Trails in Wet Areas (continued)

Subsurface Puncheon

Subsurface puncheon involves construction with the mud sill, stringers, and decking under the surface. This design depends on continual water saturation for preservation (Figure 52). Moisture, air, and wood are needed before wood can rot. Remove any one of these and rot won't occur. A good rule for reducing rot is to keep the structure continually dry or continually wet. Totally saturated wood will not rot because no air is present. Cover the surface between the curb logs with a layer of gravel, wood chips, or soil to help keep everything wet.

Figure 52—Subsurface puncheon with covered tread surfacing.

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