Construction of Container House Roof

When constructing a green roof on a container house, it is necessary to comprehensively consider factors such as structure, waterproofing, drainage, and plant selection. The specific steps are as follows:

1. Structural Support Design
The load of the green roof needs to be transferred to the four corner columns of the container through steel or wooden frames to ensure the safety of the foundation. If the roof area is large or the plant layer is thick, an engineer should calculate the load distribution to avoid local overloading that could cause structural deformation. The steel beams or wooden frames should be reliably connected to the original container frame to form an integrated load-bearing system, while also reserving space for the installation of the plant growth layer and drainage system.

2. Layered Construction of the Roof

• Waterproof Layer: Select a strong root-resistant waterproof membrane such as EPDM, cover the entire roof surface and extend it to the edges to ensure there are no gaps. The waterproof membrane should be sealed at nodes such as drainage outlets and pipes to prevent moisture from penetrating into the interior of the container.
• Root Barrier: Lay anti-root materials such as high-density polyethylene (HDPE) on the waterproof membrane to prevent plant roots from penetrating the waterproof layer and extend the lifespan of the roof.
• Drainage Layer: Use gravel (particle size 5-20mm) or a dedicated drainage mat (such as a plastic corrugated board) with a thickness of about 50-100mm to ensure that excess water is quickly drained, avoiding waterlogging that could cause plant root rot or increase the roof load.
• Filter Fabric: Lay non-woven fabric on the drainage layer to prevent lightweight soil particles from clogging the drainage channels while allowing moisture to penetrate.
• Growing Medium: Use lightweight artificial soil (such as a mixture of perlite, vermiculite, and humus) with a bulk density controlled between 0.3-0.8g/cm³ to avoid structural failure due to the excessive weight of ordinary garden soil.
• Plant Selection: Prioritize drought-tolerant, cold-tolerant, and shallow-rooted plants such as Crassulaceae succulents, Sedum lineare, local grass species, or wildflower combinations to reduce later maintenance costs.

3. Drainage System Optimization
Set up drainage outlets or pipes at the low points of the roof and connect them to an external rainwater collection system or ground drainage ditch. Lay a gravel buffer layer around the drainage pipes to prevent soil and roots from clogging the pipes. If rainwater reuse is required, a water tank and filtration device can be installed to achieve water resource recycling.

4. DIY Construction Process

• Reinforce the Roof: Install steel or wooden frames to ensure structural stability.
• Base Layer Treatment: Clean the roof surface, lay the waterproof membrane and root barrier, and secure the edges with battens.
• Boundary Definition: Use wood or metal strips to make a fence around the roof edges, with the height determined according to the thickness of the plant layer (usually 100-200mm).
• System Installation: Lay the drainage layer and filter fabric in sequence, install the drainage pipes, and connect them to the collection system.
• Soil Filling and Planting: Pour in the lightweight soil, level it, plant the plants, and cover with a thin layer of mulch (such as pine bark) to reduce water evaporation.
• Maintenance and Adjustment: Check that the drainage outlets are unobstructed, adjust the plant spacing, and ensure a suitable initial growth environment.

Precautions: The green roof needs to be regularly cleaned of fallen leaves, the drainage system checked, and plants replanted or pruned according to their growth conditions. Lightweight structures should be reinforced before extreme weather to avoid damage from strong winds or heavy rain.