Retaining walls - what are and how to create them?
Retaining walls - the main tool for working with complex terrain on the site. With their help, they not only create terraces or play with planes and alignment, but also emphasize the beauty of the landscape of rockeries and rock gardens, a change in height, the style of the garden, its character. Retaining walls allow you to play with raised and lowered areas, hidden areas and green rooms. Modern and eco-friendly dry walls or more solid and complex structures help to turn the shortcomings of the garden into its main advantages.
What are retaining walls for?
Perfectly flat areas are a rarity. Flat, not requiring any global effort, allocated specifically for gardens where a large area should be occupied by a garden, standard summer cottages from an absolute norm have become far from the most fashionable and promising option. And the situations when, in order to achieve this past imposed by stereotypes, the ideal is specifically leveled the entire area of the garden, it becomes less and less. But such projects in which an even or almost even relief are additionally changed, creating differences and levels, on the contrary, are becoming more.
What used to be considered a challenge and a challenge only for professionals, today is increasingly called a blessing. Indeed, an initially interesting relief is not only a chance to create a unique garden that is not like any other garden, but also a great way to “prevent” it from boredom, monotony and disharmony in its design. Difficulties or differences in the relief of the site turn a simple landscape into an interesting one, creating a variety both in terms of landscaping and the future atmosphere of the garden.
Tools for creating and strengthening elevations allow working with complex relief areas and the relief as a whole. And the main ones are retaining walls. With small changes in the relief, gentle slopes or slopes with dense, stable soil, they work with the help of reinforcing landscaping, special soil protectors and shrubs. But with steep slopes, cliffs, light soil, large ledges and elevations greater than 50 cm, you can only work with retaining walls. They simply have no alternatives where plants cannot hold back the shedding of soil or cope with its mass.
Retaining walls - the only tool for creating permanent objects located below or above the "central" level of the garden - the horizon. These are structures or structures that counteract lateral pressure of the soil and keep the soil from slipping and strengthen slopes, slopes, depressions and bulges.
From the point of view of functionality, absolutely any structure can be attributed to retaining walls, the main task of which is to strengthen the slope, create terraces or prevent shedding and destruction of the soil.
All retaining walls are simultaneously functional and decorative objects. From the point of view of landscape design and aesthetics, they belong to the number of vertical objects and structural elements. They divide the plots into zones, mask what you want to hide, create a background, bring order and harmony.
In recent years, the decorative role of retaining walls has become dominant and they are increasingly used only for an aesthetic purpose without a visible practical role. But they do not lose their status as the only tool for working with ravines, slopes, slopes and other elevations.
Using retaining walls in garden design
Retaining walls must simultaneously solve two problems - decorative and practical. The functions of soil retention, strengthening the slope, slope and cliff should be combined with emphasizing, clearly playing out the beauty and nature of the difference in heights and levels.
Retaining walls in landscape design use:
- to create terraces in a multi-level garden, divided into flat terraces;
- creating smooth spaces and zones in areas with complex terrain;
- imitations of complex and mountainous landscapes;
- separation of functional zones and framing sites;
- “Conservation” of complex natural relief;
- additions or replacements of rocky gardens;
- framing flower beds and creating multi-level and vertical flower beds;
- additions to reservoirs and objects of small architecture (including replacement of walls at arbors, pavilions or pergolas).
Depending on the role, retaining walls are divided into supporting (functional) or purely aesthetic.
Functional features of retaining walls
Supporting, protecting, emphasizing slopes and changes in heights - a task that is solved simply, to say so would be a big mistake. Reliability, durability, resistance to erosion and destruction are the main characteristics of any of the selected methods of playing with elevation differences, which you definitely need to think about when planning and arranging.
When choosing solutions for securing slopes and playing with terrain, practical characteristics always remain the main ones. Indeed, reliability and functionality in dealing with elevation differences are more important than any aesthetic visual tasks.
The functional purpose and type of retaining walls are determined after analysis of the following key factors:
- angle or degree of slope of the relief;
- ledge height or difference between relief levels;
- soil type, its “lightness”, friability, water and air permeability, tendency to erosion;
- composition and structure of soil layers of the maintained level;
- the area of the plot to be supported and the length of the retaining wall;
- location and type of propped level.
The durability, stability and bonding density of materials that will hold the slopes and ledges should be the higher, the higher and more difficult the indicators for all of the above parameters. The more difficult the relief and the site, the more durable the retaining walls should be.
Steep slopes are propped up not just by ordinary walls, but by structures made of very heavy natural stone or its artificial alternative with a foundation foundation powerful enough for the task. The higher the elevation and the steeper the slope, the greater the risk of errors. Steep slopes and cliffs are best instructed to strengthen professionals or at least get advice on the construction of retaining structures on them.
Aesthetic features of retaining walls
Not only practical nuances need to be considered when arranging retaining walls. Indeed, the following factors are also important in choosing a strategy and method of protecting slopes and drops:
- house architecture;
- dominant materials on site;
- existing or planned garden design elements;
- budget and features;
- garden landscaping strategy;
- regular or landscape type of garden;
- selected style of design.
When choosing materials for creating retaining walls, budget issues are one of the most important. For the construction of such structures, the most affordable, inexpensive options are always chosen.
For dry walls, you can use special bedding stones for dry masonry, stones for hydraulic structures, talus stones, boulder and other natural stones, and you can use the remains of building materials, used materials (concrete blocks, silicate brick, concrete pipes, etc.). ) or garbage and culling from quarries.
Brick and old brick are used for sandy, rocky and very light soils. The main criterion for the selection of materials for the retaining wall is durability and resistance to destruction under the influence of any weather factors.
Typically, the location, size and type of retaining wall "dictates" the relief itself. But when artificially simulating elevation differences and emphasizing the characteristics of the site profile, it is always worth remembering several principles for its arrangement:
- the structure should fit into the site as a whole and the specific zone in compliance with the harmony of mass, contours, lines, proportions and textures, without overtightening the landscape, but without getting lost in it;
- retaining walls, if possible, always oriented to the sunny side;
- the height of the retaining wall must correspond not only to a given level of elevation or the desired overlap of the zone, but also to the main architectural and structural objects on the site.
Types of retaining walls
In terms of differences in the nature and strategy of creating retaining walls, they are divided into conditionally natural defense and architectural solutions.
Natural support walls - functional structures that create an illusion as close to nature as possible, imitate natural protective elements. Such retaining walls are created from raw and roughly processed stone. And they mainly use natural materials and concreteless construction options.
Architectural delimiters and retaining structures - decisions are emphasized man-made and as expressive as possible in structure, form and style. Most often, these are structures that appeal to classical architecture or use artificial materials and concrete structures.
For ease of orientation in a variety of retaining structures, all walls are conditionally divided into drynot involving bonding with cement mixtures, and monolithic. But in practice, the types of walls are much larger. The following options belong to the main types of retaining walls.
Dry retaining walls
Dry retaining walls are structures that perform the task through the proper use of the mass of stones or blocks. They are made under a slight slope towards the slope of the wall of stacked on top of each other slabs, stones or blocks.
Dry walls can be built from shale stone, boulders, rubble stone, and even clinker bricks. Most often they use sandstone, limestone and dolomite. But to save money and where there are problems with access to quarries, you can use artificial stone and concrete blocks for this method of masonry. In the choice of materials, it is worth observing the principle of repeating or creating common connections with paths, a terrace, a house and water bodies.
This option retaining wall is an absolute favorite of modern landscape design. They change over time and in a peculiar way evolve, are environmentally friendly, resistant to small changes in topography, and are most reliable. Due to the lack of a one-piece structure, they are much more efficient and perform the same functions as walls fastened with concrete. But dry retaining walls are not an alien "unshakable" design and fit perfectly into the biological environment of the garden.
They allow water and air to pass through, allow plants to grow freely, and provide shelter for animals and beneficial insects. Despite the current misconception, they are appropriate not only in landscape style, because the nature of the wall can be made regular (we are talking about style).
Gabions or frame retaining walls
Gabions or frame retaining walls are an increasingly popular option for simple slope reinforcement. Single-layer or multi-layer gabions are blocks or boxes of metal mesh and other materials, filled with gravel, cobblestones, rubble, construction waste, used materials and have a huge weight that can hold any slope.
Gabions are small and large, they are simply installed on a prepared drainage pillow, "building" a wall of blocks.
Concrete walls are an architectural element that immediately evokes associations with European parks and classic landscaping techniques. They play with special colors when painting and decorating with plants, combine perfectly with climbing crops, open up many design possibilities and are considered an inexpensive form of retaining structures.
But any miscalculation in the construction, foundation, design slope should be considered irreversible. Concrete structures cannot adapt to changing the garden; they are little responsive to changes, prone to destruction, and require special care in manufacturing. It is better to entrust their construction to professionals, deciding on their own to break up such a retaining wall only with sufficient experience and skills.
Retaining walls for combined masonry
The retaining walls of the combined masonry are created according to the principle of dry walls, but with the fastening of individual elements of the masonry with concrete mortar to increase their stability.
Huge tree trunks and log cabins are rarely used as a retaining wall, and mostly only those who have free access to wood. If powerful trunks remained after cutting old plants, then after cleaning them from branches and cutting into equal parts, they are used to create retaining walls.
The construction comes down to creating a pillow from drainage materials and installing tree trunks in a flat wall at an angle to the side of the slope with a protective layer of gravel between the soil and the log houses themselves. They fasten such walls with special pegs made of hard wood.
For high retaining walls and steep slopes, this option is not suitable, but if you need a wall of small height, this design will do its job perfectly. A separate type of this type of retaining walls is considered to be masonry - the use of interwoven twigs of willow or other similar plants to strengthen the upper soil layer.
Sod retaining walls
Walls of turf - an original version of retaining structures, which is similar to dry walls according to the method of construction. Only instead of stones and their alternatives use the old turf cut into identical rectangles. Usually this option of retaining walls is built by those who replace or clean old large lawns.
Grass growing along the edges and the density of the turf allow the grass wall to perform retention functions for not too large slopes and completely replace the low retaining walls.
Difficulties and rules for creating support walls
In creating support walls, trusting the hands of specialists in their field has always been and remains the most reliable option. It is believed that retaining walls up to 75 cm high are safe for self-construction. The more complex the structure, the higher the risk of errors and wall destruction over time.
Any projects that include a retaining wall height of more than 1 m, with the creation of support pillars, expansion joints, difficult to drain soil, the presence of niches or built-in flower beds and vertical gardens, require the development of a full-fledged construction project.
For all walls without exception, the general requirements for the foundation are characteristic - the creation of a gravel-sand pillow or its analogue under construction. Building materials, stone and brick chips, gravel, crushed stone, mineral mixtures, coarse or gravel sand, shards, construction waste are laid in layers, creating a kind of pillow along the entire length of the retaining wall.
To seal the drainage cushion, each layer is shed with water. The width of the base should exceed the wall itself by 30%, but the depth is determined depending on the height of the wall and the weight of the materials - from 30 to 50 cm.
All retaining walls with a height of 100 cm or more require foundation construction. Under the foundation also lay a drainage pillow. The erection of the wall is carried out only after the foundation has been poured, solidified and at least several weeks have passed to check its quality and stability.
Features of the construction of retaining walls are determined by the type of design.
Features of the construction of dry retaining walls
Dry retaining walls are structures where natural conditions, the weight of the stone itself and the materials used are used to strengthen the slope. All of them are structures with a slight inclination towards the area to be supported, created on a wide drainage base. For their construction there is no need to fill the foundation and create additional fortifications.
The structure of all dry walls is the same. They begin to build them from the largest stones, laying smaller stones on them and moving them gradually towards the slope:
- To create a pillow at the base of the wall, they dig a deep trench, half the future height of the wall and a width twice the width of the wall itself.
- A dug trench on ¾ is filled with a mixture of coarse sand, gravel, gravel and a mineral mixture - dense, coarse-grained drainage. A gravel-sand pillow is always created in layers, thoroughly wetting each layer after pouring.
- The first stone or slab is set below the soil level - “drown” - on the prepared pillow, placing it at a distance from the bevel.
- The space between the stone or slab and the slope soil is covered with gravel, coarse sand, mineral mixtures, a mixture of gravel, crushed stone, stone chips or construction waste and sand - a protective “buffer” layer.
- Stone by stone, slightly shifting towards a reinforced slope, a wall is erected, carefully filling the free space with the selected drainage or gravel.
Features of the construction of other retaining walls
For concrete retaining walls not only properly selected concrete mixes are needed, but also reinforcing reinforcement and formwork. They are built in two stages - first create a drainage pillow and, if necessary, fill the foundation. Then the formwork and reinforcement are installed and the frame is filled.
For long walls not do without temperature gaps and a special drainage system for water drainage. High-quality drying of the concrete structure is a key point in the construction of concrete retaining walls. Their external side can be painted or additionally lined, achieving similarities with a wall of stone.
The construction of the walls of gabions boils down to the installation of blocks on a prepared sand-crushed stone pillow, which is created according to general principles
Creating Combined Walls carried out on the principle of dry masonry, fastening individual elements with cement mortar (usually unstable, non-planar stones and smaller elements with large plates and boulders are fastened together).