Standards and Procedures:
Locust Log Box Steps
There are many ways to build a locust log staircase. Generally speaking, the most sustainable and materials-efficient method for building log steps in the Pisgah Ranger District is to construct a unified log ladder staircase. However, there are some contexts where a log ladder staircase will not easily fit the terrain, such as mitigating a spot where the trail makes a sheer climb up a rock face or if erosion has been so severe that there is a huge drop off. In these cases, a ladder staircase would end up effectively “floating” in the middle and would need extensive cribbing to shore up the outside and retain fill. An easier way to do this is to build box steps, which incorporate the cribbing into the step design and can effectively scale a sheer climb while retaining fill.
Box steps are very sustainable, and aren’t overly complicated to build, but they do require more material compared to log ladder staircases. Given the limited amounts of black locust trees in the district, building box steps should be undertaken only where the design is justified by the specific terrain.
Key Points:
- Log Box Steps
A set of box steps constructed in Great Smoky Mountains National Park. This spot had a problem where there was a steep climb over the tree roots. Thanks to the stacked cribbing of the box step design, these steps are able to ascend to the top of the climb while retaining fill. A log ladder staircase would have been vulnerable to fill washing out on the sides. Note the bottom step is firmly embedded in the ground.
Log Box Steps - Recommended Tools and Equipment
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Below is a list of the essential items for building log box steps.
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- Chainsaw with a sharp chain
- Extra sharpened chain recommended
- Draw knives for peeling bark
- Power drill capable of drilling into locust wood (portable battery powered or gas powered are both fine, just make sure they can handle locust wood and bring extra batteries/fuel)
- ⅜” auger drill bit
- 8,” 10,” or 12” long ⅜” landscape spikes (depending on size of locust. Good to have a mix)
- All appropriate PPE for chainsaw work
- Extra ear protection, as you will need a partner close by to hold logs in place during some cuts.
- Single-jack sledge hammers
- Level
- Tape Measure
- Lumber crayon, marker, etc to mark measurements on locust
- Assorted digging tools (pick, pulaski, etc)
- Mini/prospector’s pick, rapid digger, etc. useful for digging in tight areas
- Buckets or canvas rock bags for transporting gravel
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Locust Log Box Steps: General Standards
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- Install staircases in areas where the grade exceeds 12-15%, or where grade otherwise causes erosion problems.
- Drill pilot holes and pin all pieces of the staircase together with 8", 10", or 12" long ⅜" landscape spikes.
- Prevent undercutting - the top of each step needs to be level with the bottom of the step above it to hold fill. This should create a level landing from front to back with no gap underneath the above step. Take the extra time to get this part right, as it is key to a sustainable staircase.
- Individual steps should be no higher than 6-8”. Any higher and they become uncomfortable, leading to users avoiding them and causing trail braids.
- Fill steps with crushed rock or imported gravel, not soil. Pack the rock firmly with hammers. Top with a layer of mineral soil.
- Keep a consistent tread length (or “run”) of 10-12” when possible. Step run length will vary depending on how steep the slope is, and on very steep slopes you may need to resort to shorter runs. The goal is to keep steps as comfortable as possible so people will use them.
- Bury the bottom step to stabilize the entire staircase.
- Steps should be level from side to side.
- Use miter joints and spikes to construct each box step. Stringers (sides of the box step) should be level across.
- Spike each box step on to the step beneath it.
- Incorporate drainage just above the staircase.
- Be mindful of mixed use trails. On trails with heavy mountain bike use, steps may not be the best option if bikers would rather ride around them. Keep steps to a shorter height, or choose a method like Appalachian rock armoring instead.
Construction Procedures
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These procedures are intended to provide a helpful reference guide to building log box steps, ensuring that you cover the essentials. If you are new to building this structure, it is best to learn hands-on from an experienced trail builder.
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A. Survey the Site
1. Observe grade, determine if box steps are the best option
2. Use line level to estimate number of steps and material need
B. Building the Base Step1. Layout logs on site, determine best orientation
2. Measure/Cut locust to length
3. Make miter cuts to join logs at right angles
4. Drill/Spike joints, creating a “U” shaped box
5. Bury step, leaving a bit exposed
6. Check for level, adjust/excavate if necessary
7. Pack with crush to stabilize
C. Build/Install Subsequent Steps1. Measure/Cut locust to length
2. Miter cuts
3. Drill/Spike joints
4. Lay box on top of below step
5. Measure for consistent tread length
6. Spike in place
7. Pack with crush
8. Repeat
C. Finish Work1. Add/Tamp crush where needed
2. Top Landings with mineral soil
3. Incorporate drainage above
4. Revegetate work area
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