Build Retaining Walls with Railroad Ties
It's bright and sunny outside, and time to cut the grass again,
You cut the side yard first, perfectly and evenly with the mower, and then look at the long grass in the back yard with trepidation. It is lawn that is far too steep and the soil is precariously eroded from endless water runoff. It is impossible to cut the grass safely with a lawnmower, so you haul out the weed whacker and start giving the treacherous area a tedious, crude haircut one more time.
You know you need a retaining wall but have procrastinated in building one, for the cost of manufactured, interlocking concrete stones commonly used to construct retaining walls is too high for your budget.. How can you build an inexpensive retaining wall?
The answer may be to build a retaining wall with railroad ties.
Where can you get railway ties?
Railroad ties, also called cross ties, are creosoted or chemically treated timbers that have been historically used to lay railway track all the way across North America. The treated wood ties resist decay for years but are eventually replaced as a matter of safety. Replacement may be with new timbers or the increasingly common concrete rail bedding ties. The replacement program has left millions of used and unused railway ties, switch timbers, and other large creosoted timbers available for other purposes including landscaping.
To find a source of railway ties, ask at your local building supply, landscapers, building contractors, or your nearest rail yard.
* Incidentally, do NOT feel free to help yourself to piles of ties you may happen to see along the railway tracks. Trespassing on railway property is both illegal and dangerous.
Buy railway ties from reputable contractors that often have contracts to legally remove hundreds, even thousands of ties at once, and do stockpile them for sale. Expect to pay higher prices for better quality timbers.
Choosing Ties
Choose ties that are not rotten, have no major splits in them, and preferably, are all the same size for convenience in construction. Some ties will be deteriorated, others will seem to be as good as new. Choose well.
*NOTE: Caution Required!
*Creosoted timber is very heavy. Railway ties usually weigh well over a hundred pounds apiece. Ensure you have adequate help to carry, load, or move railway ties safely.
*DO wear leather gloves and keep arms and legs covered when working with creosoted wood; slivers of treated or creosoted wood can cause infection and wounds with creosote in them heal very slowly. If you do get wounded with a sharp fragment of creosoted wood, seek medical advice!
Tools and Supplies You will Need
You will need railway ties, pickets, a supply of crushed stone, some coarse gravel, a length of 4" perforated weeping tile, measuring tape, sledge hammer, carpenter's line or string, sections of " steel reinforcing bar or the equivalent, shovel, pick axe, carpenter's line level, a plumb bob, a power drill and appropriate drill bits, a hacksaw, grinder or power cutoff saw with a blade for cutting steel, and a chain saw, preferably equipped with a carbide-tipped chain if available. Creosoted timbers, especially dirty used ones, dull saw chains quickly. Rent a vibrating plate packer if possible to compact the backfilling.
Prepare to Build the Retaining Wall
Start at the lowest area and stake the layout for the wall using pickets. If the design is more complex, do draw a plan first.
Remove the top layer of grass and organic soil and level the trench. A retaining wall is ideally best kept level from one end to the other, so DO excavate the base to level. Excavate the high end down if at all possible. Fill the lower level as necessary ONLY as a last resort. Pack or tamp any fill material adequately if used at all. Make sure the trench and base is wide enough to include a drainage tile if wet conditions are present.
Address and Solve Drainage issues:
DO remember there can be serious drainage issues with retaining walls.
Failure to provide drainage may result in washout, serious instability, and ultimately, even total failure and collapse of the wall. If soil conditions are very wet, installing a perforated weeping tile on the uphill side of the retaining wall will allow the water to escape. To ensure free drainage down the full height of the wall, backfill behind each course of ties with coarse gravel so water will percolate down to the weeping tile.
If surface water runoff is a serious issue, consider installing a French drain on the upper end of the drainage area to provide surface drainage. See "How to build a French Drain".
Structural, Stability, and Design Issues and Solutions:
If the wall is long, and the site slopes sideways and can not ideally be made level because of bedrock or other considerations, consider modifying the design to include dividing or even off-setting a portion of the wall to take advantage of the unique features of the site. For example, level individual sections, even at different elevations, and consider installing a convenient access stairwell to take advantage of the division.
Remember also that if the wall is long and high, to be stable, it may require installing dead men' timbers at right angles in alternating rows to enhance structural stability. That process is accomplished by laying a timber at right angles into the wall on alternating courses, with the timber extending and buried in stable soil uphill.
Deadmen timbers should be placed every eight feet on alternate courses as a minimum, if the wall is very long. Install galvanized "T" plates, nailing them both securely to the deadmen timbers and to the adjacent face timbers to prevent the deadmen timbers from pulling out and becoming ineffective as the wall continues to move out.
Alternatives to improve stability include incorporating one or more complete, short right-angle, sections of wall into the layout as aesthetically appealing abutments for stability, planting vertical support members in front of the wall similar to installing a fence post, or using galvanized "cable deadmen" tied to 4' pieces of timber trenched and buried parallel to the wall in solid, stable, undisturbed soil.
Determining and Minimizing Wall Height
Excessive height of retaining walls can be a safety issue. Six feet is generally considered to be the maximum, but DO verify code requirements or limitations on the height of retaining walls in your jurisdiction, regardless of building materials used, otherwise you may also end up installing guard rails or security fencing for safety.
To avoid building excessively high walls, consider controlling individual wall heights by planned terracing or stepping the timber walls back toward higher ground. Alternatively, consider using low, successive retaining walls, with wide terraces and access steps for safety considerations, better use of the area, and the opportunity for extra visual appeal terracing can provide.
Three 2' ' high retaining walls with an appropriately landscaped terrace with flower beds and bushes between them may ultimately be far more attractive than one blunt 6' high wall right at the street.
Working carefully, let us proceed with the construction of the timber wall.
Install a 4-6" layer of crushed stone to provide stability and avoid excessive settling of the finished wall. String a carpenter's line to keep the wall straight, or curve and angle as desired
Install the first row of ties on the bed of crushed rock and carefully level it.
Cut 2' sections of construction steel reinforcing bar or other suitable steel bar. Drill holes through the ties at both ends, and using the sledge hammer, drive the steel bars into the ground to hold the ties in place securely. The first course is now complete.
Install the perforated weeping tile level with the bottom of the timber, on the UPHILL side of the timber, placing the holes facing DOWN, and cover it with crushed rock.
Backfill to the top of the first row with coarse gravel immediately behind the timber.
Determine the final height of the wall after the first layer is installed. That will determine how many more courses of timbers you require, keeping in mind that a retaining wall should not be more than 6' high for safety considerations. Establish the grade required to the top of the wall using a transit level, a line level, or sighting a 4' carpenter's level. Mark the top of the finished grade on a picket or stake driven into the ground at the outside of the first row.
Proceed with the second course, alternating the joints as is done in brick or block work. Remember the old masonry rule "one over two, two over one" so there are never two joints vertically adjacent.
Proceed with subsequent courses of timbers, fastening each in place with reinforcing steel rod driven into the preceding layer.
Ideally, fill, wet down, and compact the gravel and dirt behind each course of timbers as you go for stability and less settling in the future. Use a motor-driven vibrating plate packer if one is available.
Complete and secure the top course, pegging it securely with reinforcing rod, or consider lag-bolting the last course in place with long galvanized lag bolts if available.
Backfill immediately behind the timbers with coarse gravel, establish the final grade as required, compacting it well, and top with soil as required.
Check and correct the grade, filling as necessary. Rake and pack with a water-filled lawn roller.
Provide lawn seeding or sod and landscape as desired.
Now that your retaining wall is complete, your yard will be much more useable, it will be much easier to maintain, and you can breathe easier cutting the grass with the lawn mower. The best part is, building a retaining wall with railroad ties did not break the bank.
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