Muros de Contención
Muros de contención bajos sin mortero ni tiempos de fraguado
Crea terrazas en el jardín sin necesidad de albañil. Los bloques PolyBrick® encajan a presión sobre una base correctamente preparada, de modo que los muros de contención bajos se levantan en pocas horas y se mantienen firmes durante décadas.
Por qué PolyBrick es la solución adecuada
Un muro de contención es la obra que más se pospone. La mampostería tradicional exige mortero, amasado, fraguado y no cometer errores desde el principio. Las traviesas de madera se pudren por la cara posterior, donde no se ven. Los gaviones requieren un ojo experto para que no parezcan simplemente industriales.
PolyBrick elimina la mayor parte de esos problemas. Los bloques se interconectan a presión: sin mortero, sin amasado y sin esperas de fraguado. La obra está terminada en cuanto se coloca el último bloque, no tres días después. Nada se pudre, oxida, contrae ni deforma, por lo que la cara posterior está tan en buen estado en el año quince como la cara vista.
Lo que sí requiere es una cimentación correctamente preparada. Un muro de contención de cualquier tipo concentra la carga en una franja estrecha del terreno, por lo que la zanja, el relleno compactado y la nivelación del primer tendel sostienen todo lo que viene encima. El tipo de cimentación necesaria depende de la altura del muro, el terreno sobre el que se asienta y lo que retiene, así que defínela para tu obra antes de comenzar, sin dar nada por supuesto.
Aplicaciones habituales
- Terrazas y cambios de nivel en jardín
- Contención de parterres y arriates elevados
- Retención de bordes en entradas de vehículos y senderos
- Escalones y plataformas en jardines en pendiente
- Muros bajos de cerramiento y pantalla
- Muros para jardineras y zonas de estar
- Cerramientos para contenedores y leñeras
- Terrazas en huertos y jardines comunitarios
Resumen técnico
| Montaje | Encaje a presión. Sin mortero, sin cemento, sin herramientas especializadas |
| Armado | [Confirmar: diámetro de barra, grado, separación, longitud de anclaje, altura máxima, condiciones del terreno] |
| Cimentación | Excavación hasta terreno firme, compactado y enrasado a nivel. Especificar según la obra |
| Drenaje | Relleno drenante imprescindible. La presión del agua es la principal causa de fallo en muros de contención |
| Material | Polipropileno 100% reciclado, resistente a los rayos UV, fabricado en la UE con polímeros reciclados |
| Mantenimiento | Ninguno. Sin podredumbre, sin oxidación, sin rejuntado, sin tratamientos |
| Compresión | Ensayado a 150 toneladas/m² bajo carga estática fija |
| Vida útil | 25 años bajo garantía |
Conoce los límites antes de empezar
Conviene ser claro en este punto, porque los muros de contención son la única estructura de jardín en la que un error tiene consecuencias que van más allá del aspecto estético.
Un muro de contención retiene tierra, y la tierra es pesada, especialmente cuando está saturada de agua. Cuanto más alto es el muro, mayor es la fuerza que soporta, y la relación no es lineal: un muro el doble de alto soporta considerablemente más del doble de carga.
Para terrazas bajas de jardín, parterres elevados y retención de bordes, un muro PolyBrick correctamente construido sobre una base compactada está muy dentro de su rango de trabajo. Para alturas mayores, para retener una entrada de vehículos o una estructura, en taludes pronunciados o inestables, o en cualquier caso en que el fallo pudiera afectar a un vecino, un edificio o una vía pública, es necesario contar con asesoramiento técnico y diseño de ingeniería. Esto aplica a cualquier material, no solo a este.
Si no tienes claro en qué lado de esa línea se encuentra tu proyecto, indícanos la altura, la pendiente y qué hay por encima y por debajo del muro, y te daremos una respuesta honesta, no una venta.
El drenaje es lo que mantiene en pie un muro
La mayoría de los fallos en muros de contención son fallos de agua. La tierra detrás del muro retiene la lluvia, esa agua tiene peso y no tiene salida, y la presión se acumula hasta que algo cede.
Incorpora un drenaje eficaz desde el principio. Rellena la zona inmediatamente posterior al muro con piedra angular limpia en lugar de la tierra extraída, de modo que el agua descienda a través de la piedra en vez de cargar la cara posterior. Cuando el muro supere un par de hiladas, instala un tubo perforado en la base de ese relleno pétreo para conducir el agua hacia un punto de evacuación adecuado.
La ventaja de PolyBrick en este aspecto es que el agua le es indiferente. No hay nada que se pudra, oxide o descascare, y las juntas no son de mortero que pueda ser arrastrado. Con un drenaje bien ejecutado, el muro es genuinamente libre de mantenimiento.
How it goes up
- Set out the line of the wall and check what is behind it. On a slope, work out where water currently runs, because the wall will interrupt it.
- Excavate a level trench along the line, wider than the wall itself, and dig out any soft or made ground until you reach firm subsoil.
- Lay a woven geotextile in the trench, then fill with compacted granular material and screed it dead level. This base carries the whole wall, and a wall built on an uneven base will show it in every course above.
- Lay the first course and check it with a spirit level along its length and across its width. Everything above follows this course, so take the time.
- Build up in courses, pushing blocks together and staggering the joints between courses so no vertical joint runs through the wall.
- Backfill behind the wall with clean angular stone as you go, not soil, and add drainage at the base of that stone on anything more than a low wall.
- Finish the top course with caps, and bring topsoil up behind to the level you want.
Full detail is in our project guidance, and we are happy to advise on a specific build before you order.
Getting the base right
This is the part that decides whether the wall is still straight in ten years, and it is the part most likely to be rushed.
A retaining wall concentrates a lot of load into a narrow strip of ground. If that ground is soft in places, made ground, or has never been compacted, the wall settles unevenly, courses open up and the line goes.
Dig out to firm subsoil, put a proper compacted granular base in, and screed it level rather than raking it. Check level along the run and across the width. It is an hour of work that determines everything above it, and it is the only part you cannot go back and fix.
Terracing a slope
Two low walls usually beat one tall one.
Where a garden falls away, stepping the level change into two or three shorter terraces reduces the load on each wall considerably, gives you usable planting space between them, and looks better than a single high face. It is also far more forgiving to build.
Set each terrace back from the one below rather than stacking them vertically, and drain each one separately. Water that runs off the top terrace should not arrive behind the bottom one.
Finishing and planting
A PolyBrick wall reads as a deliberate structure rather than a landscaping compromise, and it takes finishing well.
Cap the top course for a clean line. Plant trailing species along the top to soften the face over a season, or run planting in front of the wall so the structure becomes the backdrop rather than the feature.
Where a wall doubles as seating, keep the height comfortable and cap it properly. Where it forms a raised bed, line the soil face if you want to keep the fill separate, though the material itself is inert and will not leach into the soil.
Get it right first time
The one thing worth knowing: drain behind the wall, not just in front of it.
Almost every retaining wall that fails, in any material, fails because of water pressure behind it rather than the weight of soil alone. Saturated ground is dramatically heavier than dry ground, and it pushes.
Backfill with clean angular stone rather than the soil you dug out, run a drain at the base of it, and give that drain somewhere to discharge. It costs a bulk bag of stone and an afternoon. It is the difference between a wall that is still straight in twenty years and one that starts leaning after the first bad winter.
Ask our engineer
Questions about wall height, reinforcement, drainage or whether your project needs designing? Ask below, or get in touch directly.
Common Questions
How high can a PolyBrick retaining wall be built?
For low garden terracing, raised beds and edge retention, a properly built wall on a compacted base is well within its comfort zone. Beyond that the answer depends on the slope, the soil, the drainage and what sits above and below the wall.
For anything taller, anything retaining a driveway or structure, or anything where failure would affect a neighbour, a building or a highway, take engineering advice and have the wall designed. Tell us your height and site and we will give you an honest answer.
What foundation does a PolyBrick retaining wall need?
A trench excavated to firm subsoil, filled with compacted material and screeded dead level. What that foundation should consist of depends on the height of the wall, the ground beneath it and what it is retaining, so establish it for your site rather than assuming.
Whatever you build, that base carries the whole wall: screed it rather than raking it and check level along the run and across the width. It is the only part of the build you cannot go back and fix.
What should I backfill behind a retaining wall with?
Clean angular stone, not the soil you dug out. Most retaining wall failures in any material are water failures: saturated soil is dramatically heavier than dry soil and it pushes.
Free-draining backfill lets water travel down through the stone instead of loading the back face, and on anything more than a low wall a perforated pipe at the base of that stone should take it away.
Do PolyBrick walls need maintenance?
No. There is nothing to rot, rust, spall or repoint, and no mortar joints for water to wash out. The material is UV stabilised recycled polypropylene, so it does not need treating, painting or sealing.
Get the base and the drainage right at the start and the wall is genuinely maintenance free.
How does it compare to sleepers or concrete blocks?
Sleepers rot from the back where you cannot see it, and need replacing. Concrete blocks mean mortar, mixing and curing, and a wall that is finished three days after you stop working.
PolyBrick pushes together dry, so the wall is finished when you stop building, and nothing degrades from the buried side.
Is it better to build one tall wall or two shorter ones?
Two shorter ones, usually. Stepping a level change into two or three terraces reduces the load on each wall considerably, gives usable planting space between them, looks better than a single high face and is far more forgiving to build.
Set each terrace back from the one below and drain each one separately.
Will the plastic leach into my soil?
No. The material is inert recycled polypropylene and will not leach into soil, which is why the same blocks are used for raised beds and planters growing food. It locks the waste plastic up rather than releasing it.
Do I need planning permission for a garden retaining wall?
Low garden walls are usually permitted development, but height limits apply and they are lower where a wall adjoins a highway.
Rules differ across the UK and are tighter for listed properties and conservation areas. Check with your local planning authority if your wall is anything other than low and clearly within the garden.
