What Is an Interim Valuation in Construction? Payment Cycle

<div class="ge-article-wrapper"><nav class="ge-toc" aria-label="Table of contents"><p class="ge-toc-label">In this article</p><ul class="ge-toc-list"><li><a href="#how-the-valuation-cycle-works">How the Valuation Cycle Works</a></li><li><a href="#what-gets-valued">What Gets Valued</a></li><li><a href="#linking-interim-valuations-to-earned-value">Linking Interim Valuations to Earned Value</a></li><li><a href="#worked-example-monthly-valuation-with-ev-overlay">Worked Example: Monthly Valuation With EV Overlay</a></li><li><a href="#common-mistakes">Common Mistakes</a></li><li><a href="#frequently-asked-questions">Frequently Asked Questions</a></li></ul></nav><article class="ge-article-body"><p>An interim valuation is a periodic assessment of the work completed on a construction project, used to determine how much the contractor should be paid. On most UK contracts, it happens monthly. On NEC4, it's tied to the assessment date defined in Contract Data Part 1, and that date triggers a chain of deadlines that, if missed, puts the client in breach. Not "a bit late." In breach. </p><p>Interim valuations are where <a href="/en/earned-value">earned value management</a> and commercial reality collide. Every month's valuation is a data point: what's been done, what it cost, and how that compares to the plan. If you're running EVM on a construction project, your interim valuation is also your primary source for <a href="/en/earned-value/definitions/actual-cost">Actual Cost (AC)</a> and a cross-check on <a href="/en/earned-value/definitions/earned-value">Earned Value (EV)</a>. </p><p>This page is part of the <a href="/en/earned-value/definitions">earned value definitions glossary</a>. </p><h2 id="how-the-valuation-cycle-works">How the Valuation Cycle Works</h2><p>The process differs by contract form, but the mechanics are universal: someone measures the work, someone certifies the amount, and someone pays. The devil is in the deadlines. </p><pre class="ge-ascii-diagram ge-anim"> MONTHLY VALUATION CYCLE (NEC4 Option C) ========================================= Week 1 Week 2 Week 3 Week 4+ ────────────────────────────────────────────────────────────────── ASSESSMENT PM ASSESSES PAYMENT PAYMENT DATE THE AMOUNT CERTIFICATE DUE DATE (Contract Data) DUE ISSUED (PWDD) │ │ │ │ │ Contractor │ PM calculates │ Certificate │ Client │ submits │ the Price for │ states amount │ must pay │ application │ Work Done to │ due, basis of │ the amount │ (recommended, │ Date (PWDD) │ calculation │ certified │ not required │ │ │ │ under NEC4) │ │ │ ▼ ▼ ▼ ▼ Day 0 Day 7* Day 7* Day 21* (within 1 week (with the (3 weeks after of assessment) assessment) assessment date) * Exact periods depend on Contract Data entries. The periods shown are typical but contractual. ┌─────────────────────────────────────────────────────────┐ │ CRITICAL: Under clause 51.2, if the PM doesn't │ │ certify a payment within 1 week of the assessment │ │ date, the Contractor's own application becomes the │ │ certified amount by default. That's the ratchet. │ └─────────────────────────────────────────────────────────┘ COMPARISON: JCT vs NEC4 PAYMENT MECHANISMS JCT (DB 2024) NEC4 (Option C) ───────────── ──────────────── Contractor submits Assessment date triggers an application (required) the process (application not contractually required) ↓ ↓ Employer issues payment PM assesses and certifies notice within 5 days within 1 week of assessment ↓ ↓ Payment due 14 days Payment due 3 weeks after from due date assessment date (PWDD) ↓ ↓ Pay less notice PM can assess a different required to reduce amount – no separate pay less notice needed </pre><h2 id="what-gets-valued">What Gets Valued</h2><p>This is where people trip up. An interim valuation isn't the contractor's wish list. It's an assessment of what's been done and what's owed under the contract terms. </p><p>On NEC4 Option C (target cost), the valuation includes: </p><div class="ge-table-wrap ge-anim"><table class="ge-table"><thead><tr><th>Component</th><th>What It Covers</th><th>Where It Comes From</th></tr></thead><tbody><tr><td>Defined Cost</td><td>Actual cost of People, Equipment, Plant and Materials, Subcontractors, charges</td><td>Contractor's records, invoices, timesheets</td></tr><tr><td>Fee</td><td>Subcontractor fee + direct fee percentage</td><td>Contract Data Part 2</td></tr><tr><td>Implemented CEs</td><td>Adjustment to the Prices for compensation events</td><td>CE quotations accepted or PM assessments</td></tr><tr><td>Disallowed Cost</td><td>Deductions for costs not properly incurred</td><td>PM's assessment under clause 11.2(26)</td></tr><tr><td>Retention</td><td>Held against defects (if Z clause applies)</td><td>Contract-specific</td></tr></tbody></table></div><p>On NEC4 Option A (priced contract with activity schedule), the valuation is simpler: the PM assesses which activities on the activity schedule are complete. Partially complete activities don't count unless the contract says otherwise. This creates a lumpy cash flow that frustrates contractors, you can be 90% through an activity and get paid nothing until it's finished. </p><h2 id="linking-interim-valuations-to-earned-value">Linking Interim Valuations to Earned Value</h2><p>Here's what most EVM guides miss. On a UK construction project, the interim valuation is your richest data source for earned value metrics. </p><div class="ge-table-wrap ge-anim"><table class="ge-table"><thead><tr><th>EVM Metric</th><th>Valuation Link</th></tr></thead><tbody><tr><td><a href="/en/earned-value/definitions/actual-cost">Actual Cost (AC)</a></td><td>Defined Cost to date (Option C) or cost-loaded actuals (Option A)</td></tr><tr><td><a href="/en/earned-value/definitions/earned-value">Earned Value (EV)</a></td><td>Value of completed work, measured against <a href="/en/earned-value/definitions/budget-at-completion">BAC</a></td></tr><tr><td><a href="/en/earned-value/definitions/planned-value">Planned Value (PV)</a></td><td>Cumulative budget from the Accepted Programme at the assessment date</td></tr></tbody></table></div><p>The alignment isn't always clean. AC from the valuation includes fee, which may or may not be in your EVM baseline. And EV measurement methods (milestones, percent complete, 0/100) can differ from the valuation method (activity completion or Defined Cost). But the valuation gives you the financial ground truth. Any EVM system that diverges significantly from the valuation data needs investigating. </p><p>I've worked on projects where the EVM report said CPI was 0.92 and the CVR (derived from valuations) showed margin at 4.2%. Both can't be right. The disconnect was that the EVM system was using tender rates as the cost baseline while the valuation used actual Defined Cost. Reconciling the two took a week. But after that, the commercial team had one set of numbers they trusted. </p><h2 id="worked-example-monthly-valuation-with-ev-overlay">Worked Example: Monthly Valuation With EV Overlay</h2><span class="ge-worked-label">Worked Example</span><div class="ge-callout ge-anim"><p><strong>Scenario:</strong> A £16M NEC4 Option C school extension in Bristol. Assessment date: 7th of each month. At the month 6 assessment (7 September 2025):</p><br><p><strong>Valuation Build-Up:</strong></p><br><div class="ge-table-wrap ge-anim"><table class="ge-table"><thead><tr><th>Item</th><th>This Period</th><th>Cumulative</th></tr></thead><tbody><tr><td>People (site team, direct labour)</td><td>£185,000</td><td>£1,120,000</td></tr><tr><td>Subcontractors (paid)</td><td>£480,000</td><td>£2,890,000</td></tr><tr><td>Subcontractors (accrued, not yet invoiced)</td><td>£120,000</td><td>£120,000</td></tr><tr><td>Plant and Equipment</td><td>£95,000</td><td>£610,000</td></tr><tr><td>Materials on site</td><td>£60,000</td><td>£340,000</td></tr><tr><td><strong>Defined Cost subtotal</strong></td><td><strong>£940,000</strong></td><td><strong>£5,080,000</strong></td></tr><tr><td>Fee (11% on subcontractors, 8% on direct)</td><td>£82,000</td><td>£463,000</td></tr><tr><td><strong>Amount Due (before retention)</strong></td><td><strong>£1,022,000</strong></td><td><strong>£5,543,000</strong></td></tr><tr><td>Less: previously certified</td><td></td><td>-£4,521,000</td></tr><tr><td><strong>Payment this period</strong></td><td></td><td><strong>£1,022,000</strong></td></tr></tbody></table></div><br><p><strong>EV Overlay (same status date):</strong></p><br><div class="ge-table-wrap ge-anim"><table class="ge-table"><thead><tr><th>Metric</th><th>Value</th><th>Source</th></tr></thead><tbody><tr><td>BAC</td><td>£16,000,000</td><td>Target total of the Prices (including 3 implemented CEs)</td></tr><tr><td>PV (cumulative)</td><td>£5,920,000</td><td>From Accepted Programme at 7 Sept</td></tr><tr><td>EV (% complete x BAC)</td><td>£5,440,000</td><td>34% physically complete</td></tr><tr><td>AC (Defined Cost + Fee)</td><td>£5,543,000</td><td>From valuation above</td></tr><tr><td><a href="/en/earned-value/definitions/cost-performance-index">CPI</a></td><td>0.981</td><td>£5.44M / £5.543M</td></tr><tr><td><a href="/en/earned-value/definitions/schedule-performance-index">SPI</a></td><td>0.919</td><td>£5.44M / £5.92M</td></tr><tr><td><a href="/en/earned-value/cost-schedule-variance">CV</a></td><td>-£103,000</td><td>Minor cost overrun</td></tr><tr><td><a href="/en/earned-value/cost-schedule-variance">SV</a></td><td>-£480,000</td><td>Behind programme</td></tr></tbody></table></div><br><p><strong>Interpretation:</strong> Cost performance is nearly on target (CPI 0.98) but schedule is lagging (SPI 0.92). The valuation shows the project is spending about right per unit of work, but there isn't enough work in the ground. The commercial manager flags the schedule issue to the project manager. Cause: delayed steelwork delivery pushed the structural frame back by 3 weeks. Recovery programme being developed.</p></div><h2 id="common-mistakes">Common Mistakes</h2><p><strong>Conflating the application with the assessment.</strong> On NEC4, the contractor's application is not the interim valuation. It's a submission for the PM to consider. The PM's assessment is the valuation. If the PM disagrees with the application, they assess a different figure. The Contractor can dispute it, but the certified amount is what gets paid. </p><p><strong>Missing the assessment date deadline.</strong> This is the one that costs money. Under clause 51.2, if the PM doesn't assess by the assessment date, the Contractor's own assessment becomes the default. I've seen a client overpay by £340K in a single month because the PM's team was on holiday and nobody assessed. That money had to be recovered through the next valuation, but the cash flow damage was done. </p><p><strong>Not accruing subcontractor costs.</strong> A valuation that only includes paid invoices understates AC. Work done but not yet invoiced still needs to be in the valuation. On NEC4 Option C, Defined Cost includes amounts due to subcontractors regardless of whether they've invoiced yet. Miss this and your CPI looks artificially good. </p><p><strong>Valuing materials on site incorrectly.</strong> Materials stored on site but not yet incorporated into the works should be included in Defined Cost (clause 11.2(23)) but only if they've been delivered to the Working Areas. Materials in a supplier's yard don't count. I've had arguments about this that lasted longer than the delivery itself. </p><div class="ge-product-note ge-anim"><p><strong>How Gather helps.</strong> Gather's AI reads your site diaries daily and maps progress against your cost-loaded programme, giving you accurate earned value data without manual spreadsheet updates. <a href="https://gatherinsights.com/contact">Book a demo</a> to see it working on a live NEC4 project.</p></div><h2 id="frequently-asked-questions">Frequently Asked Questions</h2><h3>What's the difference between an interim valuation and a final account?</h3><p>An interim valuation assesses work done to date and results in a periodic payment. The final account is the total cost assessment at completion. It settles everything, including all compensation events, retention releases, and any disputed amounts. Interim valuations are on account; the final account is definitive. </p><h3>How does the assessment date affect payment timing?</h3><p>On NEC4, the assessment date starts the clock. The PM must assess within the period stated in Contract Data (typically one week). Payment is due three weeks after the assessment date (the Payment Due Date). Late payment incurs interest under clause 51.4. Get the assessment date wrong and the entire payment chain shifts. </p><h3>Can the PM reduce a previous valuation?</h3><p>Yes. If the PM over-assessed in a previous month, the correction appears in the next assessment. The cumulative amount due is recalculated, and the difference between the new cumulative figure and what's already been paid determines the current payment. This can result in a negative payment, the contractor owing money back, though in practice this is rare and usually negotiated. </p><h3>How do interim valuations work on NEC4 Option A?</h3><p>On Option A, the PM assesses which activities in the activity schedule are complete and sums their prices. Partially complete activities are assessed at zero unless a Z clause allows partial payment. This means cash flow can be lumpy, a contractor might do 80% of the work in a period and get paid for only 40% because the completed activities don't include the big-ticket item they're mostly through. </p></article></div>