Hi All,

We are working on a major renovation of an office project (shell only) and aim to certify it under the LEED v4.1 BD&C CS scheme.

The project site is 2,000 m², with a building footprint of 900 m².

I have a question regarding Rainwater Management - Option 2: Natural Land Cover Conditions, and I would appreciate your guidance.

The LEED v4.1 guidelines for Option 2 state that "we should calculate the difference between the projected runoff volume under the proposed design conditions and the runoff volume under natural land cover conditions that existed prior to any disturbance."

Could you clarify what is meant by "natural land cover conditions prior to any disturbance"? Does this refer to the conditions before the existing building was constructed? I ask because the runoff volume will remain the same before and after the renovation, as the building footprint is unchanged.

Many thanks