23/11/2025
illustrates the design and structural considerations for Roof Planters on buildings primarily focusing on the relationship between planting depth resulting vegetation and the associated structural load on the roof.
The diagram is divided into two main sections: a detailed sectional view of the planter components and a stepped elevation view demonstrating load requirements.
🏗️ DETAILED SECTIONAL VIEW
This top-left diagram shows the layer composition of a typical roof planter from the structure up to the vegetation.
* Concrete: The foundational structural layer of the roof slab.
* Slope Screed: A lightweight concrete layer placed on the structural slab to create a slope ensuring proper drainage.
* Anti-Root Membrane: A critical layer that prevents plant roots from penetrating and damaging the waterproof membrane and the structural concrete below.
* Drain Pipe: Located at the low point of the slope screed to collect and remove excess water.
* Gravel: A layer that provides sub-surface drainage allowing water to filter through and reach the drain pipes easily.
* Filter Fabric: Placed above the gravel to prevent the finer soil particles from washing down and clogging the drainage layer.
* Soil: The growing medium for the plants.
* Grates: Shown in the cross-section often used around drainage points or edges to manage overflow and provide access.
The vertical dimensions shown (e.g. 250 100 170 260 500) are likely dimensions in millimeters (mm) representing the thickness or depth of the components though the specific labels for the individual layers are not provided for all dimensions.
🌱 LOAD AND PLANTING DEPTH COMPARISON
This stepped diagram demonstrates how the type of vegetation and the depth of the soil/planter correlate with the structural load (weight) imposed on the roof. All depths are measured from the Roof Level (Roof Lvl.).
1. Direct Correlation: There is a direct positive correlation between the depth of the planting medium and the load it imposes on the roof structure. Deeper soil is heavier and supports larger heavier plants.
2. Structural Requirement: Engineers must account for the required dead load (weight of the materials *including the fully saturated soil*) and the live load (weight of people snow etc.) when designing the roof slab. A roof designed for a simple ballast layer (like the 240 Kg/m² grass load) cannot support the 865 Kg/m² load required for large trees.
3. Vegetation Type: The depth dictates the type of vegetation that can be sustained ranging from shallow-rooted grass to deep-rooted 3m tall trees.
