Figure 1-4. Decay Caused by Steam Lines. (Steam lines close to wood
components may cause some deterioration of wood due to high
temperatures, and leaks in the lines may create moisture problems.)
in the performance of those members. When wood members extend outside the
wall, and particularly beyond the roof line, there is a high potential for decay
unless they are preservatively treated. If such members are strictly for esthetic
effect without serving a structural function, the building may not be endangered;
however. when structural support such as an arch base (Fig. 1-5) is outside the
building, any deterioration can have a major impact on the safety of the building.
Special attention should be given to exposed end grain of wood since water is
absorbed much faster in the grain direction than it is absorbed across the grain.
Proper flashing over the top and ends of wood members often gives good pro-
tection, but total enclosure of the end may accelerate decay by trapping water.
Also. ends of members supported on horizontal surfaces may be subject to ab-
sorbing water that stands on the surface. If these exposed members are near the
ground, lawn watering or backsplash from rain may cause additional wetting.
Any ground contact of wood is a major hazard unless the wood has been preser-