Want to plant a large lawn on the roof, how to be waterproof? I'm afraid that rain will penetrate into the house. If there is too much rain, the grass will die.

You can refer to the design of typical green roofs. If there is too much rain, it will be submerged. The lower layer needs to be laid with drainage pipes and root-blocking layers. Otherwise, the lower layer will be penetrated by plant roots.

From bottom to top, there are root blocking layer, drainage layer, filter cushion layer, cultivation substrate layer and vegetation layer in turn.

Perforated pipes should be buried in the drainage layer and connected with rainwater pipes if necessary. The material of the root-blocking layer has a special manufacturer, and the filter layer can specially consider some large-aperture fillers.

Grass can be considered low potential, as long as the drainage pipe meets the demand. Specific design information can be asked about the relevant design units and construction units.