Why can't we grow vegetables on the roof?

Many owners who live on the top floor have a flat terrace on the floor, and they think it is a waste of space to use it, so they plant flowers and vegetables on it. I have been exposed to floor design for several years before, and I know a little about floor bearing and floor waterproofing. If you read the following carefully, you will certainly understand why vegetables can't be grown on the roof.

Temporarily do not consider the requirements of property management and the impact and feelings on other owners. There are two main reasons why vegetables can't be grown on the roof.

The first is the problem of electric leakage. In China, permanent buildings are divided into four waterproof standards, and general industrial and civil buildings are divided into three waterproof standards, and the effective protection period is 10 year. In other words, for commercial housing, it is very conscience for developers to ensure that the roof will not leak for 10 years. But in real life, there are not many conscientious developers. Besides, you grow vegetables on it. Acidic substances or alkaline substances in the soil layer where vegetables are planted, as well as chemical fertilizers and pesticides used, have a strong corrosive effect on ground buildings and waterproof materials, which you can't see with the naked eye, and there will be no obvious performance after one or two years. But three years and five years, in the long run, it will definitely lead to many invisible leakage sources on the floor. Of course, this kind of leakage source will not form a direct "drip" leakage in rainy days, but the rain will slowly penetrate the floor, leading to mildew, degumming and peeling of the indoor top surface. No matter how heavy the rain falls on the floor without vegetables, the floor will always dry, and the dry state is normal. Once the grain is planted, the soil layer will remain wet for a long time after watering, rain and snow in summer, so the ground and waterproof materials are always wet, not to mention acid and alkali corrosion. It's just that this wet state will accelerate the failure of floor waterproofing materials. The cost of re-making waterproof layer is very high, ranging from thousands to tens of thousands, which is not as good as the original waterproof effect. In contrast, what is the income from growing vegetables?

Growing vegetables on the roof leads to the failure of waterproof layer and peeling of indoor top surface.

The second is the bearing problem. There is a standard load in architectural design. The standard design of a general civil residence is 2000N/m2, which is about 200 kg, including loads such as floor personnel, furniture, flowerpots, ornaments and decoration. Generally speaking, short-term overload will not have any impact, but long-term overload will inevitably affect the building structure. When planting vegetables on the floor, the soil layer and fence above will inevitably increase the bearing capacity of the floor, especially in rainy and snowy weather, the weight of the soil layer will increase exponentially because of a lot of water, which will inevitably affect the quality and service life of the building in the long run.

Therefore, it is not worth the loss to grow vegetables on the floor. We know how to cherish the clothes of 1000 yuan, and we also know how distressed it is to accidentally rub it with a car of 100000 yuan. Why would someone ruin millions of buildings like this?

Of course, in recent years, there have been new designs in the building structure. For example, in some places of Wenchuan reconstruction, the problem of growing vegetables on the top floor was considered in architectural design. This stepped vegetable garden is a special design. It is incomparable to ordinary commercial housing.

Stepped vegetable garden is a new design.