The office buildings in the NCC Herrjärva K11K12 development project, which have a BREEAM "excellent" sustainability certification, were part of the complex's redevelopment project to dismantle NCC's old headquarters and build a new one in its place, in accordance with the CEEQUAL v.5.2 sustainability certification. NCC, in order to meet CEEQUAL requirements and accelerate construction progress, had the old headquarters demolished ahead of schedule, allowing access to pipelines that needed to be relocated. This allowed construction work to be carried out in a single phase with no downtime. The roofs of the office buildings were covered with herbaceous plants and sedums to meet local requirements for rainwater management. To reduce the project's carbon footprint and save on physical resources, HVO fuel was used in part of the contract. Existing concrete structures were recycled and utilized, allowing less crushed stone to be purchased and fewer new KC columns to be installed, as the old ones could be reused.