Full Planning Granted - Non material amendment for a basement?

[Ceefer]

Hi,

 

We have full planning and we have been obtaining quotes for the build. We are looking at ICF and the plot is on a slope, with the lower area being flood zone 2. Two of the companies have asked why we did not go for a basement as the below would not be a problem.

 

We did have an FRA as part of the planning app and it said : 

 

RECOMMENDATIONS
This report assesses that the development is located in Flood Zone 2 and 3. Therefore, as the site has a high risk of flooding. A number of recommendations can be made which may lower the risk or consequence of flooding. The key recommendations of this report are:
 
EXECUTIVE SUMMARY
  
A raised threshold should be included within the design, consideration must be given to raise above 15.71m AOD to mitigate against residual risk e.g. surface water routing through the site and uncertainty with the EA modelled flood levels.
Avoid the construction of basements due to the proximity of the river unless a suitable design has been met to passively exclude ground water, to the satisfaction of the EA.
Sustainable Urban Drainage Systems (SUDs) should be considered for incorporation into the design where feasible and the final proposal should ensure no increase in surface water runoff. Due to risk residents and those responsible for the development should be encouraged to sign up to the EA’s FloodLine Service so they are made aware of river levels.
 

 

How would we find out if this would be possible? Could we submit a Planning - Non material amendment for a basement? If it's rejected would we lose the full planning? 

 

Thank you,

 

 

Edited April 22, 2019 by Ceefer

[the_r_sole]

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Edited September 26, 2019 by the_r_sole

[Mr Punter]

Basements are fairly high risk and you need to consider ground conditions, safe excavation, ventilation, daylighting, retaining walls and waterproofing.  Given the FRA I am not sure why you would bother. You would need a minor material amendment application for this.  You could only use the basement for non-habitable purposes - cinema, gym , store etc.

[Sue B]

After hearing other things that the planning authorities have said would be a new full application rather than a NMA, I can’t imagine adding an additional space, contrary to the FRA that you have provided would be acceptable.  Basements are not cheap.  If you really want a basement, go for it, but you will now need to disprove your own FRA.  

 

[Ceefer]

Thank you all for the information, I think I will leave it and put a separate garage up!