497 tonnes less carbon, 30% faster builds — how IJM Timber Engineering transformed housing

Carbon savings that are data-backed and project-aligned

As part of their delivery, IJM used a typical house type (B1, 150m² gross area) as the basis for a detailed life-cycle assessment (LCA), extrapolating the results across the 30-home development. The analysis, conducted in-house using One Click LCA, revealed the following:

Per house (B1):

• Net GWP (A1–A5): -20,087 kgCO₂e
• Biogenic carbon stored: -29,886 kgCO₂e
• Fossil emissions: 9,799 kgCO₂e

30 homes (modelled extrapolation):

• Net GWP (A1–A5): -497,620 kgCO₂e
• Biogenic carbon stored: -737,551 kgCO₂e
• Fossil emissions: 239,931 kgCO₂e

These results demonstrate how biogenic carbon stored in responsibly sourced timber can drive project-level net carbon savings, helping designers and developers make decisions that align with ESG and regulatory goals.

“Timber and MMC were essential to hitting our Passive House targets and tight timelines,” said Charlie Conlan, Sustainability and Design Lead at Ballymore. “IJM gave us the data confidence we needed to push sustainability further without increasing risk.”

The LCA for the Drumnigh Oaks model covered stages A1 to A5, representing the full cradle-to-site impact: raw material supply (A1), transport (A2), manufacturing (A3), transport to site (A4), and construction/installation processes (A5). By using EPD-backed data, IJM could model not just material emissions, but the logistical and site emissions too — critical for understanding the real embodied carbon impact of prefabricated timber systems versus traditional masonry construction. The result is a reliable and repeatable model for measuring and reducing embodied carbon across projects.

Verified EPDs — delivered in-house using One Click LCA

The accuracy of the Drumnigh Oaks model rests on product-specific EPDs, published by IJM for three of their core wall types. These are calculated and verified according to EN 15804, and include both embodied and biogenic carbon figures:

• 0.18 W/m²K Ecowall — GWP (A1–A3): -11.40 kgCO₂e/m²
• 0.15 W/m²K Ecowall — GWP: -8.22 kgCO₂e/m²
• 0.13 W/m²K Ecowall — GWP: -4.96 kgCO₂e/m²

“We use One Click LCA not just to meet requirements, but to deliver value,” explains Sean McCaughey, Technical Manager at IJM. “We give clients project-specific LCAs and EPD-supported designs before we even start building. That makes carbon-conscious decision-making possible at the earliest stages.”

Low carbon by design — MMC in practice

IJM’s MMC process is designed around high repeatability, minimal waste, and rapid delivery. Wall panels, floors, and roofs are fabricated off-site using CAD/CAM technology, allowing for tighter tolerances and dramatically reduced errors. Their facilities are powered by renewables, and operations use electric vehicles to further lower operational emissions.

With a modular “kit-of-parts” approach and precise scheduling, IJM achieved:

• Single-day structural assembly for semi-detached units
• 30% time savings over masonry construction
• Minimised on-site labour and disruption
• Greater control over carbon performance across supply chain

Embedding lifecycle thinking across the supply chain

EPDs and LCAs are not one-off exercises at IJM — they are part of a broader lifecycle thinking strategy. As part of their customer service model, IJM engages early with clients to provide accurate carbon modelling, enabling alignment with green finance frameworks, Part L requirements, and future EPBD obligations.

“We’re committed to building in balance,” says Peter McCaughey, Director. “This means balancing performance, cost, and carbon — without compromise. The data we generate with One Click LCA helps us get that equation right every time.”

A replicable model for scalable decarbonisation

According to Peter McCaughey, timber frame housing now accounts for approximately 60% of new home construction in Ireland — a dramatic rise from just 1% in 1990. With policy tightening and carbon tracking becoming standard practice, IJM’s verified, low-carbon, prefabricated systems offer a clear, scalable path forward.

“From passive design to fast-track delivery, our systems show what’s possible when sustainability and certainty go hand in hand,” adds Sean McCaughey.

With new policies like the EU Energy Performance of Buildings Directive (EPBD) and national carbon reporting schemes coming into force, manufacturers will increasingly need to demonstrate compliance through verifiable product data. Tools like One Click LCA Generator empower companies like IJM to stay ahead of these requirements — turning sustainability into a competitive edge while supporting clients pursuing green finance, ESG benchmarks, and certification schemes such as LEED, BREEAM, and HPI.

Building low carbon homes starts with good data

The Drumnigh Oaks development doesn’t just highlight the benefits of data-backed MMC or timber frame construction — it shows how manufacturers like IJM are equipping developers with the insights to lead. With third-party verified EPDs, robust LCAs, and an embedded carbon mindset, they’re delivering performance you can measure — and trust.

“At the Irish Green Building Council, we see lifecycle carbon assessment as an essential tool to decarbonise Ireland’s built environment. Manufacturers who adopt verified EPDs and support early-stage LCA — like IJM Timber Engineering—aren’t just future-proofing their products, they’re actively enabling better buildings and helping the market meet carbon performance targets today.” — Pat Barry, CEO, Irish Green Building Council