Extending raised wooden deck into Root Protection Area

[Bobbyboo]

I am looking to extend my wooden patio deck by about 2m into my rear garden.

 

The existing decking is sitting on wooden posts bolted onto concrete trenches. There is a large TPO’d oak to the far side of the decking which has a 7m RPA. 

 

Extending the decking would cut into the RPA, but take up way less than 20%. The extension will require 3 or 4 new posts, 2 of which would be within the RPA about 5-6m from the tree. 
 

To minimise any impact, I plan on using ground screws. The decking is suspended 15-20cm above the ground and no removal of soil would be required (only a top layer of grass removed). There would be ample air circulation and otherwise no impact on the soil.

My understanding is that this would fall well within permitted development, and provided I don’t damage any roots when installing the ground screws, I am safe. 
 

Am I ok to proceed with this work, or do I need to notify the Tree Officer or submit an application (really do not want to!).

 

[Dreadnaught]

I have an RPA at my new build and had a Aboricultural Method Statement, etc. Your works sounds to me like the sort of thing that would be allowed in an RPA. I'd ask a friendly arboriculturalist in a quick phone call whether it requires pre-approval or not. 

 

My guess is you might be asked to have a qualified arboriculturalist "supervise" the insertion of the ground screws, with a mind to relocate them if they would hit a big root.

 

Are you on the radar of your local tree officer already?