The Brew Cabin

Posted: **Wed May 24, 2017 9:16 pm**

I am laying a patio partially within the RPA of a TPO tree (upon application the LA didnâ€™t want to know!)
In compliance with Arboricultural Practice Note 12 (APN12) and BS5837 the layers are as follows,
starting from the ground up:
Ground
Geo textile
Geocell (or similar) cellular root protection system in filled with aggregate.
Geo textile
Sharpe sand.
Pavers.
The infill for the Geocell is specified as angular sub base aggregate. However angular aggregate has sharp edges which could puncture the overlaying Geo textile thereby allowing the sand to wash through. How can this be resolved? Two layers of Geo textile?
Any advice would be much appreciated.

Roy

Posted: **Thu May 25, 2017 7:18 am**

Think this is one for the soft lanscapers. But if i would say if that is what they want to comply, then i would go with their advice, must be a sound reasoning behind it. I wouldn't worry about piercing the liner it is tough gear and sand loss would be minimal.

Posted: **Sat May 27, 2017 1:20 pm**

If you have the correct grade of geo-textile, its puncture resistance should be more than adequate for coping with a Type 3 sub-base aggregate.

Further, there are geo-cell systems that have a geo-textile bonded to the base and the best of these are rated syitable for use with a Type 3 agg.

Pitifully sparse specification for the actual paving layers. "Sharp Sand" is not sufficiently specific for such an allegedly detailed document, and then to have simple "Pavers" with no mention of joint width, jointing medium or permeability coefficient is pretty bloody shoddy, IMO.

The Brew Cabin

Problem complying with apn12