Foundations Emissions Assessment

Comparison of Foundation System Carbon Impacts

MyImprint conducted a life cycle assessment comparing four commonly used foundation construction techniques in New Zealand. This summary is based on the Foundation System Carbon Comparison 2024 report, prepared for StopDigging. The assessment focuses solely on embodied carbon and excludes operational energy.

For the concrete pad and Rib Raft comparison, 25 MPa low-carbon concrete was used, with an average emission factor of 147.6 kg CO₂/m³, based on data from major suppliers—Firth, Allied, and Stevenson.

In the timber pile construction, 17.5 MPa in-situ concrete (unreinforced) was used, with an estimated emission factor of 216 kg CO₂/m³

Key Findings:

• Figure 1 shows that timber piles have the lowest carbon impact when materials are used once and then disposed of.

• Figure 2 compares the total emissions of a use case requiring a relocation of the building, and so a reuse of materials. It demonstrates that Stopdigging Groundscrews, when reused across both sites and subsequently recycled, have the lowest overall carbon impact.

Figure 1: Single Use, then the Recycling/Disposal

Figure 2: Total Emissions when a second relocation is required, When Ground Screws are Reused