Sustainable Homes

Sur1 - Default Cases

 

Category 4 of the CSH includes 'default cases' whereby the mandatory criteria of Sur 1 can be deemed to be met by default. The most common cases which we come across includes the following:

  • Where the man-made impermeable surface draining the watercourse / sewers has decreased or remained unchanged post development.

  • If the surface water from the site discharges rainwater directly to a tidal estuary or the sea.

  • If planning approval (covering the detailed drainage strategy for the site) has been granted prior to the Code requirement being set.

  • If a site is directly connected to existing infrastructure which pre-dates the Code requirement for the site.

By satisfying the Sur 1 mandatory requirements by default surface water run-off calculations are not required.

We offer a CSH Category 4 report, specifically tailored for sites where Sur1 is met by default for £520 + VAT - see our schedule.  A Flood Risk Assessment is still required in these cases.

With Sur 1 default cases you do not automatically get Sur 1 credits.  The  only way to then get the  Sur 1 credits is by achieving the following:

  • Ensuring no discharge from the site for rainfall depths up to 5mm

  • Ensuring the run-off from all the hard surfaces receives an appropriate level of treatment.

By their nature, default options 2 and 4 cannot achieve the credit criteria. We advise you on whether your proposed drainage system can achieve the credits. Contact our CSH team on 01824 702 220.