to discuss, in general terms, the inspection and preventive maintenance procedures peculiar to built-up and metal roofing.Continue Reading