Garage roof heat insulation - roof is sealed with tar paper

From our offer at the beginning of 2017:

Substrate made of recycled clay bricks, with substrate compost and fibrous materials, frost and flashfire resistant,
bulk density at maximum water absorption 1400kg/m3
Delivery and application 193€/m3
he calculated with 1m3 for 10sqm
plus
Sedum cuttings at least 4 species
application, rolling, first watering 6.60€/sqm

Attention everything net and of course the costs for root barrier and raised drainage piece are still missing here

EXTENSIVE ROOF GREENING, laying of root protection foil 0.4 mm, separating fleece as slurry protection; application of soil substrate, approx. 8 cm thick; application of a 15 cm wide gravel strip; planting with sedum species, approx. 8-10 pieces per m² Total price per sqm €42.50 Zapf offers it at a similar price