How does offsite timber construction compare to typical masonry building techniques through life cycle assessment? 

Luke Clucas

Test Methods
Technical Investigation/ Case Study
Life Cycle Assessment

For copy of full dissertation, contact:
lukeclucas@hotmail.com

Supervisors:
Olivia Golden
Jim Roche

11% of our national emissions are caused by the production and transportation of construction materials and constructing buildings and infrastructure.

This study was carried out with the ambition of exploring two domestic construction types in use in Ireland to see which construction is more sustainable with focus on the life cycle analysis and embodied carbon of each construction. This research will examine what materials contribute most to the constructions global warming potential as well as other impact stages.  

With the use of a case study of a modern domestic dwelling in Ireland the relevant information was obtained to develop a Revit model of the case study building. The case study building’s wall is masonry construction, therefore the build ups of the walls, roof and floor designed and specified by the architect are used in the life cycle assessments for the masonry construction. As for the off-site timber panel construction build-up, they are designed and specified by an Irish company that develop modular domestic homes. The Revit model of the case study building was used to input the two construction types. Revit plug-ins ‘Tally’ and ‘One Click LCA’ are then used to calculate the life cycle of the two constructions by using the material information gathered in the Revit model. This study also examines the two life cycle assessment calculation softwares usability and applicability to Irish context.
 
This study confirmed my original observation that onsite masonry construction has a higher environmental impact compared to that of offsite timber construction. This study focuses on the global warming potential of the two constructions and the materials that contribute most to this. Four calculations were carried out on both softwares, firstly only the external walls of both constructions were compared. The global warming potential of the offsite timber panel was lower than that of the masonry wall by 74.8% according to Tally and 86.5% according to One Click LCA. The most contributing materials were EPS insulation in the offsite panels and concrete blocks in the masonry wall. When looking at the whole external building fabric (Walls, Roof & Floor) the offsite timber panel building had a lower global warming potential by 27.4% according to Tally and 27.8% according to One Click. This calculation is much closer to that of just the wall comparison due to the high amount of EPS insulation used in the floor of the offsite timber panel building.