ᐅ Flat Roof Waterproofing for Carport, External Wall Insulation System with Render? Alternatives?

Hello everyone,

I need your experience on this. We currently have quotes for the waterproofing of a flat roof, insulation, and gravel for the terrace (including the entrance area, so an outdoor seating area) as well as for the carport.

I’m wondering if there might be a cheaper option since both are not directly part of the house. The setup is: flat roof (concrete), insulation, waterproofing, gravel. Price per square meter: 180 € including VAT. I don't think I actually need to insulate the carport since it’s open, right? I see many concrete carports in new housing developments from builders that probably wouldn’t spend around 7,500 € just for the roof structure and concrete.

For the external thermal insulation composite system with mineral wool, plaster, and painting, they’re asking 140 € including VAT per square meter. Is that a realistic price, or what have you paid?

Thanks for your feedback!