Základy pre záhradné domčeky
Základ pre záhradný domček bez betónu
Rovný, pevný a priepustný za jedno popoludnie. Mriežky IBRAN vytvoria základ pre záhradný domček, ktorý udrží podlahu suchú a konštrukciu v pravom uhle – bez miešania, bez debnenia a bez čakania na vytvrdnutie.
Prečo základ rozhoduje viac ako samotný domček
Záhradné domčeky takmer nikdy nezlyhávajú kvôli sebe samým. Zlyhávajú kvôli tomu, čo je pod nimi.
Ak postavíte drevenú konštrukciu priamo na zeminu, na dosky uložené v piesku alebo na niekoľko podkladových kameňov v rohoch, nastanú dve veci. Podložie sa pohybuje, rám sa skrúti, dvere prestanú zatvárať a strecha začne prepúšťať vodu. A vlhkosť sa hromadí pri nosníkoch, pretože nič pod nimi neodvádza vodu, takže podlaha hnije zdola, kým steny sú ešte v poriadku.
Betónová doska pohyb eliminuje, ale prináša vlastný problém: je nepriepustná, takže voda, ktorá na ňu dopadne, musí niekam odísť, a zvyčajne skončí ako kaluž okolo okraja, ktorá udržiava drevo mokré. Je to tiež celodenná práca, miešačka, dovoz kameniva a základ, ktorý zostane navždy, aj keď domček odídete.
Mriežkový základ rieši oboje. Kamenivo uzavreté v bunkách vytvára pevnú, rovnú plochu, ktorá sa neusadzuje nerovnomerne, pričom celá konštrukcia zostáva plne priepustná – dažďová voda odteká priamo cez základ a pod stavbou cirkuluje vzduch namiesto toho, aby sa hromadila vlhkosť.
Kde sa toto riešenie osvedčuje
- Záhradné domčeky od veľkosti 6x4 nahor
- Dielne a hobby priestory
- Sklady bicyklov a kosačiek
- Sklady dreva a nádob na odpad
- Plastové a kovové záhradné domčeky
- Kurníky a prístrešky pre zvieratá
- Stanoviská pre olejové nádrže a zariadenia
- Náhrada poškodenej betónovej dosky alebo dlažby
Prehľad parametrov
| Podkladová vrstva | 75–100 mm zhutneného štrkodrvového lôžka pre bežný záhradný domček. Viac pre dielňu alebo ťažký obsah |
| Výplňové kamenivo | Frakcia 6–14 mm, hranolovité a čisté, vyplnené po hornú hranu buniek |
| Celková hĺbka výkopu | Približne 110–140 mm v závislosti od hĺbky mriežky a podkladovej vrstvy |
| Čas realizácie | Jedno popoludnie pre bežný základ záhradného domčeka, jedna osoba |
| Náradie | Lopata, hrable, ručná píla a vibračná doska, ak si ju prenajmete |
| Odvodnenie | Plne priepustné. Voda odteká cez základ namiesto toho, aby sa hromadila okolo stavby |
| Návrhová životnosť | 25 rokov pri doloženom postupe inštalácie |
| Materiál | 100% recyklovaný polypropylén, udržateľne vyrobený v EÚ |
Prečo je lepší ako alternatívy
Oproti betónovej doske: žiadne miešanie, žiadne debnenie, žiadne čakanie na vytvrdnutie, žiadny odvoz odpadu a žiadna trvalá konštrukcia, ktorá zostane po odstránení domčeka. Je tiež výrazne lacnejší pre bežnú záhradnú stavbu, keď zarátate kamenivo, cement a prenájom zariadení.
Oproti betónovej dlažbe: dosky uložené v piesku sa usadzujú jednotlivo, a keď jedna klesne, celá stavba ju nasleduje. Mriežkový základ rozkladá zaťaženie po celej ploche, takže platforma zostáva rovná ako jeden celok.
Oproti dreveným nosníkom na podkladových kameňoch: kamene sa zanárajú do mäkkej zeminy rôznou rýchlosťou a medzery medzi nimi zachytávajú lístie a vlhkosť. Súvislý základ tento problém nemá.
Oproti žiadnemu základu: toto je najčastejší spôsob osadenia záhradného domčeka a dôvod, prečo sú podlahy toľkých domčekov v rohoch mäkké.
Ktorá hĺbka mriežky?
Číslo v názve mriežky vyjadruje hĺbku vrstvy uzavretého kameniva. Pre záhradné stavby sú zaťaženia skromné a rozložené cez nosníky, takže plytšia voľba je zvyčajne správna.
- IBRAN®-X30 pre väčšinu záhradných domčekov. Najplytší výkop, najmenej kameniva a najmenej výkopku na odvoz – čo je dôležité, keď jediná cesta do zadnej časti záhrady vedie cez dom.
- IBRAN®-X40 pre väčšie dielne, ťažký obsah alebo tam, kde základ slúži aj ako trasa pre fúrik alebo kosačku.
- IBRAN®-X50 tam, kde na základ bude vjažďať vozidlo, napríklad garážová stavba alebo sklad jazdnej kosačky s pravidelným prístupom.
Navrhovať väčšiu hĺbku, ako domček potrebuje, znamená platiť za kamenivo, ktoré musíte zakopať a doniesť cez záhradu.
Výber kameniva
Použite frakciu 6–14 mm, hranolovitú a čistú. Plytšia bunka vyžaduje jemnejšiu hornú frakciu, aby sa kamenivo úplne uložilo, a zmes sa zhutní tesnejšie ako jednotná frakcia, pretože menšie kamene vypĺňajú medzery medzi väčšími.
Táto hustota je to, čo vám dáva rovnú a stabilnú plochu. Plne vyplnená bunka prenáša zaťaženie cez kamenivo do podložia; čiastočne vyplnená bunka ho prenáša cez plast, a pod nosníkom nesúcim roh stavby sa to prejaví ako pokles.
Vyhýbajte sa okrúhlemu riečnemu štrku, ktorý sa kotúľa namiesto toho, aby sa zaklínil, a akémukoľvek materiálu obsahujúcemu jemné čiastočky alebo prach, ktoré upchávajú povrch a zabraňujú odvodneniu. Priepustnosť je polovicou toho, za čo platíte.
How it goes in
- Mark out the base. Make it larger than the shed footprint by at least 100mm on every side, so rain running off the roof lands on stone rather than on soil next to the timber.
- Check the ground falls away from the building position rather than towards it, and clear any turf, roots and soft soil down to firm ground.
- Excavate to your total depth: sub-base plus grid depth. For a typical garden shed that is around 110-140mm.
- Lay a woven geotextile across the dig, lapping joins by at least 300mm and taking it up the sides. This stops the sub-base mixing into the soil beneath and keeps the base performing.
- Add the sub-base and compact it. 75-100mm of MOT is ample for a garden shed, compacted in one or two layers rather than tipped and levelled.
- Blind with a thin layer of grit sand and screed it level. Check it with a straight edge and a spirit level in both directions: this is the layer that decides whether your shed door shuts.
- Push-fit the grids together across the base, cutting the perimeter to line with a hand saw.
- Fill the cells with a 6-14mm graded blend, level with the cell tops, and brush it in so no cell is left hollow.
- Set the shed on bearers across the base and check it is square and level before fixing anything together.
Full step-by-step detail is in our installation guides.
Make the base bigger than the shed
This is the single most useful thing to get right, and it costs almost nothing at the time.
A shed roof throws water off its edges. If the base stops at the shed footprint, that water lands on soil, splashes soil back up against the boards, and keeps the bottom of the building permanently damp. Extend the base 100mm or more beyond the shed on every side and the runoff lands on free-draining stone instead, where it disappears.
The margin also gives you somewhere to stand while you build, somewhere for the door to swing over, and a clean strip to walk round the building for maintenance rather than treading a muddy path into the lawn.
If the shed has a door on the long side, take the base out further on that side still. It becomes the threshold you stand on every time you open it.
Keeping the floor dry
Rot in a shed floor almost always starts underneath, and it starts because moisture has nowhere to go.
Set the building on bearers rather than directly on the base, so there is an air gap under the floor. Run the bearers in the direction that lets air pass through, keep vegetation cut back from the sides, and resist the temptation to pile logs, bags or bin bags against the walls, which traps damp exactly where the timber is most vulnerable.
With a permeable base, water that gets under the shed drains away and air moves through. That combination is what keeps a timber floor sound for decades rather than years.
Sloping gardens
Few gardens are flat, and a shed base has to be.
For a gentle slope, dig into the high side rather than building up the low side. Cut-and-fill is fine for the last little bit, but material you have added is always less stable than ground you have not disturbed, so take more off the top than you put on the bottom.
On a steeper slope you will need a retained edge on the high side, and it is worth stepping back and checking whether the shed wants to be somewhere else. A level spot ten feet away is usually cheaper than a retaining structure.
Get it right first time
The one thing worth knowing: level and square, checked twice.
Almost every complaint about a shed comes back to the base not being flat. The door binds, the windows will not shut, the roof panels do not meet, and the building racks slowly out of shape.
Screed the blinding layer properly, check it with a straight edge in both directions and diagonally, and check the diagonals of your marked-out area match before you lay a single grid. Ten minutes with a spirit level and a tape saves a decade of a door that never quite closes, and unlike everything else on this list it cannot be fixed once the shed is up.
Ask our engineer
Questions about depths, base sizing, sloping ground or which system fits your building? Ask below, or get in touch directly.
Common Questions
Is a grid base as good as a concrete shed base?
For a garden building, better in most respects. Confined stone gives a firm level platform that spreads load across the whole footprint, and unlike concrete it stays fully permeable so rain drains through rather than pooling round the building and keeping the timber wet.
There is no mixing, no formwork, no curing time and no permanent structure left behind if the shed goes.
How deep do I need to dig for a shed base?
Around 110mm to 140mm in total for a typical garden shed, made up of 75mm to 100mm of compacted MOT sub-base plus the grid depth. Larger workshops or heavy contents need more sub-base.
It is a shallow dig, which matters when the spoil has to be carried through the house to get out of the garden.
How big should a shed base be?
Larger than the shed footprint by at least 100mm on every side. A shed roof throws water off its edges, and if the base stops at the footprint that water lands on soil and splashes back against the boards. Extending the base means runoff lands on free-draining stone instead.
Take it out further still on the door side, since that becomes the threshold you stand on.
What size gravel should I use for a shed base?
A 6mm to 14mm graded blend, angular and clean. A blend packs tighter than a single size because the smaller stone fills the gaps between the larger, and that density is what gives a flat stable platform.
Avoid rounded pea shingle, which rolls rather than interlocking, and anything carrying fines, which binds the surface and stops it draining.
Which grid depth do I need for a shed?
The 30mm grid suits most garden sheds: the shallowest dig, the least stone and the least spoil. Use 40mm for larger workshops, heavy contents, or where a wheelbarrow or mower route runs up to the base.
Use 50mm only where a vehicle will drive onto it, such as a garage-style building.
Do I still need bearers under the shed?
Yes. Set the building on bearers rather than directly on the base so there is an air gap under the floor. Rot in a shed floor almost always starts underneath, and it starts because moisture has nowhere to go.
A permeable base drains water away and bearers let air move through, which is the combination that keeps a timber floor sound.
Can I build a shed base on a slope?
Yes. For a gentle slope, dig into the high side rather than building up the low side, since material you have added is always less stable than ground you have not disturbed.
On a steeper slope you will need a retained edge on the high side, and it is worth checking whether a level spot a few feet away would be cheaper than a retaining structure.
How long does a shed base take to lay?
An afternoon for a typical garden shed, working alone. The grids push together by hand with no tools or fixings, and the base is usable immediately: there is no curing time, so the shed can go up the same day.
Most of the work is the digging.
Do I need planning permission for a shed base?
Garden buildings are usually permitted development subject to size, height and position limits, and a permeable base does not add to surface water run-off in the way an impermeable slab does.
Rules differ across the UK and are tighter for listed properties and conservation areas, so check with your local planning authority if you are unsure.
Can I put a grid base over an existing slab or paving?
Yes, provided the existing surface is sound and water has somewhere to go. Fill any holes, check your finished levels, and use the shallowest grid to keep the build-up down.
If the slab is badly broken or holds water, it is usually better to lift it, since a base that cannot drain gives up the main advantage of the system.
Ask our engineer
Questions about depths, sub-base, edging or which system fits your project? Ask below.
