1.   Engineering aspects

Firstly, floors are a significant component of buildings, and their environmental impact extends beyond just the materials used in their construction. The entire life cycle of a floor, from raw material extraction to manufacturing, transportation, installation, maintenance, and eventual disposal or recycling, all contribute to its environmental footprint.

Secondly, buildings themselves have a considerable impact on the environment, with the construction sector being one of the largest contributors to global carbon emissions. Choosing the right floor material can significantly affect a building’s overall sustainability and carbon footprint.

Thirdly, different floor materials have varying environmental impacts. For example, some materials may require extensive energy and water use during production, while others may emit harmful chemicals or have a high carbon footprint. By conducting an LCA, stakeholders can compare the environmental impacts of different floor options and make informed decisions based on factors such as energy use, greenhouse gas emissions, water consumption, and waste generation.

Moreover, considering the long lifespan of floors, typically spanning decades, the environmental implications of their selection become even more significant over time. A thorough LCA helps in understanding not only the immediate environmental impacts but also the long-term sustainability of the chosen floor option.

2. Life Cycle time-line

 

table of interventions	life-span	routine maintenance	significant intervention	duration for routine maintenance	duration for significant maintenance
concrete floor slab	75	7.5	25	7 days	1 month
wood-concrete  composite floor slab	45	3.5	15	7 days	1 month
cross-laminated timber floor slab	63	3.5	17.5	7 days	1 month

3. Life Cycle Inventory and Analysis

As we analyze how many interventions are required over the lifecycle of each option, combined with the data from Table 2, we can multiply and add up the overall lifecycle energy consumption and emissions for each option. Here are the results.

Analysis results of energy consumption with the unit megajoules for Concrete Floor Slab(blue), Wood-Concrete Composite Floor Slab(orange), and Cross-Laminated Timber Floor Slab, respectively. 

 

Results of CO2 emissions with the unit e/m² for Concrete Floor Slab(blue), Wood-Concrete Composite Floor Slab(orange), and Cross-Laminated Timber Floor Slab, respectively

 

The NOx emissions results with the unit kgNOx/m² for Concrete Floor Slab(blue), Wood-Concrete Composite Floor Slab(orange), and Cross-Laminated Timber Floor Slab, respectively.

 

The SO2 emissions with the unit kgSO2/m² for Concrete Floor Slab(blue), Wood- Concrete Composite Floor Slab(orange), and Cross-Laminated Timber Floor Slab, respectively.

4. MCDM – Analytic hierarchy process (AHP)

 Concrete Floor Slab
Advantages:
⦁ Durable and long lifespan, potentially reducing the need for replacement.
⦁ Fire-resistant properties.
Disadvantages:
⦁ Higher energy consumption and CO2 emissions during production.
⦁ Heavy weight may require additional structural support.
 Wood-Concrete Composite Floor Slab
Advantages:
⦁ Combines the strength of concrete with the sustainability of wood.
⦁ Potentially lower environmental impact compared to traditional concrete.
Disadvantages:
⦁ Moderate maintenance requirements for wood components.
⦁ Limited fire resistance compared to concrete.
Cross-Laminated Timber (CLT) Floor Slab
Advantages:
⦁ Renewable and sustainable wood resources.
⦁ Lower environmental impact across various categories.

Disadvantages:
⦁ Requires protection against moisture and insects.
⦁ Limited fire resistance compared to concrete.
Cross-Laminated Timber (CLT) Floor Slab
Advantages:
⦁ Renewable and sustainable wood resource.
⦁ Lower environmental impact across various categories.
Disadvantages:
⦁ Requires protection against moisture and insects.
⦁ Limited fire resistance compared to concrete.
Recommendations
For Lower Environmental Impact:
⦁ Consideration: Adopt the Cross-Laminated Timber (CLT) Floor Slab option due to its lower estimated environmental impacts across all categories.
For Moderate Environmental Impact:
⦁ Consideration: The Wood-Concrete Composite Floor Slab option presents a moderate environmental impact and may be a suitable compromise between environmental considerations and specific project requirements.
⦁ Considerations for Concrete Floor Slab:
Advantages: Durable and fire-resistant.
Disadvantages: Higher environmental impact, weight considerations.
Consideration: Use concrete cautiously, considering specific project needs.
⦁ Additional Considerations:
Operational Efficiency: Assess operational energy efficiency and long-term costs associated with each flooring option.
Life Span and Maintenance: Consider the expected life span and maintenance requirements for each option.

Conclusion
This comprehensive report provides a detailed evaluation of environmental impacts, advantages, and disadvantages associated with different flooring design options. While environmental considerations are crucial, it is essential to balance them with project-specific needs, operational efficiency, and long-term costs.