Assignment First


大面积的绿色与密集的绿色屋顶形成对比,显得更加轻盈。它是浅得多,并有一个增长的衬底不超过200毫米的深度(Axter, 2008)。这可能是最容易建造的,因为浅层的衬底布局可能不会花费太多,而且屋顶区域的净空对于这种类型的绿色屋顶来说可能非常低。这种形式的绿色屋顶对水的需求没有密集的绿色屋顶系统那么多。因此,在基督教青年会建筑中建造这种形式的绿色屋顶意味着不需要额外的水安排和规划。最低限度的维护也是一个优势;因此,基督教青年会管理层将不再需要安排受过专门培训的员工。

这种形式的生态屋顶的缺点是屋顶不能支持多种植物。在这里生长最多的是肉质小而生长缓慢的植物。绿色屋顶没有生物多样性,不能用来增加植被,甚至不能为鸟类提供居住的场所,等等。这里最有益的结果是水的保留能力,最终导致建筑内部冷却(Axter, 2008)。



The extensive green in contrast to the intensive green roof is lighter. It is much shallower and has a growing substrate that is not more than 200 mm in depth (Axter, 2008). This is perhaps the easiest to build given that the shallow substrate layout might not cost much and also the roof area clearance could be really low for this type of Green roof. The water requirements for this form of green roof are not as much compared to the intensive green roof system. So the construction of this form of a Green Roof in the YMCA building would mean that no extra water arrangement and planning have to be done. The minimal maintenance is also an advantage; hence, the YMCA management will no longer need to arrange for specially trained employees.
The cons to this form of an eco-roof are that the roofing will not support much variety of plants. Small low growth plants of the succulent variety are the most that would grow here. The green roof is not biodiverse and cannot be used to increase vegetation or even provide a form of place to live for birds, etc. The most beneficial outcome here is the water retention capacity that eventually leads to the internal cooling of the building (Axter, 2008).
On the other hand, the intensive green roof will present many advantages for a building owner who wants the building roof to be a biodiverse habitat (Appendix 1). Intensive green roofs are generally heavier, with a deeper layer of growing substrate, and support a wider variety of plant types. The heavy weight makes them have the requirement of more water, irrigation facilities and constant maintenance, which could be a problem in the long run. The high engineering landscape required might not be affordable in the case of the YMCA building. Moreover, the YMCA is not a roof garden for decking purposes either, and its main functional need is for the cooling of the building.