Bases para refugios de campo
Una base para refugios que drena y no convierte la construcción en permanente
Los refugios de campo necesitan un suelo firme y nivelado que evacúe la orina y la cama húmeda. Las rejillas IBRAN lo consiguen sin verter hormigón, de modo que el refugio se mantiene limpio, seco y, cuando importa, todavía desplazable.
Por qué la base es determinante aquí
Un refugio de campo es una construcción pequeña que realiza un trabajo exigente. Caballos o ganado permanecen en él durante horas en los peores días del año, sobre el terreno más encharcado, en el único punto que todos han elegido a la vez.
Colocarlo sobre tierra sin preparar y el suelo se apelmaza en pocas semanas. El piso se convierte en una mezcla de barro y cama que no puede limpiarse correctamente, la orina no tiene por dónde drenar y se acumula en la superficie generando amoniaco, y el umbral de entrada se convierte en el punto más hundido de toda la parcela porque todos los animales lo cruzan.
El hormigón resuelve el problema del suelo y crea dos nuevos. Es impermeable, por lo que la orina y el agua de limpieza no tienen otra salida que cruzar la superficie y salir por la puerta. Y constituye una obra permanente, lo que en el caso de un refugio concebido para ser móvil puede marcar la diferencia entre una instalación que requiere licencia urbanística y otra que no.
Una base de rejilla proporciona un suelo firme, nivelado y fácil de limpiar que drena directamente, retiene la cama en lugar de engullirla, y puede levantarse y trasladarse con el refugio si alguna vez es necesario moverlo.
Aplicaciones habituales
- Refugios de campo móviles y sobre patines
- Refugios fijos y boxes sueltos
- Delantales y zonas de acceso al refugio
- Refugios para ganado y casetas para terneros
- Bases para almacenamiento de heno y pienso
- Zonas de comederos circulares y bebederos
- Bases y accesos a estercoleros
- Zonas de estancia junto al refugio
Resumen técnico
| Subbase | 150-250mm de árido compactado, mayor espesor en terrenos blandos o encharcados |
| Relleno | Mezcla granulada angular de 6-14mm, limpia y sin finos, enrasada con la parte superior de las celdas |
| Excavación total | Aproximadamente 200-300mm, según las condiciones del terreno y la profundidad de la rejilla |
| Drenaje | Totalmente permeable al agua. La orina y la cama húmeda drenan a través del suelo en lugar de acumularse en la superficie |
| Cama | Superficie firme y nivelada que retiene virutas o paja y permite una limpieza eficaz |
| Movilidad | Sin obra vertida. Las rejillas pueden levantarse y reinstalarse si el refugio se traslada |
| Vida útil de diseño | 25 años, sujeto a instalación documentada |
| Material | 100% polipropileno reciclado, fabricado en la UE a partir de polímeros reciclados |
Refugios móviles y la cuestión de la permanencia
Conviene entender esto antes de construir nada, porque puede determinar lo que está permitido.
Los refugios de campo móviles suelen recibir un tratamiento urbanístico diferente al de las construcciones permanentes, sobre la base de que son genuinamente desplazables y no están fijados al terreno. Colocarlos sobre una solera de hormigón, o anclarlos a una cimentación permanente, puede debilitar ese argumento y reclasificar el refugio como construcción permanente a efectos de licencia.
Una base de rejilla no es una cimentación vertida. Es una superficie de árido compactado y confinado sobre la que se apoya el refugio, y puede levantarse y reinstalarse en otro lugar. Para un refugio móvil, esta suele ser la solución más adecuada y también la más práctica, porque permite rotar el terreno y llevarse la base si se desea.
El tratamiento urbanístico varía según el municipio y las circunstancias, y depende del refugio, del terreno y del uso que se le dé, no únicamente de la base. Ante cualquier duda, consulte con su ayuntamiento o con el técnico competente antes de ejecutar la obra. Es una consulta breve y considerablemente más conveniente hacerla antes.
¿Qué profundidad de rejilla elegir?
La cifra que identifica una rejilla indica la profundidad de la capa de árido confinado. Los refugios combinan animales estáticos con vehículos pesados ocasionales, por lo que conviene optar por mayor profundidad que en una construcción de jardín.
- IBRAN®-X50 es nuestra recomendación para el delantal de entrada y para toda la base cuando un tractor remolca el refugio, realiza la limpieza o entrega la cama.
- IBRAN®-X40 para el suelo interior del refugio cuando las operaciones se realizan con carretilla y horca en lugar de maquinaria.
- IBRAN®-X30 cuando se coloca sobre firme existente o cuando la cota debe coincidir con un patio adyacente.
En caso de duda, elija la opción más resistente en el umbral de entrada. Es el punto donde todos los animales se detienen, giran y permanecen, y es donde cualquier base falla primero.
Elección del árido
Utilice una mezcla granulada angular de 6-14mm, limpia y sin finos, enrasada con la parte superior de las celdas.
La mezcla granulada importa más aquí que en casi cualquier otra aplicación. Una mezcla se compacta mejor que un tamaño único porque el árido más fino rellena los huecos entre el más grueso, y una superficie densamente compactada es una superficie estable: nada rueda bajo el casco, nada se suelta bajo el peso del animal, y la cama reposa sobre un suelo sólido en lugar de hundirse en él.
Mantenga el árido fino y angular, no grueso ni redondeado. El árido suelto o sobredimensionado puede moverse bajo el casco, dañar la suela o alojarse en una herradura, y en un refugio el animal permanece sobre él durante horas.
Excluya los finos por completo. Cualquier material con polvo o escalpados se apelmazará, retendrá orina y agua en la superficie y reproducirá exactamente el problema de amoniaco que la base pretendía evitar.
How it goes in
- Choose the position carefully. Shelters want to sit on the driest ground available, with the back to the prevailing wind and the opening away from it, and with somewhere for water to go that is not the doorway.
- Mark out the base well beyond the shelter footprint, taking it out furthest at the opening. The apron outside the door is not optional: it is where the wear actually happens.
- Dig the mud out down to firm subsoil. Poached ground has no bearing capacity, and anything laid on it will sink into it over one winter.
- Lay a woven geotextile across the formation, lapping joins by at least 300mm. On soft ground it is structural, stopping the sub-base punching down and stopping soil pumping up into your surface.
- Lay and compact the sub-base in 50mm layers, to a depth that suits the ground and the vehicles that will come to the shelter.
- Blind with a thin layer of grit sand and screed it level, with a slight fall away from the shelter towards the opening or to one side.
- Push-fit the grids together, staggering the joints. Cut to line around skids, posts and the door opening with a saw.
- Fill the cells with a 6-14mm angular graded blend, level with the cell tops, brushing in thoroughly so no cell is left hollow.
- Set the shelter in position and check it sits level on its skids or bearers before it is used.
Full step-by-step detail is in our installation guides.
The apron outside the door
If you only reinforce one part of a shelter site, make it this.
Every animal using the shelter passes through one opening, and most of them stop in it: half in, half out, watching the field, standing in the same spot for hours. That doorway takes more traffic and more standing time than the whole of the rest of the field put together, and it is the first place to poach.
Take the base out at least a shelter's depth beyond the opening, and wider than the opening on both sides. Where a group shares the shelter, take it further still, because the animals that cannot get in will stand as close as they can and churn the ground doing it.
Get the falls right at the same time. Water running off the shelter roof lands exactly here, and if it has nowhere to go it will undo the work.
Bedding, mucking out and drainage
A permeable base changes how the shelter works day to day.
Urine and moisture drain down through the stone instead of soaking into bedding and sitting on the floor, which keeps the bed drier, reduces ammonia and means bedding goes further. There is no low corner collecting liquid and no wash of muck out through the doorway.
Mucking out is easier because you are working on a firm, level surface: a fork does not dig into the floor, and a barrow wheels rather than sinks. Where a tractor and bucket do the job, specify the deeper grid across the whole floor so the base takes the machine as well as the animals.
Where drainage from a shelter could reach a watercourse, ditch or borehole, check what applies to you before building. Rules on managing run-off from areas used by livestock vary and are worth confirming with your local authority or environmental regulator.
Anchoring and wind
Field shelters blow over. They are large, light, and usually in the most exposed spot on the holding.
A mobile shelter on skids relies on its own weight and its skids bedding into the ground, and a firm level base makes that behaviour more predictable rather than less. Where the manufacturer specifies ground anchors, these can fix through the base into the compacted sub-base beneath, which is another reason to compact that layer properly rather than tipping and raking it.
Follow whatever the shelter manufacturer specifies. It is their structure, and their anchoring recommendation accounts for its size, shape and exposure in a way that generic advice cannot.
Get it right first time
The one thing worth knowing: build the base bigger than the shelter.
A base that stops at the walls solves the floor and leaves the real problem untouched. The mud simply forms at the threshold instead, and everything then walks through it to get inside, dragging it onto the clean floor you just built.
Extend the base out into the field at the opening, round the sides where animals shelter from wind, and to wherever a barrow or tractor comes and goes. The extra area is the cheapest part of the job and it is what turns a dry shelter into a dry shelter you can actually reach.
Ask our engineer
Questions about depths, apron sizing, drainage or which system suits your shelter? Ask below, or get in touch directly.
Common Questions
Do I need a concrete base for a field shelter?
No, and for a mobile shelter concrete is often the wrong answer. A grid base gives a firm, level, cleanable floor that drains straight through rather than holding urine and wash-down on the surface, and it is not a poured foundation, so it can be lifted and relaid if the shelter moves.
It is also considerably quicker to build and needs no curing time.
Will a concrete base make my mobile field shelter permanent?
It can affect how the shelter is treated. Mobile field shelters are often treated differently from permanent buildings on the basis that they are genuinely movable and not fixed to the ground, and standing one on a poured slab or bolting it to a permanent foundation can undermine that.
Planning treatment varies by authority and circumstance, so ask your local planning authority before building if there is any doubt.
How deep should a field shelter base be?
Around 200mm to 300mm in total, made up of 150mm to 250mm of compacted MOT sub-base plus the grid depth, with more on soft or wet ground.
Dig out to firm subsoil first: poached ground has no bearing capacity, and anything laid on it will sink into it over one winter.
What stone should I use in a field shelter base?
A 6mm to 14mm angular graded blend, clean and free of fines, filled level with the cell tops. A blend packs tighter than a single size, and a densely packed surface is a stable one, so nothing rolls underfoot and bedding sits on a solid floor rather than sinking into it.
Keep the stone fine and angular: loose or oversized material can move under a hoof, bruise a sole or lodge in a shoe.
How far should the base extend beyond the shelter?
Take it at least a shelter's depth beyond the opening and wider than the opening on both sides. Every animal passes through one doorway and most of them stand in it, so that spot takes more traffic and standing time than the rest of the field put together.
Where a group shares the shelter, extend it further, because animals that cannot get in will stand as close as they can.
Does a permeable base help with bedding and ammonia?
Yes. Urine and moisture drain down through the stone instead of soaking into the bedding and sitting on the floor, which keeps the bed drier, reduces ammonia and makes bedding go further.
There is no low corner collecting liquid and no wash of muck out through the doorway.
Is it easier to muck out than bare ground?
Considerably. You are working on a firm level surface, so a fork does not dig into the floor and a barrow wheels rather than sinks.
Where a tractor and bucket do the job, specify the deeper 50mm grid across the whole floor so the base takes the machine as well as the animals.
Which grid depth should a field shelter use?
The 50mm grid for the entrance apron, and for the whole base where a tractor tows the shelter, mucks it out or delivers bedding. The 40mm for the shelter floor where handling is done by barrow and fork. The 30mm where you are laying over existing hard standing or matching an adjoining yard level.
If in doubt, take the heavier option at the doorway.
How do I anchor a field shelter on a grid base?
Follow the shelter manufacturer's recommendation, since it accounts for the structure's size, shape and exposure. A mobile shelter on skids relies on its own weight and its skids bedding in, and a firm level base makes that behaviour more predictable.
Where ground anchors are specified, they can fix through the base into the compacted sub-base beneath, which is a further reason to compact that layer properly.
Can the base be moved with the shelter?
The grids can be lifted and reinstated, which suits ground rotation or a shelter that changes position.
Bear in mind the excavation and sub-base stay behind, so the reusable element is the grid itself rather than the whole build-up.
Ask our engineer
Questions about depths, sub-base, edging or which system fits your project? Ask below.
