Unless you live on the prairies or are situated on completely flat ground your yard will have a pitch to it. Sometimes the slope of a property is very steep, too acute for trying to manage a lawnmower. Although you can terrace the lot the most effective way to claim flat ground, or a succession of flat areas is by using either one or more retaining walls.
Damming up earth goes back to the dawn of man when, for safety, communities were built in the higher country. In Southeast Asia the farmers still use an ingenious system of retaining walls which not only hold up earth but hold water for planting rice. In many parts of Canada we have no choice but to build on sloping ground and many of our roads are supported by a series of metal or concrete retaining walls.
A retaining wall system can literally make a sloping surface flat. If the rise is under 6 or 7 feet high it can usually be accomplished with one wall. Despite the material from which the wall is made, the dirt in the area behind the intended wall is cleared back to make room for the work to done. This area is then filled with gravel so that water can easily make its way to the bottom and out through a drainage system. This prevents back-pressure from the ground above which can cause the earth to move against the top of the wall and push the wall forward.
For higher levels a second and third wall is built 2 to 3 feet back from top level the first wall.
The traditional retaining walls were made from timber stacked in interlocking patterns in much the same way that a log cabin is made. Over time these structures would decay but many embankment held its shape because the roots of the vegetation and hard-packed earth retained the shape. Creosote railroad ties became the norm and worked very well because of the preservative nature of the chemicals in creosote. They were cheap and readily accessible from either rail yards or landscaping supply centers. Today, landscapers frown on using ties because they were unsightly and damaging to vegetation and the environment as a whole.
New standards for wood preservatives have seen the exit of dangerous chemicals so now it is not dangerous to the ecology and your plants. These pieces can be as large as railroad ties, or 4 X 4 pieces. They are relatively inexpensive compared to other products and can be easily put together with spikes or bolts. Because the preservative this wood will last a long time but is limited to straight lines. Wood also can look unsightly after time.
Gabion Wall Systems
This wall type is rally a series of square cages made from galvanized steel fencing which are filled with rocks. The draining properties with gabion wall systems are great but they can shift over time as the stell stretches. Gabion walls are usually used for commercial applications.
Reinforced concrete with the proper drainage is used in commercial areas to great success. For home use it is very expensive compared to other materials and after time concrete takes on a dirty appearance. Mold and mildew like to get started in the porous surfaces.
Stacking flat stone in mortar is a time-honored way of making a retaining wall. The top is capped off by a ridge of cement and finished with a smooth, bull-nose edge. This wall looks very striking and adds a country estate-look to the yard. However, it is very labor-intensive work that means that the bill will be high. In addition, the freeze-thaw cycle of the is not easy on the walls as the stones will move and, eventually, the cap will begin to crack in places.
Block Retaining Walls
For any appreciable size of retaining wall cement block leads the way. Because of its interlocking abilities block can be assembled easily by a novice and the individual blocks can adjust to the expansion and contraction of water both in the ground behind and in between the stones.
As with building any retaining wall there must be a good base of compacted gravel. For good drainage a line of 4 perforated pipe is placed on the back-side of the wall and just below the level of the first row of block. It is crucial that the first row of block is level because it will effect the ones coming after. The second row is then placed in an alternating pattern much like brick on a wall. Special edging prevent the block from slipping forward so as you go higher the wall stays straight.
Before the gravel backfill is put in it is always a good idea to lay down in a layer of earth fabric against the earth embankment. This will prevent dirt from getting into the gravel over time and plugging up the drainage. It will also stop roots from pushing into the gravel that could also compromise the gravel drainage.
For a perfect retaining wall contact a landscaping designer A group of dedicated professionals can do the work in a fraction of the time of a home-built wall and without the mess.Posted by: TrustedPros