TPO tree root protection

[Minotaur]

I have recently started to do some work for a local business, they have several large Oaks & Beeches with TPO's.

They have appplied to the LPA for permission to lay some type one to a large area of rough ground for extra parking. They allowed a 2.5mx2.5m area around one of the trees but the LPA have come back and asked for some Anti compaction mats to protect the tree roots.

 

So question, how far out from the base of the tree should the mats be layed, at what depth and where can you get them, price??

 

Many thanks

 

Chris

[Jesse]

I have recently started to do some work for a local business, they have several large Oaks & Beeches with TPO's.

They have appplied to the LPA for permission to lay some type one to a large area of rough ground for extra parking. They allowed a 2.5mx2.5m area around one of the trees but the LPA have come back and asked for some Anti compaction mats to protect the tree roots.

 

So question, how far out from the base of the tree should the mats be layed, at what depth and where can you get them, price??

 

Many thanks

 

Chris

 

I'd be guessing at this point that they are referring to a Geo web type system, which can be laid within the RPA of a tree other than that its 12xstem diameter if its 2005 bs regs, which i think it will still be on the application form , not sure if the new forms have been updated yet.

[Paul Jenks]

You'll need to look at the 5837:2012 version. They have the specs for ground protection for pedestrian, light machinary and heavy.

If the parking is to be semi-permanent then type one will do no end of harm. You'd do better specifying CellWeb with a granular fill over membrane. Google CellWeb/Geosynthetics. This will ensure gas and moisture porosity.

[daltontrees]

 

So question, how far out from the base of the tree should the mats be layed, at what depth and where can you get them, price??

 

Chris

 

I would imagine the LPA wants the mats everywhere the car parking is proposed AND that lies withing the tree Root Protection Areas, see BS5837 for RPA extents but someone has already mentioned the 12 x stem diameter rule-of-thumb

Best if mats laid on existing surface with minimal preliminary excavation and levelling. If the trees are worthy, the LPA would be within its rights to consider refusing the application if excavation close to the tree is proposed before putting type 1 down. Edging may be needed to contain the type 1.

I don't know how much it costs but as an alternative to excavating and disposing of material it might well be cost-effective to use CellWeb.

[oslac]

Type 1 should not be used within the RPA of a retained tree. It contains fines and will create a non permeable surface. As mentioned already; within the RPA a cellweb or similar layer should be pinned down over a geotextile and infilled with non-fines material such as 20-40mm crushed stone. Lay geotextile over this and lay the wearing course. Retain edges with 50mm thick wood edging staked or railway sleepers pinned to the ground. All of the above must employ no-dig methodology.

 

I don't have a copy of the latest BS with me (being Sunday and trying not to be too anal) but I think the BS limits the extent of any new surface (permeable or not) to 20% of the available RPA.

 

I am very suprised . . . no I am not . . . that any council tree officer would allow Type 1 within the RPA or extend the car park area to more than 20% without requiring full methodology, however, this seems to be permitted development and all you need do is not damage any part of the protected tree and I doubt the council could prove that you have damaged the tree by surfacing the RPA with anything you like.

.

[Minotaur]

Thanks for the replies. I am going to go along and speak to the Tree Officer myself, will report back

[sloth]

Thanks for the replies. I am going to go along and speak to the Tree Officer myself, will report back

 

Anything to report?