In June 2010 Fineturf commenced work on a project for Balfour Beatty Construction at the City of Lincoln School Academy. The contract was to construct a new 60,000m2 playing field on a land fill site situated next to the school, which was also undergoing major renovations. The finished playing field was to consist of, 3 football pitches, a five-a-side football pitch, a football training grid, 2 rugby pitches, 2 hockey pitches, an artificial cricket oval and an athletics area.
In summary, the work included the excavation of two topsoil layers to be stockpiled, a full drainage system, respreading of stockpiled topsoil, importation of sports sand, laser levelled ground preparation, sports turf and sports seed surface installation and a one year maintenance period.
The construction phase of the project was successfully completed during the period from June 2010 to August 2010.
Phase 1 Surface Removal
The first task was to remove the top 20mm of existing vegetation from the entire site. A Blec Combinator was used, which fraize mows the surface and transports the excavated material on a conveyor system directly into a tractor towed trailer. All arisings and green waste was recycled; approximately 1000m3.
Phase 2 Excavation of Topsoil Layers
A ‘loose tipping’ method was used to excavate the topsoil which required tracked excavators and low pressure tyre dumpers. This allowed both the upper and lower topsoil layers to be accurately removed to depths of 100mm and 200mm respectively.
The two topsoil layers were stockpiled separately to be reused at a later stage. The lower topsoil layer was of mixed grade but would provide a good growing medium and the upper topsoil layer was high quality and stone free.
The stockpiles were kept to one load high, avoiding compaction by dumpers and a possible build up of anaerobic conditions. A tracked excavator was used to regrade and firm the top and sides, sealing in dry soil and reducing rainfall infiltration.
J.C Balls, plant hire and excavation specialists, supplied additional plant and machinery to help with the earthworks phase of the project, which included the topsoil strip and stockpiling.
Phase 3 Drainage System and Sand Carpet
Using a 360 Excavator with power tilt attachments, 225mm deep v-trenches were dug into the formation layer at 8m centres. A 100mm diameter drainage pipe was laid in the trenches and they were backfilled with 6-10mm washed drainage gravel.
The nature of the existing soil and the sand carpet meant this spacing was more than adequate to provide an effective and efficient drainage system.
A 75mm sand carpet was then laid across the site which required 4,500m3 of sports sand. A Blec Laser Grader was used to accurately level the base. The sand carpet would increase the depth of the growing medium and act as a formal barrier to any contaminated soil remaining below the excavated depth of 300mm.
Phase 4 Topsoil Spreading
Firstly, 12,000m3 of the stockpiled lower layer top soil was load spread. Low pressure tyre dumpers carted the soil along a designated track and tipped in windrows to be levelled by bulldozers. This method avoided mixing topsoil with the sand base. This lower topsoil layer was then precision laser graded to give a surface tolerance of +/-25mm over a 3m straight edge and to a firmed depth of 200mm.
The upper topsoil layer was constructed from 6,000m3 of the previously excavated stone-free topsoil. This was respread and levelled using the same process and accuracy as the lower layer, ensuring the two didn’t mix. Laser grading was performed to a tolerance of +/-20mm over a 3m straight edge and to a firmed depth of 100mm.
Phase 5 Final Ground Preparation
The final ground preparation required a 25mm layer of sand over the area of the pitches. This sand was lightly ameliorated into the top 25mm of the upper topsoil layer. A 0:20:20 fertiliser was also ameliorated into the surface. A Blec Rotor Rake created a good level tilth ready for seeding and turfing.
Phase 6 Football Turf Installation
The first team football pitch was to be turfed using premium large roll football turf. Prior to this a 15:10:10 pre turf fertiliser was applied. A tractor and spike was used for transporting the rolls and a Tim Machine to lay them. Take a look at our how to lay big roll video.
Phase 7 Sports Seed Sowing
The remaining sports pitches were seeded using Limagrains MM60 winter sports mix. This is a fast germinating and hard wearing 100% rye grass mixture. The mixture is used at a number of premiership and championship football clubs with excellent performance results. The seed was drilled in transverse directions and applied at 60gm2.
The entire project took approximately 13 working weeks to complete and so far the germination results have been better than expected. We will continue to maintain and monitor the pitches for the next 12 months to ensure no problems arise. For more information on football pitch construction and sports pitch construction visit our main website.