UK · Updated 2026 · Explainer
Part Z & Embodied Carbon: Using Surplus Reclaimed Slate Roof Tiles in Portsmouth
Whole-life carbon assessments are becoming mandatory on Portsmouth projects. Reclaimed and surplus slate tiles is the fastest lever for reducing A1–A3 embodied carbon in South East. This 2026 guide shows the numbers and the evidence you need.
Embodied carbon savings
Reclaimed slate tiles typically avoids 60–95% of the A1–A3 embodied carbon of a new equivalent. On a mid-size Portsmouth project this can equal 4–12 tonnes CO₂e avoided.
Part Z timeline and what it requires
- Whole-life carbon assessment on all major projects
- Reporting to a central UK register
- Alignment with RICS WLCA methodology
- Evidence of material provenance
Building a compliant evidence pack in Portsmouth
- Yard invoice with weight/quantity
- Photos and batch references
- Manufacturer EPD comparison for baseline
- Site delivery notes
Cost of slate tiles vs carbon benefit
| Grade | Typical price | Notes |
|---|---|---|
| Job-lot / bulk | £45 per m² | Merchant clearance, palletised |
| Standard graded | £70 per m² | Sorted, ready-to-fit stock |
| Heritage / premium | £95 per m² | Character grade, hand-picked |
Embodied carbon: Reclaimed Slate Roof Tiles in Portsmouth vs new
Choosing surplus or reclaimed slate tiles in Portsmouth avoids the A1–A3 manufacturing emissions of newly produced stock. On a typical Portsmouth project this equates to roughly 4–8 kgCO₂e per m² — material evidence under Part Z, RICS WLCA and BREEAM Mat 06.
South East local authorities increasingly request whole-life carbon evidence on planning submissions above 1,000 m². Keeping the yard invoice, batch photos and a provenance note against every slate tiles purchase inside PO1, PO4 and PO5 builds an audit trail that stands up to WLCA review.
- A1–A3 avoided: ~4–8 kgCO₂e per m²
- A4 (transport): actual mileage from the Portsmouth yard to site
- A5 (installation): identical to new — labour and fixings unchanged
- Circularity indicator: 1.0 for reclaimed, 0.7–0.9 for surplus new
Expert tips from South East trades
- Buy the whole pallet even if you only need 80% — you'll offload the rest on SurplusBuilder inside 14 days at 60–80% of what you paid.
- Book a Friday collection slot: Portsmouth yards are quieter and forklift drivers have time, so you avoid the PO1, PO4 and PO5 weekday delivery crush.
- Ask for the yard's "just arrived" list — the best slate tiles moves before it hits public listings.
- Photograph everything on the vehicle before you leave — protects both parties if a defect surfaces on unloading.
VAT, warranty and paperwork in Portsmouth
Reclaimed materials from private sellers are typically zero-rated for VAT. Surplus stock from VAT-registered South East merchants carries standard 20% VAT — confirm before agreeing a price. Factory-fresh surplus retains its original manufacturer warranty when unregistered and stored correctly; keep the batch label and any BBA certificate alongside the invoice.
- Get a VAT invoice for surplus buys over £250 — it's deductible for trade
- Retain BBA / BS EN test certificates with the delivery note
- Photograph batch numbers on slate tiles packaging for retrofit and Part L evidence
- Log the Portsmouth postcode of the source yard against the project record
Frequently asked questions
+Is Part Z law yet?
Not yet fully — it's a private-members bill and industry alignment. Adoption on public and BREEAM projects is already widespread.
+How is carbon quantified for surplus?
A1–A3 emissions are usually set to zero for genuine reclaim; A4 (transport) uses actual distance.
+Can I mix reclaimed sizes?
Diminishing courses are traditional — mixing sizes is often historically correct.
+Is surplus slate tiles covered by manufacturer warranty in Portsmouth?
Yes for factory-fresh over-orders and cancelled-order stock. The warranty runs from date of manufacture (batch label) rather than date of purchase — check the batch date before committing on large South East orders.
+Can I count reclaimed slate tiles towards BREEAM Mat 06?
Yes — reclaimed materials attract full circularity credits under BREEAM Mat 06 and RICS WLCA. Keep provenance photos, yard invoice and transport mileage from Portsmouth as evidence.
+What insurance sits behind a SurplusBuilder deal in South East?
Verified sellers carry public liability and product-liability cover. Pallet-network deliveries insure to £1,300/pallet by default; declare higher values for premium slate tiles loads.