Bases para casetas de jardín y espacios de ocio exterior
Una base para un espacio en el que realmente pasas tiempo
Una caseta de jardín es una estancia, no un trastero. Las rejillas IBRAN proporcionan una base firme, nivelada y drenante que mantiene el suelo seco y la estructura a escuadra, y se integra en el jardín como un elemento de paisajismo, no como una losa de hormigón.
Por qué la base importa más que la propia estructura
Una caseta de jardín exige más de su base que cualquier otra construcción de exterior, precisamente por lo que ocurre dentro de ella.
La gente pasa horas sentada en su interior. Hay alfombras, cojines, libros, un sofá, a veces un escritorio y un portátil, con frecuencia instalación eléctrica e iluminación. Todo eso es incompatible con la humedad de una manera que una cortacésped no lo es. Un suelo de cobertizo ligeramente húmedo por debajo sigue siendo un cobertizo. Un suelo de caseta de jardín ligeramente húmedo por debajo huele a humedad en una temporada y arruina el mobiliario blando en dos.
Además, se ve. Una caseta de jardín se coloca habitualmente como punto focal al fondo del jardín, de modo que la base es visible desde la vivienda durante todo el año. Un zócalo de hormigón gris transmite obra; un acabado limpio de grava transmite paisajismo.
Y soporta más peso del que se espera. Mobiliario, ocupantes, una estufa de leña, un depósito de agua en una esquina, a veces una pequeña tarima. Distribuido de forma irregular sobre una base que asienta de forma irregular, la estructura va perdiendo la escuadra poco a poco.
Una base de rejilla resuelve los tres problemas: el árido confinado proporciona una plataforma rígida que no asienta de forma diferencial, la superficie permanece totalmente permeable al agua para que la humedad drene y el aire circule bajo el suelo, y la grava se convierte en un elemento deliberado del jardín en lugar de una intrusión en él.
Aplicaciones habituales
- Casetas de jardín y espacios de ocio exterior
- Oficinas en casa y estudios
- Cabañas de madera y chalets
- Pérgolas, glorietas y bares de jardín
- Zonas de jacuzzi y spa
- Tarimas y plataformas elevadas
- Senderos de acceso y umbrales
- Sustitución de losas o bases pavimentadas deterioradas
Resumen técnico
| Subbase | 100-150mm de árido compactado, mayor espesor para cabañas grandes o contenidos pesados |
| Relleno | Mezcla graduada 6-14mm, gravilla limpia y angular, enrasada con la parte superior de las celdas |
| Excavación total | Aproximadamente 140-190mm, según la profundidad de la rejilla y la subbase |
| Acabado | Árido decorativo opcional, coordinado con el jardín |
| Drenaje | Totalmente permeable al agua. Sin encharcamiento junto a la estructura, sin suelo húmedo |
| Accesibilidad | Un relleno graduado y bien compactado proporciona un acceso firme apto para vehículos con ruedas |
| Vida útil de diseño | 25 años, con instalación documentada |
| Material | 100% polipropileno reciclado, fabricado en la UE a partir de polímeros reciclados |
Mantener el interior seco
Esto es lo que diferencia una caseta de jardín agradable en marzo de una que solo es utilizable en julio.
La humedad penetra en un espacio de jardín por debajo con mucha más frecuencia que a través del tejado. La humedad asciende del terreno, condensa contra un suelo frío y no tiene salida, y la primera señal suele ser un olor antes que una mancha.
Una base permeable rompe ese ciclo. El agua drena hacia abajo a través del árido en lugar de acumularse bajo la estructura, y el aire circula por el hueco bajo el suelo en lugar de estancarse en él.
Construya sobre largueros para dejar un espacio ventilado libre, prolongue la base más allá de los muros para que el agua de escorrentía del tejado caiga sobre el árido, y mantenga la vegetación recortada en los laterales. Cuando la estructura esté aislada y se use durante todo el año, merece la pena consultar con el fabricante la incorporación de una lámina impermeabilizante en el paquete de suelo, porque cuanto mejor aislada esté la estancia, más importante es que la humedad no pueda entrar por debajo.
Integrar la base en el jardín
Este es el apartado que no existe para un cobertizo, y es donde una base de grava justifica su elección desde el punto de vista visual.
Amplíe la base bastante más allá de la huella de la construcción y deja de ser una base para convertirse en un entorno: un zócalo de grava en el que se asienta la estructura, suficientemente amplio para una silla junto a la puerta, una mesa, un par de macetas. Transmite intencionalidad y le proporciona un lugar seco donde estar que no es césped.
El árido decorativo funciona perfectamente aquí, de modo que la superficie puede coordinarse con los senderos existentes, la plantación o la vivienda. La piedra local suele quedar mejor que la importada y resulta más económica de entregar.
Cuando la caseta linda con una tarima o una terraza pavimentada, lleve la base de rejilla hasta ella y termine a nivel, sin escalón y sin junta que acumule hojas. Donde limita con el césped, un remate perimetral le da una línea limpia y sirve a la vez de guía para la cortacésped.
¿Qué profundidad de rejilla elegir?
El número de una rejilla indica la profundidad de la capa de árido confinado. Las casetas de jardín son más pesadas que los cobertizos y están ocupadas, así que opte por una profundidad ligeramente mayor que la que elegiría para un almacén.
- IBRAN®-X40 es la opción habitual para la mayoría de casetas de jardín y espacios de ocio exterior: profundidad suficiente para la estructura, el mobiliario y las personas en su interior.
- IBRAN®-X30 para estructuras más pequeñas, pérgolas y glorietas, o cuando los niveles de acabado deben ajustarse a una terraza o umbral existente.
- IBRAN®-X50 para cabañas de madera grandes, construcciones con estufa de leña o acabado interior pesado, o cuando hay un jacuzzi de por medio.
Los jacuzzis merecen una consideración aparte: llenos y en uso, son considerablemente más pesados que cualquier otro elemento que pueda instalarse en un jardín. Compruebe el peso en carga declarado por el fabricante del jacuzzi y dimensione la subbase específicamente para ese valor.
How it goes in
- Check the manufacturer's base requirements first. Larger cabins often specify a minimum base size, a bearer spacing or a particular level tolerance, and it is easier to build to it than to discover it on delivery day.
- Mark out the base generously: at least 100mm beyond the building on every side as a minimum, and considerably more where you want a usable apron.
- Clear turf, roots and soft soil to firm ground, and check the ground falls away from the building position.
- Excavate to your total depth: sub-base plus grid depth, typically 140-190mm.
- Lay a woven geotextile across the dig, lapping joins by at least 300mm and taking it up the sides.
- Add the sub-base and compact it in layers. 100-150mm of MOT, compacted properly, is what stops an occupied building settling unevenly over the years.
- Blind with a thin layer of grit sand and screed it level. Check with a straight edge and spirit level in both directions, and check the diagonals of the marked area match.
- Push-fit the grids together, cutting the perimeter to line with a hand saw.
- Fill the cells with a 6-14mm graded blend, level with the cell tops, brushing in so no cell is left hollow.
- Set the building on bearers, check square and level, then fix down.
Full step-by-step detail is in our installation guides.
Services and the things you forget
A summerhouse is usually the one garden building that ends up with power, and occasionally water, and both are considerably easier to deal with before the base goes down.
Run a duct under the base while it is open, even if you have no immediate plans for electrics. An empty conduit costs almost nothing at this stage and saves lifting a finished surface later, which is the point at which most people give up and run a cable across the lawn instead.
Think about where the water goes, too. A summerhouse roof concentrates runoff at its eaves or downpipe, and a permeable base handles ordinary rainfall comfortably but not a downpipe discharging in one spot for years. Direct it into a butt, a soakaway, or at least away from the corner of the building.
Any electrical work should be done by a qualified electrician and will usually need to comply with Part P.
Thresholds, steps and access
A summerhouse is entered and left constantly, and the threshold is where a base either works or annoys you daily.
Take the base out further on the door side than anywhere else, so there is a proper standing area rather than a step straight onto grass. If the building has a veranda or decking, run the base underneath and beyond it.
Where the garden room is used year round or by anyone with limited mobility, a densely packed graded fill gives a firm surface that takes a wheelchair or a walking frame, which loose gravel does not. Keep the finished level flush with the threshold rather than leaving a lip, and run the approach path in the same surface so there is no transition to catch a wheel.
Sloping gardens
Summerhouses are often sited at the end of a garden, which is frequently the part that is not flat.
For a gentle slope, dig into the high side rather than building up the low side: material you have added is always less stable than ground you have not disturbed, and an occupied building will find any weakness over time.
On a steeper slope you will need a retained edge, and it is worth getting that right rather than improvising, because it is holding back the ground your building sits on. Where the drop is significant, consider whether a deck platform is a better answer than a very deep cut, and take advice on anything structural.
Get it right first time
The one thing worth knowing: build the base bigger than you think you need.
Almost nobody regrets a generous base. Plenty of people regret a tight one, and it is the single most common thing to wish you had done differently, because it is the one thing that cannot be changed once the building is up and the planting has gone in around it.
An extra half metre of gravel apron costs very little at construction and completely changes how the building is used: a chair outside the door, a table in the sun, somewhere dry to stand in March, room to get round the outside to treat the timber. Stop the base at the walls and you have a building you go inside; extend it and you have a place in the garden.
Ask our engineer
Questions about depths, base sizing, sloping ground or hot tub loading? Ask below, or get in touch directly.
Common Questions
Is a gravel grid base suitable for a summerhouse or garden room?
Yes, and it suits an occupied building particularly well. Confined stone gives a rigid platform that does not settle in patches under furniture and people, and the surface stays fully permeable so moisture drains away rather than collecting under the floor.
It also finishes as a considered part of the garden rather than a concrete apron in view of the house.
How do I stop a garden room getting damp?
Damp usually comes from underneath rather than through the roof: moisture rises from the ground, condenses against a cold floor and has nowhere to escape. A permeable base lets water drain down through the stone instead of sitting under the building, and bearers keep a ventilated gap so air moves through.
Extend the base beyond the walls so roof runoff lands on stone, and keep planting cut back from the sides.
How deep should a summerhouse base be?
Around 140mm to 190mm in total: 100mm to 150mm of compacted MOT sub-base plus the grid depth, with more for larger cabins or heavy contents.
Compact the sub-base in layers rather than tipping and raking it, because that is what stops an occupied building settling unevenly over the years.
Which grid depth do I need for a summerhouse?
The 40mm grid is the sensible default for most summerhouses and garden rooms: enough depth for the building, the furniture and the people in it. Use 30mm for smaller structures, gazebos and pergolas, or where levels must match an existing patio.
Use 50mm for large log cabins, buildings with a wood burner or heavy fit-out, or where a hot tub is involved.
How big should the base be?
At least 100mm beyond the building on every side as a minimum, and considerably more where you want a usable apron. An extra half metre of gravel costs very little at construction and completely changes how the building is used: somewhere to put a chair, a table, or just somewhere dry to stand.
It is the most common thing people wish they had done, and it cannot be changed once the building is up.
Can I run electrics to the summerhouse?
Run a duct under the base while it is open, even if you have no immediate plans for power. An empty conduit costs almost nothing at that stage and saves lifting a finished surface later.
Any electrical work should be carried out by a qualified electrician and will usually need to comply with Part P.
Will a gravel base take a hot tub?
It can, but design for it specifically. Filled and occupied, a hot tub is far heavier than anything else likely to sit in a garden, so check the manufacturer's stated loaded weight and build the sub-base and grid depth against that figure rather than against the building.
The 50mm grid with a deeper compacted sub-base is the usual answer.
Is the base wheelchair accessible?
A densely packed graded fill gives a firm surface that takes a wheelchair, walking frame or pushchair, which loose gravel does not.
Keep the finished level flush with the threshold rather than leaving a lip, and run the approach path in the same surface so there is no transition to catch a wheel.
What gravel should I finish it with?
A 6mm to 14mm graded blend, angular and clean, filled level with the cell tops. Decorative aggregate works well here so the surface can be matched to existing paths, planting or the house, and local stone usually looks better than imported and costs less to deliver.
Avoid rounded shingle, which shifts underfoot, and anything with fines, which binds and stops the base draining.
Can I build a summerhouse base on a slope?
Yes. For a gentle slope, dig into the high side rather than building up the low side, since added material is always less stable than undisturbed ground and an occupied building will find any weakness.
On a steeper slope you will need a properly retained edge, and where the drop is significant it is worth considering whether a deck platform is a better answer and taking advice on anything structural.
Ask our engineer
Questions about depths, sub-base, edging or which system fits your project? Ask below.
