BS5837

[roscoe1982]

Morning Chaps can anyone tell if there is any mention to the acceptable incursion into the RPA (%) in the BS5837 or anywhere else I can find a mention of a recommended level?

 

hit me back

[Anno]

Not in the new BS 5837 - 20% has gone, although most folk still try it to get around incursion...

[roscoe1982]

is there limit to the incursion though even when using minimal dig solutions, etc.

[Paul Barton]

7 hours ago, roscoe1982 said:

is there limit to the incursion though even when using minimal dig solutions, etc.

 7.4.2.3 New permanent hard surfacing should not exceed 20% of any existing

unsurfaced ground within the RPA.

 

However, I would say that if you can justify more then have a go.  Justifying it is not easy though...you are likely to need details on soil structure and a carefully specced installation of the 'no-dig' solution.  Some tree officers accept it and some don't.

[daltontrees]

17 hours ago, roscoe1982 said:

is there limit to the incursion though even when using minimal dig solutions, etc.

The BS is not the law, it is guuidance. You haven't said whether you are trying to get planning permission. If you are, the Council will probably want strict compliance with BS5837. If so, and permission was refused because of 'incursion' and no justification is given for the incursion, then an appeal would probably fail.

 

5837 says -

The default position should be that structures are located outside the RPAs of trees to be retained. However, where there is an overriding justification for construction within the RPA, technical solutions might be available that prevent damage to the tree.

If operations within the RPA are proposed, the project arboriculturist should  demonstrate that the tree(s) can remain viable and that the area lost to encroachment can be compensated for elsewhere, contiguous with its RPA, and propose a series of mitigation measures to improve the soil environment that is used by the tree for growth.

There is no magic number.

I hope that answers the question, although I was hesitant at first for rewarding your use of the ghastly and insistent phrase 'hit me back'. Next time it should at least be hit me back please.

[roscoe1982]

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I understand that BS isn't law, rather Recommendation. All the relevant tree protection plans were submitted with the use of a minimum dig solution, cellular confinement system, however they have said that even with this, they have said that the scheme will place undue pressure and threaten the trees. this is going to planning inspectorate hearing in October. it seems a thin argument for refusal but  there are other reasons for the refusal several, in fact. the incursion isn't near 20% for all trees but 1.  

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