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Appeal Decision 99 - Certificate of Lawful Development.

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February 2010 - Code a00099


Summary of Case (appeal dismissed): 


The property is a house and the application related to an enforcement notice against the installation of a hard surface  


The first key issue was whether the hard surface is contrary to Class F, part F.1, which states the following:. 


“F.1 Development is permitted by Class F subject to the condition that where— 


(a) the hard surface would be situated on land between a wall forming the principal elevation of the dwellinghouse and a highway, and  

(b) the area of ground covered by the hard surface, or the area of hard surface replaced, would exceed 5 square metres,  


either the hard surface shall be made of porous materials, or provision shall be made to direct run-off water from the hard surface to a permeable or porous area or surface within the curtilage of the dwellinghouse.” 


The Inspector stated the following: 


“I arranged for another test to be undertaken during the hearing so that I could see for myself what happened. However, before describing that, it is worth noting that the GPDO does not define what is meant by ‘porous’. I have therefore had regard to its normal dictionary meaning – ie permitting the movement of fluids or gases by way of pores or other cavities. I have also taken into account advice in the document entitled ‘Guidance on the permeable surfacing of front gardens’ [‘the Guidance’] published by Communities and Local Government. This had been referred to by the Council in their pre-hearing statement and I made a copy available to the appellant at the hearing.  


During the hearing, Mr Najim, in response to my questions, advised that the subbase for the hardstanding comprises 200mm of Type 1 hardcore, which had been compacted very thoroughly. The Guidance describes Type 1 hardcore as impermeable as it contains a lot of fine material (such as sand and silt) that prevents water passing through it easily. It goes on to advise that for permeable and porous driveways different materials are required that allow water to pass through and which can also store water for a while if it cannot soak into the ground as fast as the rain falls. In short, it seems that to be porous a sub-base needs to be relatively coarse with spaces that allow water to penetrate it.  


I made sure that Mr Najim was aware of what the Guidance says on this matter, but he did not retract his statement that the sub-base is Type 1 hardcore. In any event, use of Type 1 is consistent with what could be observed during my visit where blocks had been removed and is what the quotation for the drive specified. I note also that the contractor did not guarantee that the drive would be porous; has no obvious qualifications in laying porous drives; and seems to have been chosen largely because he had gone round the area seeking business. Moreover, in addition to all this, when the porosity test was carried out water collected in the holes where blocks had been removed and took several minutes to drain away. The Guidance advises that water poured onto a permeable sub-base will soak in straight away within a small area. 


The porosity test also demonstrated that when water was sprayed onto the drive some of it ran off towards the highway. That is not surprising given that much of the drive slopes quite steeply down towards the road, but even on the flatter areas there was evidence after two minutes of water puddling and starting to flow away. Furthermore, the water tended to follow the gaps. This suggests that, contrary to the appellant’s contention, the blocks do not themselves readily absorb water whilst the gaps between them are not wide enough and/or are filled with a material that is not sufficiently coarse to allow water to sink in quickly. Certainly neither the gaps between the blocks nor the ‘nibs’ on them seemed to me to be appreciably larger than has traditionally been the case. 


Be that as it may, if, as seems to be agreed, the sub-base is impermeable Type 1 hardcore the nature of the blocks, the size of the gaps between them and what is in those gaps is all of limited consequence as the sub-base itself will prevent water draining through. Taking all this into account, I conclude that as a matter of fact and degree the surface that has been laid is not porous. Accordingly the works alleged in the notice have taken place. The ground B appeal therefore fails. 


In addition, as the surface is not porous and as it is agreed that it does not currently drain to a soakaway or any other permeable land within the curtilage of no. 115 it does not comply with the limitations specified in the GPDO. The works do not therefore constitute permitted development and planning permission is required for them. Nothing in the Council’s letter of 11 May 2009 can, or does, alter this. The ground C appeal therefore fails also.” 


Main Conclusions: 


·       This appeal decision provides an example of where it was considered that a hard surface was not porous, and contrary to condition F.1.
[Relevant to: F.1].


Links to the “Appeal Decision Notice” and other associated documents (e.g. drawings, etc): 


·       Appeal Decision Notice: 




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