Concrete Retaining Walls: Blocks and How to Choose

Types of retaining wall built with concrete blocks

To deal with a change of level in the garden you don't always need to form and pour a concrete wall. Depending on how much soil has to be held back and what the wall has to do, the Vetonek range offers three solutions: retaining blocks laid in courses with mortar, a stepped green wall where every unit is a planter, and a permanent formwork block for building a reinforced wall.

This guide summarises the sizes, colours and data of each product as given in its technical data sheet. Structural decisions (maximum height, foundations, reinforcement) always rest with the technician responsible for your project.

Retaining blocks laid in courses: Cellorigo, Foncea and Galbárruli

These are vibro-pressed concrete blocks for outdoor use, designed for low retaining walls, planters, raised beds and stepped slopes. They are laid in courses with staggered joints on a firm base, bedded in mortar, and work by gravity. All three come with a matching coping piece to finish the wall and are available in five colours: White, Cream, Grey, Red and Salmon.

• Muro Cellorigo: 10 × 25 × 50 cm block weighing 23 kg (the coping piece weighs 22 kg). Its long 50 cm format makes for quick progress. Pallet of 72 units (≈ 1,680 kg).
• Muro Foncea: 10 × 25 × 25 cm block weighing 12 kg (coping piece 11 kg). Being half the length, it draws curves and circles with even joints, and its weight keeps it easy to handle. Pallet of 144 units (≈ 1,750 kg).
• Muro Galbárruli: the same 10 × 25 × 25 cm size and 12 kg, but with a split face. The split finish is made by breaking the block, leaving a rough, irregular texture like stone masonry. Pallet of 132 units (≈ 1,610 kg).

Fonzaleche green wall: retain and plant at the same time

The Muro Ecológico Fonzaleche is a concrete planter block measuring 20 × 35 × 50 cm and weighing 40 kg per unit, in four colours: White, Cream, Grey and Salmon. It is stacked dry in steps, setting each course back against the slope, and works by gravity. Each block and the area behind are filled with topsoil compacted in layers, and groundcovers or aromatic herbs are planted in them until the wall is covered in green. According to the data sheet, water passes between the units and irrigates the planting. The pallet holds 30 units (≈ 1,225 kg).

The data sheet itself recommends consulting a technician for slopes higher than 1.5 m.

Ochánduri block: a reinforced wall without hiring formwork

The Bloque Ochánduri is a hollow permanent formwork block measuring 30 × 20 × 40 cm, made of vibro-pressed concrete, grey and for outdoor use. It weighs 17.5 kg empty and the coverage is 12.5 units per m²; a pallet of 50 units covers 4 m² of wall (≈ 900 kg).

It works differently from the previous blocks: it is stacked dry with staggered joints over the starter bars of the footing, horizontal reinforcement is placed in each course as specified in the design, and it is then filled with fluid concrete in lifts of 3-4 courses. The block acts as both formwork and finished face. For retaining walls, the data sheet says to waterproof and drain the back of the wall before backfilling with soil. The diameter and spacing of the reinforcement and the maximum height are set by the design or by a technician: the block saves you the formwork, not the calculation.

Base, drainage and coping: what decides whether the wall lasts

• Base: prepare a levelled, buried footing or concrete base and set the first course perfectly level.
• Drainage: if the wall holds back soil, provide drainage at the base and, as the Muro Cellorigo data sheet states, a drainage membrane behind. That same data sheet points out that what ruins a garden wall is not the weight of the soil but the water that collects behind it: leave drainage weep holes every metre in the first course.
• Planters: waterproof the inside face with a membrane or rubber paint before filling with soil, to avoid efflorescence and damp stains on the visible face.
• Split face: rake the mortar joint back slightly; the shadow of the joint strengthens the stone effect.
• Coping: always finish the wall with its coping piece.

How to choose for your case

• Low wall, raised bed or straight planter: Muro Cellorigo.
• Curves, tree rings or raised vegetable beds: Muro Foncea, or Muro Galbárruli if you prefer a stone look.
• Slope you want to cover with plants: Muro Ecológico Fonzaleche.
• Structural retaining wall or basement wall: Bloque Ochánduri, always with a design or a technician.

If you are also enclosing your plot with exposed blocks, see our guide to exposed concrete blocks and the concrete blocks buying guide. For the paving next to the wall, there are concrete pavers and slabs.

You can see the whole range in the Construction of Walls and Concrete Blocks collections.

Frequently asked questions

What is the difference between a gravity retaining wall and a reinforced wall?

A gravity wall is built by stacking blocks in courses and works by its own weight, while a reinforced wall contains steel reinforcement and is filled with concrete. Cellorigo, Foncea, Galbárruli and Fonzaleche work by gravity; the Bloque Ochánduri is a permanent formwork block and is reinforced as specified in the design.

How high can a block retaining wall be?

There is no single figure: it depends on the block, the ground and the design. The data sheets recommend consulting a technician from 1 m for the Muro Cellorigo and from 1.5 m for the Fonzaleche green wall, and for the reinforced wall the maximum height is set by the design.

Do you need drainage behind a retaining wall?

Yes, when the wall holds back soil you should provide drainage. The data sheets specify drainage at the base; the Muro Cellorigo sheet adds a drainage membrane behind and weep holes every metre in the first course, and for the reinforced wall you must waterproof and drain the back of the wall before backfilling.

How many blocks do I need for my wall?

Divide the wall area in m² by the visible face area of one block and add a small margin for breakage. For the Bloque Ochánduri the coverage is 12.5 units per m² and each pallet of 50 units covers 4 m².

Which block is best for a curved planter?

The Muro Foncea, and also the Muro Galbárruli if you want a split face. At 25 cm long, both let you draw curves and circles with even joints without cutting units.

You can see the full data sheets for the Muro Cellorigo, the Muro Ecológico Fonzaleche and the Bloque Ochánduri at Vetonek, and our team is happy to answer any question about which block suits your project.