Græsarealer til events og festivaler
Underlag der overlever opbygning, event og nedtagning
Events ødelægger ikke marker. Opbygningsugen gør. IBRAN-gitre armerer underlaget der, hvor det tunge arbejde foregår, så pladsen håndterer trafikken og arealet vender tilbage til normalen bagefter.
Hvorfor armering er afgørende her
Spørg nogen, der driver et eventareal, hvad der ødelagde det, og svaret er sjældent publikum. Det er de to uger på hver side: sættevogne med sceneudstyr, teleskoplæssere frem og tilbage, generatorvogne, mandskabsvogne – alt sammen på blød jord i hvad vejret nu byder på.
Fodtrafik giver sin egen skade på koncentrerede steder: ved porte, foran scener, langs de naturlige ganglinjer mellem arenaer – men folk spreder sig, og græs regenererer. Køretøjer spreder sig ikke. De følger den samme rute til det samme område, drejer på det samme punkt, og er underlaget vådt, skærer de ned i det, og så er skaden sket.
Armering af det underlag ændrer hele eventets økonomi. Ruter og opholdsarealer forbliver brugbare i dårligt vejr, så opbygningen ikke går i stå. Arealet bliver ikke pløjet op, så retablering er billigere eller unødvendig. Og underlaget er klar til næste event frem for at skulle have et år til at komme sig.
Hvor dette fungerer godt
- Køreruter og transportveje på tværs af arealet
- Produktions- og artistområder
- Fodaftryk for scener, telte og konstruktioner
- Opstillingspladser for generatorer, mandskabsvogne og containere
- Indgangsslusser og flaskehalse
- Bar-, madbod- og højtrafikerede zoner
- Overløbsparkering og adgang til campingområder
- Ruter for rednings- og ambulancekøretøjer
Overblik
| Bærelag | 150-250mm åbengraderet bærelagsgrus til køreruter. Mindre ved udelukkende fodtrafik |
| Fyld | Sandbaseret vækstjord til græs, eller 6-20mm graderet stenblandning til opholdsarealer og opstillingspladser |
| Typisk belastning | Sættevogne, teleskoplæssere, kraner, containere, generatorer, publikum |
| Udseende | Græsfyld giver et areal, der stadig fremstår som en mark mellem events |
| Anvendelighed | Brugbar i vådt vejr, så opbygning og nedtagning ikke er vejrafhængig |
| Permeabilitet | Fuldt permeabel. Vand afledes frem for at stå foran scenen |
| Designlevetid | 25 år, forudsat dokumenteret udførelse |
| Materiale | 100% genanvendt polypropylen, fremstillet i EU |
Permanent armering eller midlertidig køreplade?
De fleste eventsites lejer køreplader, og til et enkeltstående event på et ukendt areal er det det rigtige svar. For et areal, der huser events år efter år, ændrer regnestykket sig.
Køreplader er en tilbagevendende udgift med tilbagevendende arbejdstimer: de ankommer, lægges ud, samles op, køres væk, og næste år betaler du igen. De skal også lægges ud, inden vejret vender, hvilket betyder, at du forpligter dig tidligt, uanset om du har brug for dem eller ej.
Permanent armering er én installation, der bare er der. Græsset vokser op igennem det, marken ser ud som en mark, og hvert efterfølgende event bruger et underlag, der allerede er forberedt. På de ruter og opholdsarealer, der bruges hver eneste gang, er det som regel den billigere løsning inden for få sæsoner – og det fjerner en logistikopgave fra hver opbygning.
Den fornuftige tilgang på de fleste arealer er begge dele: permanent armering på den faste infrastruktur, der aldrig flyttes, og køreplader til det, der skifter med hvert events layout.
Hvilken gitterdybde?
Dybdetallet på et gitter er en beslutning om, hvor dybt det inddæmmede lag er – og på et eventareal følger det opbygningstrafikken snarere end selve eventet.
- IBRAN®-X50 er vores anbefaling til køreruter, opholdsarealer og konstruktionsfodaftryk. Opbygningstrafikken er tung, den drejer, og den ankommer uanset underlagets tilstand.
- IBRAN®-X40 til lettere ruter, overløbsparkering og blandede fodgænger- og lette køretøjsarealer.
- IBRAN®-X30 til fodgængerarealer, gangstier og campingarealer, hvor opbygningshøjden skal holdes lav.
Specificer efter det tungeste køretøj i opbygningsprogrammet, ikke gennemsnittet. På de fleste arealer er det en lastvogn med sættevogn eller en teleskoplæsser – og begge drejer.
Valg af fyldmateriale
Til arealer, der skal forblive grønne mellem events, bruges en sandbaseret vækstjord fyldt i niveau med celletoppen samt en slidstærk brugsplænegræsblanding. Marken fremstår som græsareal eller parkland i halvtreds uger om året og bærer eventet i de resterende to.
Til opholdsarealer, opstillingspladser og permanente transportruter bruges en 6-20mm graderet stenblandning, kantet og ren. En blandning pakker tættere end én enkelt størrelse, fordi den mindre sten udfylder mellemrummene mellem den større – og en fuldt understøttet celle fører lasten gennem stenen frem for gennem plasten. Det giver en fast, forudsigelig overflade til containere, generatorer og stablet udstyr.
Hvor en stenbelægning ville se forkert ud, er det værd at huske, at den kan overdækkes: en stenfyldt rute under et tyndt tørv- eller måttelag under eventet giver dig den bærende overflade og det udseende, du ønsker på dagen.
How it goes in
- Map the fixed infrastructure first. Every site has routes, gates and compounds that are in the same place every year. Those are what to reinforce; the rest changes with each layout.
- Set out and establish falls. Event fields are often the flattest land available, which means water has nowhere obvious to go. Decide where it goes before you build.
- Strip turf and topsoil to a firm formation, removing soft spots rather than building over them.
- Lay a woven geotextile across the formation, lapping joins by at least 300mm. On agricultural ground this is structural, stopping the sub-base punching down into soft subsoil.
- Lay and compact an open-graded sub-base in 50mm layers, to a depth set by the heaviest vehicle in the build schedule.
- Blind with a thin levelling layer and screed flat.
- Push-fit the grids together, staggering the joints, and cut around gateposts, services and existing drainage.
- Restrain the edges, particularly along routes, where vehicles will otherwise clip the edge and drag the outer grids sideways.
- Fill the cells level with the cell tops and brush in. Seed or turf grass areas and allow a full growing season before the first event where you can.
Full step-by-step detail is in our grass grid installation guide.
Planning the build, not the event
The single most useful exercise is to walk the site with the build schedule rather than the event plan.
Where does the first artic go, and what does it drive over to get there? Where does the telehandler spend the week? Where do the cabins land, and what route did they come in on? Which gate takes every delivery, and where does a lorry turn round when it has unloaded?
Those answers give you a map of the ground that takes real punishment, and it is usually a surprisingly small proportion of the site. Reinforcing it costs a fraction of surfacing broadly and fixes most of the damage, because the damage is concentrated exactly where the heavy plant repeats the same movements.
Add the emergency and medical routes to that map. Those have to work regardless of weather, and unlike the rest of the schedule you do not get to reschedule them.
Crowd areas and pinch points
Foot traffic does not rut ground the way vehicles do, but it destroys grass where it concentrates: entrance gates, the front of a stage, bar frontages, the route between two arenas, and the toilets.
Those areas turn to mud through sheer repetition, and once they do they become both a welfare problem and a reputational one, since mud is what ends up in the photographs.
Reinforcement keeps the ground firm and free-draining under crowd loading, so a wet weekend produces a damp field rather than a quagmire. For sites that market themselves on comfort, that is worth more than the construction cost.
Handing the land back
Many event fields are rented, borrowed or dual-purpose: grazing, sports pitch, parkland, farmland. The obligation to return them in good condition is often the binding constraint on whether an event can happen at all.
A grass-filled grid is invisible once established, so the land continues in its normal use between events. It stays fully permeable, so it does not change drainage on the holding. And because the ground is not churned, reinstatement after each event is minor rather than a major earthworks job.
If you are negotiating a multi-year agreement with a landowner, the ability to say the ground will not be damaged is a considerably stronger position than promising to repair it afterwards.
Get it right first time
The one thing worth knowing: build for the wettest version of your build week.
Every event site is specified against a reasonable weather assumption, and then one year it rains for the entire build. That is the week that decides whether the ground survives, because a heavy vehicle on saturated ground does more damage in one pass than a hundred passes in the dry.
Specify the routes and compounds for the bad year rather than the average one. It costs a little more once, and it removes the scenario where the build stalls, the ground is destroyed, and the reinstatement bill arrives on top of an event that already went badly.
Ask our engineer
Questions about depths, which areas to reinforce, or how this compares to trackway hire? Ask below, or get in touch directly.
Design your surface
Set out the area, choose a grid and an infill, and see the finished surface. The schedule and the specification follow.
Permeable surface specification
Schedule
Assumptions
Specification
Common Questions
What actually damages an event field?
Rarely the crowd. It is the fortnight either side: artics delivering staging, telehandlers running back and forth, generator trucks and welfare units, all on soft ground in whatever weather turns up.
People spread out and grass recovers, but vehicles follow the same route to the same compound and turn at the same point, and on wet ground that is what does the lasting damage.
Is permanent reinforcement better than hiring trackway?
For a one-off in an unfamiliar field, trackway is the right answer. For a site hosting events year after year, permanent reinforcement on the routes and compounds that never move is usually cheaper within a few seasons and removes a logistics job from every build.
Most sites end up doing both: permanent reinforcement on fixed infrastructure, trackway for whatever changes with each layout.
Which areas of a site should be reinforced?
Walk the site with the build schedule rather than the event plan. Where does the first artic go and what does it drive over? Where does the telehandler spend the week? Which gate takes every delivery and where does a lorry turn round?
That map is usually a surprisingly small proportion of the site, and it is where the damage concentrates. Add the emergency and medical routes, because those have to work regardless of weather.
Which grid depth does an event site need?
The 50mm grid for vehicle routes, compounds and structure standings, because build traffic is heavy, it turns, and it arrives whatever the ground conditions. The 40mm for lighter routes, overflow parking and mixed pedestrian and light vehicle areas. The 30mm for pedestrian areas and camping ground where the build-up needs to stay shallow.
Specify against the heaviest vehicle in the build schedule, not the average one.
Will the field still look like a field between events?
With a grass fill, yes. Grass grows up over the cell tops and the reinforcement is invisible once established, so the land continues in its normal use as grazing, sports pitch or parkland.
Mowers pass straight over because the cell tops sit below the growing crown.
Does reinforcement help with crowd areas and mud?
Yes. Foot traffic destroys grass where it concentrates: entrance gates, the front of a stage, bar frontages, routes between arenas and the toilets.
Reinforcement keeps those areas firm and free-draining under crowd loading, so a wet weekend produces a damp field rather than a quagmire. For sites that market themselves on comfort, that is often worth more than the construction cost.
What should event site grids be filled with?
A sand-dominant rootzone with a hard-wearing amenity seed mix for areas that must stay green between events. A 6-20mm angular graded blend for compounds, standings and permanent haul routes, where a firm predictable surface matters more than appearance.
Where a stone route needs to look right on the day, it can be topped with turf or matting for the event.
How long before a new installation can host an event?
For grass areas, allow a full growing season before the first event where the programme permits, because the surface is only as strong as the root structure holding the rootzone together.
Stone-filled compounds and routes are usable as soon as they are laid and filled. Where time is short, use turf rather than seed and phase the areas that establish first.
Does it help when the land is rented or dual-purpose?
Considerably. Many event fields are grazing, sports pitch or farmland, and the obligation to return them in good condition often decides whether an event can happen at all.
Because the ground is not churned, reinstatement after each event is minor rather than a major earthworks job, and being able to tell a landowner the ground will not be damaged is a stronger position than promising to repair it.
Will it work if the build week is wet?
That is the case to specify for. A heavy vehicle on saturated ground does more damage in one pass than a hundred passes in the dry, so build the routes and compounds for the bad year rather than the average one.
A reinforced, fully permeable surface stays usable when the surrounding ground does not, which keeps the build on schedule rather than stalling it.
Ask our engineer
Questions about depths, sub-base, edging or which system fits your project? Ask below.
