Why is this important?

Innovation in construction materials is when the composition of such materials are modified by incorporating raw-materials, ones that are not normally used in the material manufacturing and construction process, with the end goal of minimizing the ecotoxicity of the material. In layman’s words, the ecotoxicity of a material is the measure of how toxic the material’s interaction with the general surrounding environment is. They theorize that the best way to evaluate this characteristic is through life cycle assessments (LCA) of the materials at hand, which is an evaluation of the environmental impact of a material through its entire life cycle.

Research shows that certain raw materials used in construction that initially did not have a positive ecological impact can be modified with the addition of certain chemicals to lead to construction materials that have lower hazardousness to the environment. Therefore, we can develop and manufacture products and use design choices that will mitigate their environmental impact and increase their construction sustainability.

Moreover, the incorporation of chemicals used in the raw materials, and the method through which they are combined, would increase the cost of the finalized construction materials to an extent where they would not be practical to incorporate at this time. Over time, through research, development, and refinement of the process would be beneficial and perhaps, even more, cost-effective, but currently, an increase in the price point of construction materials to a range between 40%-60% would not entice consumers to implement DADUs composed of such material- the estimation of such an increase in price stems from research, novel manufacturing processes, and the learning curve of manufacturers. 

Methods:

There are multiple methods of incorporating design factors that have been thoroughly implemented in DADUs and other ecologically friendly housing units that can greatly benefit the ecological impact of the DADUs we plan to implement while providing minimal- if any- additional construction costs. On top of that, these design factors have great potential to minimize living and maintenance costs for the homeowner. 

The Seattle Planning Commission (SPC) recommends multiple methods for minimizing the ecotoxicological impact of housing units on the environment.

1. The installation of photovoltaic solar electric and solar heated-water systems would aid in reducing the use of non-renewable energy sources such as gas, coal, etc. This could also be incorporated within the design of the house through methods such as strategic window placement and the utilization of floors and walls that are thermally insulated.
2. Utilizing features for water conservation, such as high-efficiency washing machines, dishwashers, and rainwater harvest systems can mitigate the impact that humanity has on local streams and rivers- minimizing our growing impact on freshwater organisms.
   1. It would be economically beneficial as well, reducing water bill costs if implemented correctly. In a city such as Nashville with 10 more inches of rain per year than the rest of the USA, utilizing such mechanisms would be even more efficient here- both fiscally and environmentally. 
3.  Efficient material use also has the propensity to aid our agenda by incorporating advancing framing techniques, like advanced house framing techniques (AFT), which would utilize less natural materials, as well as minimize costs for those looking to manufacture DADUs. They also increase the insulated wall area by reducing the thermal flow that occurs when subpar insulations displace the insulation between the frames. The presence of more insular material instead of more wood would decrease the need for heaters that consume energy.
   1. To implement this technique, space the wooden framing at 24 inches on center instead of 16 inches, decreasing the frequency of the framing.
   2. According to the US Department of Energy, fully implementing AFTs can lead to materials cost savings of up to around 170$ for a 400 sq/ft housing unit, can cause labor cost savings of between 3% and 5%, as well as decreasing annual and cooling costs for up to 5%.

Finally, the DADUs can incorporate design approaches- with regards to efficient sizing- recommended by the SPC, such as minimizing hallways and other transitional spaces in the units, creating open-plan designs that do not adhere to common, large homes, and by essentially increasing the use of the smaller space by combining the functionality of space, such as lofted bedrooms or kitchens. As seen in this section above there are numerous methods of creating environmentally and fiscally sustainable homes that can help various ecosystems.