Types of retaining walls for a house

If you are considering buying or building a house on a sloping plot, one of the first questions that arises is: how are we going to retain the soil? Choosing between the different types of retaining walls is key to ensuring stability, safety, and efficient use of the land.

In this technical article, we explain what a retaining wall is, when it is necessary to build one, and we analyse the different types, along with their advantages and disadvantages.

What is a retaining wall?

A retaining wall is a structure designed to resist and hold back the lateral pressure of soil masses or other loose materials, especially on sloping terrain. Its purpose is to prevent landslides, erosion, or collapses that could put buildings or habitable spaces at risk.

These walls make it possible to modify the site’s topography to create flat, stable surfaces where none existed before, which is essential in construction projects on uneven ground. They also help control water drainage, preventing build-ups that could weaken the soil.

There are different types of retaining walls, which vary depending on the terrain, the type of load they must withstand, and the project’s architectural design. Some work by gravity, others through structural reinforcement, and the choice directly affects safety, cost, and how well the work integrates into the landscape.

Types of retaining walls for a house

Discussing the types of retaining walls for a house means understanding a wide range of construction solutions, from traditional methods such as dry stone to technical systems such as diaphragm walls with micropiles.

To better understand how they work, they can be classified according to how they resist earth pressure. This organisation makes it possible to distinguish which types are best suited to landscaped outdoor areas and which are recommended when there are structures above.

This distinction makes it easier to choose the most efficient and safest system for each case.

Gravity retaining walls

Among the different types of retaining walls for a house, gravity walls are particularly suitable for outdoor areas and landscaped terrain. This type of wall relies on its own weight to counteract soil pressure, so it often does not require deep foundations, which reduces costs and simplifies execution.

However, although their construction may seem simpler, in certain cases it requires specialised labour, especially when materials such as natural stone or mortarless blocks are used.

Dry stone walls

The dry stone wall is one of the oldest and most traditional types of retaining walls for a house. It has been used for centuries in different regions of Spain, such as the Catalan Pyrenees or rural areas of the Balearic Islands, and many examples can still be found in the rural landscape.

It is made of stones stacked without using mortar or cement. The stones usually have flat shapes on their base and top, which makes placement and stability easier. The wall’s strength relies solely on the shape, weight, and interlocking of the stones. Although they are visually very attractive and integrate perfectly into natural settings, this type of wall requires highly specialised labour.

Today, they are used less frequently for soil retention in homes, as they are not designed to support large structural loads. However, they can still be a viable option in outdoor or landscaped areas where high strength is not required.

Rockery wall

The rockery wall shares similarities with the dry stone wall, as it is also built with stones, although in this case flat shapes and precise interlocking are not sought. The rocks are placed on top of one another more freely, resulting in very thick walls with a pyramidal shape.

This type of retaining wall is used mainly when a more natural appearance is desired. By leaving spaces between the stones, it allows plants to grow, which helps it blend into gardens or green areas. In addition, these open spaces improve water drainage, reducing the risk of build-ups or seepage.

To retain large volumes of soil, large rocks must be used, which involves heavy machinery for transport and placement. Depending on the type of terrain, it may be necessary to combine it with tie rods or even a concrete wall to ensure stability.

Precast block walls

Among the different types of retaining walls for a house, precast block walls represent a modern and versatile solution. They are inspired by the principles of dry stone, as they also rely on stacking, but they incorporate industrial materials such as concrete, ceramic, or reconstituted stone.

These blocks can be standard or custom-made, depending on the project’s needs. Some even include cavities for planting vegetation, which makes it possible to integrate the wall into landscaped settings and reduce its visual impact. The blocks are usually stacked and, depending on the design and the loads to be supported, they can be bonded with mortar or reinforced with steel rebar.

Formal flexibility is one of their main advantages: walls can be built completely vertical or with a slope like a berm. This adaptability, together with ease of installation, makes precast block walls a very popular option both for homes and for outdoor spaces.

Gabion walls

Gabion walls are another type of retaining wall for a house that has gained popularity in recent years. They are made up of metal structures in the form of cages or containers that are filled with relatively small stones.

This type of wall is used mainly in landscaping projects and for soil retention in outdoor spaces. They are common on roads or in public areas, although they are not designed to support very high loads beyond the weight of the soil they retain.

Gabion walls work based on the mass of the stones contained in the cages, which provides stability and strength to the whole. Their appearance is quite natural, as the stones remain visible within the metal mesh, which also allows good water drainage thanks to the open spaces between them.

In addition, gabion walls offer good acoustic performance, which is useful in noisy environments. Although most are filled only with stones, it is possible to combine other materials such as wood or bricks inside the cages, always taking into account the weight and the retaining capacity required for the terrain.

Reinforced earth / reinforced soil walls

When a solution is sought that maintains a natural look on the site, reinforced earth walls are an effective option. This technique consists of reinforcing the soil itself by incorporating steel meshes that prevent collapse and sliding, without the need to build a visible wall.

This system is similar to reinforced concrete, in which a base material is strengthened with a metal structure to increase its strength and stability. The result is an almost natural slope that creates minimal visual impact and integrates easily with the surroundings.

Reinforced earth walls are especially useful on sloping terrain where retention is required without resorting to rigid, bulky structures, combining functionality and aesthetics efficiently.

Mass concrete wall

The mass concrete wall is a technique used in certain specific cases for soil retention, although it is not widely used. This is mainly because unreinforced concrete, that is, without steel reinforcement, can be vulnerable under high earth pressures.

For this type of wall to work properly, it must be built with considerable thickness, as its strength depends on the material’s own weight. Therefore, the greater the volume of soil to be retained, the greater the wall’s weight and thickness must be to ensure stability.

Structural walls

Structural walls are a type of retaining wall designed to withstand not only earth pressure, but also additional loads from structures built above. They are made of reinforced concrete, which provides high strength and durability. Because they must withstand high forces, their thickness increases considerably as the wall height increases.

This type of wall is one of the most widely used today, thanks to its relatively straightforward construction process and its cost-effectiveness compared to other solutions. Structural walls are classified according to their shape and their location on the site, adapting to different conditions and retention requirements.

Cantilever wall

Cantilever retaining walls are walls to which a horizontal base is added as a foundation. The risk with reinforced concrete retaining walls is that, being very slender, they could overturn; this is why it is important to calculate the horizontal base that remains buried and precisely prevents overturning.

The foundations of these walls are designed according to the type of subsoil and its bearing capacity, as the wall’s stability will depend on the stability of the ground.

Counterfort walls

Counterfort walls are retaining structures that incorporate vertical reinforcements arranged perpendicular to the face of the main wall. These elements increase structural capacity, allowing the wall to withstand high earth pressures, especially in very tall walls, where there is a greater risk of overturning or displacement.

Historically, counterforts have been widely used in monumental architecture, such as Gothic cathedrals or gravity dams, where they help distribute loads and provide additional stability. In earth retention, they improve anchorage to the ground and optimise structural behaviour.

Diaphragm walls

Diaphragm walls are a type of reinforced concrete retaining wall built directly embedded into the ground, without the need for a shallow horizontal base. This system makes it possible to retain great depths of soil and act at the same time as a foundation and as a structural wall.

As they do not have a conventional footing to prevent overturning, their stability is ensured by deep anchors—cables or bars—inserted into the subsoil. They are widely used in dense urban construction or on sites with difficult access.

Which type of retaining wall should we use?

Choosing the type of retaining wall cannot be based solely on the direct cost of the construction system. While options such as precast block walls or rockery walls may seem more economical in the short term, it is essential to consider the overall impact each solution has on the site. The volume of soil that must be excavated, the machinery required, and the type of foundations directly influence both the budget and the project’s ecological footprint.

For example, a diaphragm wall may be more expensive initially due to its specialised technical execution, but it makes it possible to minimise earthworks, which is valuable in urban or protected environments. On the other hand, systems such as reinforced earth or gabion walls offer more natural solutions with low visual impact, aligning with the principles of architecture that is more integrated with its surroundings.

Choosing with technical and environmental criteria

Selecting the right retaining system involves a comprehensive evaluation of the project: from the site’s geotechnical conditions to access for machinery or the type of structural load expected. But also—and with increasing urgency—it is essential to consider the environmental impact of each decision. This impact refers both to the physical alteration of the land and to energy consumption, waste generation, and the ecological footprint of materials. Minimising it means opting for solutions that respect the topography, reduce earthworks, and prioritise durable, recyclable construction systems or those with low embodied energy. Within the framework of architecture consistent with NZIB (Nearly Zero Impact Buildings), each wall must not only retain the soil, but also uphold a commitment to the environment.