Include the entire roof structure and the absorbed water in the assessment.
The complete structure counts
Een green roof consists of more than vegetation. Consider substrate, drainage, protective layers and water that may be present in the system. Ask the supplier for the data relevant to the constructive assessment.
Coordinate roof and design
Discuss the existing roof structure and the new one load and the drain. Maintenance, installations and local additional loads can also play a role. First have it assessed whether the existing construction is suitable or needs to be adjusted.
Request details of the entire roof structure
A green roof involves more components than the visible plants. Including substrate, water storage layers, drainage and any ballast contribute to the weight. Ask the supplier for the relevant weights for the intended conditions, including water absorption. Also include walkways, edges and local features. An average weight of the plant layer alone does not provide a complete picture for the constructive assessment.
Check the combination with existing roof functions
A roof can already support installations, solar panels or storage. Have existing and new components included in the same load overview. Drainage and maintenance access must also be coordinated with the architectural design. Discuss future expansions directly. A constructive assessment based on a specific layout does not automatically apply to a later changed distribution of planters, ballast or installations.
Your preparation in four steps
- Product specification of the complete structure
- Weights according to supplier
- Roof and construction drawings
- Drainage plan and maintenance access
Frequently asked questions on this topic
When do I have my existing flat roof assessed?
In the event of a planned change in weight, use or construction, a targeted assessment is useful. Consider extra insulation, installations, solar panels, a green roof or an opening. Describe the existing and desired structure and indicate known deformations.
Why do drainage and construction belong to the same consultation?
Water that accumulates on a roof can cause additional strain. Drainage and any emergency facilities must therefore be coordinated with the architectural and structural design. The suitable solution depends on the complete roof structure and geometry.
View the associated structural calculation, create your preparation list or take the guides and checklists along to the consultation.