Roof Greening FAQ
1) Green Roof Function:
1. Improve the urban environment, the quality of the people living and working environment;
2. Mitigate atmospheric dust, clean the air
3. Protect the top of the building, extend roof materials service life.
4. Reduce the indoor temperature
5. Weaken the urban noise
6. Increase air humidity, clean water
7. Improve the utilization of land resources
2) Green Roof Advantage
1. Energy Saving
Thermal insulation 5-70C, up to 30% saving electricity; adsorb lots of dust in the air, reduce atmospheric haze; release fresh oxygen, absorb carbon dioxide, reduce carbon dioxide emissions; save natural rainfall, reduce water leakage on the roof alluvial ground, reduce pressure on urban drainage.
2. Green and Beautification
Do not take any land area to greatly increase the green area, improve the green coverage, reduce the cost of roof greening, landscape unit of the landscaping, improve air quality, improve the ecological environment.
3. Protection of the roof
Insulation roof exposed affected by the sun, rain, wind, frost, snow and other natural factors directly, the excellent ecological thermal insulation properties, effective in reducing the thermal expansion and contraction of the roof structural damage, especially extend the life of the waterproof layer.
3) Matters Needing Attention for Roof Greening System
1. Leakage-proof processing
Putting soil and growing vegetation on the roof can protect the roof from summer sun exposure and baking, thus obviously reduce the temperature of roof, however, acid and alkaline from watering and fertilization will erode the waterproofing later, which will lower its waterproof properties. The solution is before construction daub one 1.5cm-2.0cm layer of ash Portland cement mortar in the original roof waterproofing layer, which can improve the water resistance, corrosion resistance and penetration-proof quality, and finally enhance the waterproofing capability with the joint action of green system. Protecting the roof from leaking is the key technology of the waterproof layer, but waterproofing and drainage is a problem in two aspects, therefore we should take care of roof drainage system. In the construction and design of roof greening, planting pool, water pool and road should be designed according to the roof drainage system to avoid blocking up or isolating the original outfall, do not change slope at will. Especially, drainage pipeline of drainage layer in large growing pool should coordinate with the outfall of the roof, please pay attention to the relevant elevation difference to make sure the extra water is easy for drain from the growing pool.
2. Bearing Problem
Bearing capability should be taken into consideration, which is related to safe issues. The bearing capacity of the buildings is subject to bearing ability of beam slab column and foundation under roof garden. Due to the bearing capacity of housing structure affects the cost directly, so the allowing load of the roof is subject to the cost. In order to solve the problem, should take matrix cultivation. For example, use specialized roof greening soilless lawn, adjust matrix dosage according to need when product soilless lawn to substitute the loam layer with the same thickness, which is needed by the roof greening, thereby reducing roof bearing significantly.
3. Bad environment will cause plants survival problem.
Bad environment will cause plants survival difficult problem should be into green roof consideration. Medicinal plants growing on the roof is not easy, due to environmental factors roof obviously different with the ground, light, temperature, humidity, wind, etc. With the increase of story showed different changes. For example: Roof solar radiation, warming fast, violent storms of cold heat, the temperature difference between day and night, and so on. Therefore, various types of plant growth characteristics need to select the suitable environment for the growth of plants. The plants should be resist cold, heat, drought, lean, vigorous flowers and trees. Bags containing flowers and trees are the best choice for seedlings to ensure survival.
4. Design Problem.
Design problem should be into green roof consideration. First, design should consider the special requirements of green roof, such as: load-bearing roof, roof leak, lighting, water supply and drainage, leakage, etc. Second, the roof garden designshould consider local conditions. Roof garden area is small, within the limited roof area should combine sculptures, road, lighting, pools, fountains, flowers, trees, pavilions sketches, architectural style together.
