9 Sep 2010 by mackay
Dear All
I've always believed that in new sportsturf constructions there is a legal requirement for the top 50mm of rootzone to be screened to 4mm, however, I don't know where I got this from and haven't been able to find much backing this idea up.
Am I right in this belief, and could anyone point me in the right direction with regards to more info?
9 Sep 2010 by vid
Dont think so Andy - I would almost certainly think that is a local specification requirement. It would be a bit on the overkill side as far as risk assessment goes!! I have been part of playing field construction over the last few years and you could add a '0' to the material size. It would be inhibitively expensive to have to grade soil down that far.
I could well imagine a 10mm screened soil being required but I certainly have not heard of legal requirements for it, but 4mm I cant see that as even being possible - imagine the waste.
9 Sep 2010 by mackay
All rootzone I use is screened to 4mm, and am certain that all the recent 1st Class cricket outfields new outfields will have 4mm screened material in top part of rootzone, ditto golf green constructions, top flight football pitches etc etc but take I your point.
Mr M, info as far as I am aware from this side of the fence, I am sure comment can be added by producers.
Rootzone, is produced in general with a sport sand, which by its nature would be only a very small percentage over 2mm and only allowed (if recognised sport sand) very little between 2 and 4mm and certainly would not (should not) have anything over 4mm which is more to do with production of sands and the other products produced out of individual quarries. The soil/organic material to be added to this in whatever percentage would generally be screened soil, peat, greenwaste or fensoil type products and generally these would/should all be produced to reasonably tight tolerances, invariably the mixing process involves a screening plant which actually mixes the materials together rather than separates which every other industry uses screens for, but takes off oversized particles or motts of material (balls to the rest of you, not being rude, small round lumps of material formed by the belts and material movements), again it is recognised that a 4 to 6mm screen produces the most acceptable 'mix' and product.
In terms of Specification or legal requirement on the top 50mm then it is certainly news to me. A sport surface is more about performance and available budget. There is absolutely no technical reason why a soil with clod and stone content over 10mm would not perform adequately if that is what is specified as the growing medium, surface safety issues are another matter and if sharp stones were present on the surface then this may give some cause for litigation should someone cut their leg open.
On some of the worst stone content sites the only answer may be to clean off over 16-20mm with a picker or burier, grade and dress over with 10-20mm of sand or rootzone, but again this may only be possible if the money is allowed for in budgeting, which often it isn't. Cleaning or screening soil below 20mm does more structural harm than good IMHO.
Taking too many stones out of some soils actually destroys their structure causing far more problems than it solves..
However if you were importing a true Rootzone as a surface to meet a specification and the top 50mm did not meet that requirement then its more about a cr4p source or job being done than legals.
The vast majority of new surfaces below the top 10% of facilities can only dream of either affording a decent Rootzone and certainly would not have the ability or manpower to keep it watered in the summer months.
Thoughts anyways.......
The SAPCA Code of Practice for Natural Sports Turf states IMPORTED TOPSOIL should be to BS 3882 : 2007 or INSITU top 100mm should both have no stone content above 16mm.
Register free at sapca.org.uk to view this and other info.
Plastic.... it's The End I tell you... THE END!!!!
10 Sep 2010 by vid
Spot on Barry - budget construction of large sports areas (eg academies and other government school projects) in my experience are made out of imported and often ungraded topsoil. this is then 'stone buried' to produce a reasonably stone free surface rootzone. Dont blame the constructor as the contractors are on a cut throat price and are producing as good a surface as they can with inferior material. High class facilities will generally use at least 50mm of graded topsoil or blended rootzone material.........always comes down to money availability in the end
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