How to build a retaining wall with railroad ties
Retaining walls are commonly constructed as a remedy to convert unattractive, steep areas into usable, visually appealing, and safe areas on properties where a rough, or problematic slope has been unuseable.
From a realistic perspective, landscaping and maintaining excessively steep slopes can be unsafe and even impossible. Cutting grass on a steep slope is dangerous at the best of times. Perhaps erosion and soil movement has washed steep gullies, and the slope is now so rough it is virtually unusable, or in the extreme, even totally inaccessible.
Retaining walls can provide not only level areas, but a solution for unstable soil conditions and soil displacement caused by continual erosion of steep slopes. If excessive groundwater and surface runoff is a serious issue, a homeowner may be left with little but steep, mud-filled gullies partially covered with unsightly vegetation.
A well-built retaining wall can not only reduce problems with yard maintenance, but if designed carefully and well built, can significantly increase usable space, curb appeal and perceived market value of the property.
Used railway ties and matching switch ties of various lengths are timbers treated with creosote to prevent decay and rot when placed in contact with soil and moisture. Used railway ties, available at most landscaping and building supply outlets, are recycled materials .
Evaluate the site: Plan and design considerations
For any construction project, site requirements must be carefully evaluated.Ensure your new wall will meet those requirements by drawing a plan. Draw it to scale if possible, but a simple pencil sketch on squared paper will suffice.
On your plan, show the elevation, length, and other design features including proposed treatments for the ends of the wall. Note the location of any infrastructure and buried services, the lot line, and the distance from sidewalks or roadways. A simple drawing can prove to be very helpful in identifying potential problems, prevent mistakes, and is useful for accurately determining and confirming the quantity and type of materials required.
When planning, calculating the height of the wall is essential. Consider modifying the design, including a step, or a second wall if the proposed height is 6′ or greater. Check to see if there are any safety restrictions on the height of retaining wall in your jurisdiction. A perimeter fence may even be required at the top of the wall to meet municipal safety level-1s and by-laws.
To determine how high the wall must be, measurements must be taken on site.
On the high side of the slope, place a temporary picket with a line attached at ground level. Have a helper hold a suitably tall «try stick» vertically at the low end of the slope, and adjust the string to a level position. A line level hanging on the string is helpful to approximate where the future ground surface will meet the projected top of the wall. At the «try stick» location, mark and measure the distance from the string to the ground surface. Now you know approximately how high the wall must be.
If site and soil conditions are difficult, and if a wall is required to be over 8′ high, a more complex engineered solution may be required to ensure structural integrityand safety . Such megalithic structures require include a footing to support substantial weight.
Consider building an offset in the wall or adding a short buttress wall for extra strength and stability as reinforcement if soil conditions in the area are known to be unstable, if the wall is very long, or if the projected wall height is excessive.
Address potential drainage issues: If surface water up-slope is problematic, plan on providing drainage at the source if possible. Avoid draining water through the face of a retaining wall which causes stains and may cause structural damage.
Lay out the wall on site
Following your plan carefully, establish the exact configuration and layout of the wall prior to doing any excavation.
Clear the area of brush and refuse, and lay out the project carefully by outlining the footing area. Install a picket on each end of the wall and set up a string level on the line. Adjust the height to ensure it is level from one end to the other. Install pickets at intervals along the line to determine how much soil must be removed to establish a level base for the wall. The depth of soil that must be removed will be in part determined by soil conditions encountered on the site.
After outlining the trench with pickets, verify the physical distance required to lot lines. A minimum distance from from the wall to lot lines may be required in your jurisdiction.
Dig a Trench for the footer or base of the wall
Remove the sod and organic soft topsoil down to hard, firm sub-soil layer. Dig a trench twice as wide as the railway ties, and ensure the bottom of the trench is flat and level from from end to end. Allow room for the placement of a length of drainage pipe immediately behind and on the uphill side of the ties unless the soil encountered when excavating is gravel or coarse sand.
Establish the footing
If the wall is to be much higher than 3′, a footing may be required where soil conditions are wet, soft, or unstable. Install a minimum layer of 6″ of gravel compacted as hard as possible. If the on-site soils are gravel or hardpan, add only enough additional gravel to make the footing level and even. Pack any loose gravel or soil added with a gasoline-driven plate packer or manually tamp it smooth and level. Hint: Spray the gravel or sand with water to make packing easier and optimize compaction.
Set the first course of timbers in place
Lay out the position of the first course of timbers using a line and pickets. Set the first timbers in place, ensuring they are level and sit securely on the gravel pad. Add gravel as necessary and pack firmly if required. You may wish to drill holes in the timbers and drive steel reinforcing bars though the timbers into the undisturbed soil to ensure the timbers do not move out of line.
Add subsequent courses
Add the second layer of ties, ensuring the joints are staggered. Allow for placement of «deadmen » anchor ties. *Place deadmen anchors at right angles to the wall and ensure they are dug into, and buried on the uphill side of the wall. Drill holes and drive reinforcing rods to hold the second course and anchor ties in place.
If the wall is projected to be higher than 3′, backset the second and each subsequent course marginally (approximately an inch) for every foot of height. Doing so provides additional stability and strength.
*Remember that high walls are subject to far more lateral (side) pressure from soil movement. Add deadmen anchors on alternating courses, burying them and packing the soil around them as you go.
Install drainage tile
Install the weeping tile, or flexible drainage pipe on the uphill side of the first course. The bottom of the weeping tile or pipe should be at the same height as the bottom of the first course. Place the holes in the drainage tile facing down to prevent the eventual plugging up of the tile.
Route the ends of the drainage tile around the end of the wall so water can be discharged safely away from the wall.
Cover the drainage tile with free-draining gravel, and backfill the first two courses with gravel. Add native fill or imported fill as necessary to hold 12″ or more of gravel in the drainage area immediately adjacent to the wall to keep the drainage area free of mud, fine silt and washing soils when water is actively draining.
Add subsequent courses of ties
Add all necessary remaining courses of ties to achieve the height desired.
Ensure that all joints are staggered, and add extra deadmen anchors on alternating courses particularly if the wall is high and soil conditions on the slope are soft, friable, and unstable.
Trim the ends of the wall for a custom look: Be creative
Finish the ends of the retaining wall as desired. The ends of a retaining wall may be:
—Beveled appropriately matching the ends of all courses. Snap a chalk line down the end of the fence at a suitable angle, and bevel the ends using a chain saw
—Finished with a piece of suitable treated dimensioned timber or a trim board fastened to the squared, matched ends of the timbers.
—Terminated with a vertical post: Install vertical fence posts at the ends of the wall. Dig a hole 3′ deep and tamp a suitably sized timber post tightly in place. Fasten posts to the wall using long spikes and «Cap the post» by trimming it off decoratively. The post may be left taller than the fence for a sign, decoration, or as a «monkey post» to display large hanging baskets
—Decoratively ‘stepped’ : Each subsequent course of timbers is trimmed shorter than the one beneath it. This method is commonly used as a convenient display for potted plants or flowering bushes.
-Disguised: Plant bushes adjacent to the ends of the fence and Consider climbing ivy , decorative placement of natural rocks, or flowerbeds to provide an attractive visual focal point.
No matter which method or accessories you may use to finish your wall, simply taper and adjust the final height of the landscaped surfaces to suit.
Backfill the retaining Wall
Backfill the wall with convenient native material from landscaping surrounding areas if available, or import sufficient additional soil. Backfill the slope to within 4″ of the top of the wall. Place gravel against the wall for each layer, and add supporting layers of backfill. Pack the fill in «lifts» or layers firmly to ensure minimal soil subsidance over time and compact the soil tightly around deadmen timbers. Ensure the free-draining gravel is held against the wall to provide positive water drainage.
Add topsoil and level the filled area to suit
Add topsoil to within an inch or two of the top of the wall. Level out, rake, and seed the area, or place sod if desired. Remember to over-seed the adjacent lawn area with the same species of grass seed to ensure a uniform transition to the existing lawn area.
Landscape and fill the base of the wall
Remove all extra piles of dirt, gravel, and other detritus from the site. Landscape the downhill side of the wall. Add extra soil as extra support for the bottom course. Add topsoil, rake, roll and seed as necessary. Disguise the drainage tile discharge locations suitably with decorative rocks or selectively planted bushes.
If the wall is high, the apparent height can be reduced with the addition of rocks and soil. Plant bushes or decorative plants to increase aesthetic values.
Add a safety fence if necessary
Install a safety fence if the wall is high. A perimeter fence may be required by municipal by-law in your jurisdiction. Falls even from a height of less than 6′ can be fatal.
If construction of an appropriate fence is to be delayed, provide a temporary barrier at the top of the wall until a suitable fence is constructed.