Dear All,
I´m working on a major renovation project.
All the external concrete walls, roofs and pillar should be maintained but the insulation layer above the concrete will be changed with the better quality. Also, the inside of the external walls will be painted afresh.

In that case, how can I count the reused areas of the external wall? Does that mean I have 100% reuse of the external walls and roofs?

I´m very grateful for your help.

Best regards,