Most residential landscapes include a combination of hardscapes (patios,decks,walkways,and driveways) and ornamental plants. As you think about the design,construction,and maintenance of your landscape,consider how sustainable each component is and how it could be modified to be more sustainable.
As it relates to hardscape materials,sustainability includes three key factors:
* How well does the material incorporate the principles of”reduce,reuse,recycle”?
* What is the product’s impact on the environment once installed?
* What are the material’s maintenance requirements?
Use fewer virgin materials in your landscape. Reuse existing materials when possible or select recycled products. A number of new recycled landscape prod- ucts are available in a variety of textures and colors. Many combine recycled plastics with wood by-products. These materials require almost no maintenance and last longer than wood. They can be used for decks,fences,benches,and planters.
Hardscape materials vary in their effect on the environment.For example, pavement prevents water from soaking into the soil,thus increasing runoff, which can carry contaminants into streams.Porous materials,on the other hand, allow water to soak into the soil.
It often is easier to evaluate the initial cost of construction materials than their long-term costs. However,the long-term maintenance costs of some building materials can be significant. Before choosing a product,research its initial and long- term costs as well as its recommended uses.Using a product improperly not only might be dangerous, but likely will increase your overall construction and maintenance costs.
The hardscape options listed below vary in their sustainability and short-and long-term costs.For specific information,consult a landscape construc- tion reference or a landscape contractor.Detailed information is available in Sustainable Landscape Construction:A Guide to Green Building Outdoors by J.William Thompson and Kim Sorvig.
Always check local building regulations to make sure the product you select is approved for use in your area.
Wood plastic composites are true composite materials and have properties of both materials. They have stiffness and strength between those for plastic or wood, but the density is generally higher than either. The properties of Wood plastic composites come directly from their structure: they are intimate mixes of wood particles and plastic. The plastic effectively coats the wood particle as a thin layer. The structure is shown at left.
The high moisture resistance of WPCs (water absorption of 0.7% compared to 17.2% for pine) is a direct result of the structure. Moisture can only be absorbed into the exposed sections of wood and is not transmitted across the plastic boundaries.
The result is that WPCs are extremely moisture resistant, have little thickness swell in water and do not suffer from fungal or insect attack.
The properties of WPCs can be tailored to meet the product requirements by varying the type of wood or the type of plastic – the PE based products are cheaper and have a higher heat distortion temperature than the PVC based products but the PVC products are easier to paint and post treat.