Post-Occupancy Evaluation

Section 1

Purpose

Post-Occupancy Evaluation (POE) is the structured assessment of a building's performance in use against the design intent and the client's stated requirements, conducted during and after the Defects Liability Period at RIBA Stage 7. The QS's contribution to POE focuses on cost performance: comparing actual operational and maintenance costs in year 1 against the NRM3 lifecycle cost plan; assessing actual energy costs against the design energy model; and identifying whether any significant post-completion costs were attributable to design failures, specification decisions, or contractor defects.

RIBA Plan of Work 2020 establishes POE as a formal Stage 7 obligation for the design team. RICS Lessons Learned (1st ed., April 2016) identifies post-occupancy as one of the most valuable stages for capturing project lessons — actual building performance is the definitive test of whether design, specification, and cost planning decisions were correct. The QS who contributes to POE builds a feedback loop between initial estimating and actual cost outcomes.

POE findings also have direct professional development value: comparing NRM3 lifecycle estimates against actual year-1 costs reveals whether the elemental maintenance cost rates used in the estimate were accurate, whether particular building systems or components are under-maintained or over-specified, and what adjustments are needed for future lifecycle cost plans.

Section 2

Key Principles

RIBA Plan of Work 2020, Stage 7: POE is a formal requirement; the design team should plan for and conduct a POE within 12 months of occupation; findings should be reported to the client and used to inform the design team's future work.
RICS Lessons Learned (1st ed., April 2016): POE provides the most accurate lessons learned for QS firms — actual energy costs, maintenance expenditure, and defect costs calibrate NRM3 lifecycle cost models and estimating rates.
NRM3 (2022 ed.): Section 4 covers lifecycle cost planning; the POE should assess actual year-1 costs against the NRM3 cost plan for maintenance, renewal, and operation; significant variances should be explained and used to update the cost model.
RICS Cost Analysis and Benchmarking (2nd ed., August 2024): post-occupancy cost data should be collected in the same SFCA elemental format as the initial cost analysis for meaningful comparison over time.
Soft Landings Framework (BSRIA): identifies the 3-year post-occupancy monitoring period as best practice; the QS can contribute the cost performance data stream within this framework.

Section 3

Practical Application

Step 1

At the start of the DLP, set up the POE data collection framework: agree with the client what data will be collected (energy bills, maintenance invoices, reactive repair costs, tenant satisfaction surveys); confirm who collects each data type and when.

Step 2

At 6 months and 12 months post-PC, collect the first year cost data: energy bills; planned preventative maintenance (PPM) invoices; reactive repair costs; cleaning costs; any reactive defect remediation costs not covered by the DLP.

Step 3

Compare year-1 actual costs against the NRM3 lifecycle cost plan at elemental level; calculate variances and investigate reasons — specification differences, occupancy pattern differences, early maintenance failures.

Step 4

Contribute the QS cost performance assessment to the POE report prepared by the design team — the cost section should include: NRM3 year-1 forecast vs actual; energy cost forecast vs actual; defect remediation costs (separated from normal maintenance); overall cost performance commentary.

Step 5

Identify any significant cost variances that suggest a design or specification decision should be revisited for future projects — for example, a building system with actual maintenance costs significantly above the NRM3 estimate.

Step 6

Update the firm's NRM3 cost models with actual year-1 cost data; flag any elemental rates that consistently differ from actual costs; distribute the updates to the estimating team.

Step 7

Record POE findings in the firm's lessons learned knowledge base alongside the Stage 6 cost analysis; POE data is most valuable when it can be linked back to the original design and procurement decisions.

Section 4

Common Mistakes to Avoid

Treating POE as optional or a design team responsibility only — the QS's cost performance contribution is a distinct and valued element of POE; omitting it leaves the POE incomplete.
Collecting POE data without linking it back to the NRM3 cost plan — raw maintenance invoices without comparison to the lifecycle cost estimate have no analytical value.
Using actual year-1 costs without adjusting for occupancy patterns — a building occupied below design capacity will have lower energy costs; the comparison with design intent must be normalised for actual occupancy.
Failing to update NRM3 cost models with actual data — POE findings that are not fed back into future estimates have no lasting value; the learning loop is only complete when the models are updated.
Not recording who carried out the POE and when — in the event of a later dispute about building performance (e.g. latent defect claim), the POE records may be important evidence.

Section 5

APC Competency & Quick Reference

Asset Management Level 2 — lifecycle cost management, NRM3, post-occupancy cost analysis
Project Financial Control and Reporting Level 3 — POE cost performance reporting, client communication

What is the QS's specific contribution to a Post-Occupancy Evaluation?

The QS contributes the cost performance assessment: comparing actual year-1 operational and maintenance costs against the NRM3 lifecycle cost plan; comparing actual energy costs against the design energy model; quantifying defect remediation costs and attributing them to cause (contractor workmanship, design failure, specification decision); and identifying lessons for future lifecycle cost plans. The QS does not assess user satisfaction or technical building performance — those are design team responsibilities.

How should the QS compare actual POE costs against the NRM3 lifecycle cost plan?

At elemental level using the NRM3 element structure. For each element (e.g. roof finishes, M&E services, external envelope), compare the NRM3 year-1 maintenance cost estimate to actual invoiced costs. Calculate variance (£ and %). Investigate outliers — is the variance due to a specification difference, an occupancy pattern difference, an early maintenance failure, or an inaccurate NRM3 rate? Document the explanation.

What is the Soft Landings Framework and how does it relate to POE?

Soft Landings (BSRIA 2009, updated 2018) is a framework for ensuring buildings operate as designed by extending the design team's involvement into occupancy. The QS contributes the cost performance data stream over the 3-year Soft Landings period. This covers initial post-occupancy review (year 1), fine-tuning period (years 1–3), and longer-term performance monitoring. The lifecycle cost comparison is most meaningful after the fine-tuning period when building systems are fully optimised.

Section 6

Defects Liability & Post-Occupancy Checklist

☐

Task

☐

POE data collection framework agreed with client at start of DLP

☐

Year-1 cost data collected: energy, PPM, reactive repairs, defect remediation

☐

Actual year-1 costs compared to NRM3 lifecycle cost plan at elemental level

☐

Significant variances investigated and explained

☐

QS cost performance section contributed to POE report

☐

Firm's NRM3 cost models updated with actual year-1 data

☐

POE findings recorded in firm's lessons learned knowledge base

Section 7

CPD Learning Outcomes

Contribute to a Post-Occupancy Evaluation by comparing actual year-1 operational and maintenance costs against the NRM3 lifecycle cost plan and identifying variances at elemental level.
Prepare the cost performance section of a POE report in compliance with RIBA Stage 7 obligations, distinguishing between maintenance costs, energy costs, and defect remediation costs.
Apply POE findings to update the firm's NRM3 lifecycle cost models, feeding actual building performance data back into future estimates and closing the estimating-to-actual feedback loop.

Section 8