Standards and Procedures:
Locust Log Ladder Staircase
There are many ways to build a locust log staircase. The Pisgah Ranger District is moving to embrace and prioritize a particularly robust and sustainable option: the log ladder staircase. Tried and tested in the rainforest conditions of the Smoky Mountains, this method delivers an incredibly stable and versatile structure that effectively resists soil erosion even on the steepest slopes. Every part of this staircase is connected in one unified structure. The combined weight of the components, plus fill, results in a rock-solid set of steps that holds itself in place without the need for rebar or stakes. The presence of stringers on the side of the steps, in addition to holding the individual steps tightly in place, prevents fill washout and encourages users to stay in the center of the staircase. Overall, the log ladder method is the most sustainable and reliable method in most situations where a steep grade needs to be mitigated.
Historically, check steps have been a popular method of building log staircases in the Pisgah Ranger District. While check steps are a simple method of building stairs, they don’t tend to hold up well over time, especially in an area as rainy as the Pisgah. It is very easy to find examples of check steps that have been undercut or blown out, turning into high, unsightly obstructions that users avoid. This contributes to wide, braided trail and more resource damage as users go off trail to dodge these failed steps. While check steps can still be useful in certain situations (deeply gullied sections of trail), in most cases a log ladder staircase is far more reliable and a better investment of our precious black locust resources.
- Log Ladder Staircase: A Sustainable Solution
Building a log ladder staircase requires a few specialized items in addition to the normal array of trail work tools. Below is a list of the essential items.
- 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
- 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
- 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.
- Notch each step into the side rails using a chainsaw in addition to pinning with spikes. This takes a lot of the physical strain off of the spike and prevents shifting over time.
- Keep a 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 (this step is also the bottom of the box frame).
- Entrench the entire frame enough to eliminate gaps underneath. Crush rock around the entire frame.
- Steps should be level from side to side.
- Use miter joints and spikes to construct a solid box frame for the staircase. Stringers (sides of the box) should be level across.
- 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 rock armoring instead.
These procedures are intended to provide a helpful reference guide to building log ladder staircases, 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.
A. Building the Box Frame
1. Survey the site, come up with a plan
2. Cut locust to length
3. Lay out logs and determine best positioning. Take advantage of natural log contours in layout.
4. Check for level, adjust/excavate if necessary
5. Miter Cuts to join logs into a box frame
6. Drill and spike joints together
7. Dig joined logs into place
8. Pack with crush to stabilize
B. Installing Steps (“rungs”)
1. Determine Rise/Run and step spacing - using a line level can hep to estimate the number of rungs needed and the spacing between them.
2. Mark the first step, orienting it so the flattest side is up.
3. Notch step into both side rails so it fits tightly.
4. Check for level.
5. Drill and spike step from each side.
6. Pack firmly with crush.
C. Finish Work
1. Add/Tamp crush where needed.
2. Top landings with mineral soil.
3. Incorporate drainage above, perhaps integrating a log water bar into the staircase
4. Clean up and revegetate work area