Retention roof
In addition to sedum and green roofs, there are also retention roofs that can store large amounts of water. A water storage package is installed on a retention roof. This is done by placing crates with a large water storage capacity on the roof structure. The water in these crates is retained or drained slowly. A green roof is installed on top of the crate structure, which makes use of the water underneath.
Existing roofs are usually not designed to support the weight of a retention roof. Such a roof is more difficult to install yourself. If you are interested in a retention roof, hire a specialized company.
Costs
A retention roof is more expensive than a sedum or green roof. This is due to the additional buffer capacity that needs to be built in.
Use of space
A retention roof does not take up any extra space in your garden.
Difficulty
It is important that the roof can bear enough weight to prevent leaks. The roof structure must have sufficient load-bearing capacity. There is always water on the roof, so everything must be properly finished and checked.
Earthmoving
No earthworks are required. However, the substrate and plants must be installed on the roof.
Maintenance
Just like in the garden, plants on the roof also need maintenance. Fertilizing annually is good for the plants. Tip: think about maintenance before planting. Checking drainage is important.
Climate goals
Retention roofs reduce heat stress and can store water for reuse. The roof also contributes to biodiversity through its vegetation.
Biodiversity
Contribution to improving biodiversity
Points of attention
- The roof must be able to bear a minimum load of 100 kg/m².
- Check the drains regularly.
- It is necessary to have an overflow option for when the storage room is full.
- Annual fertilization benefits the plants.
- Grasses and weeds should be kept away from the planting as much as possible.
