29th August 2026
Key facts from the documents
- Site area: approximately 1.8 hectares.
- Primary technique actually used: engineered clean cover system (minimum 400 mm of validated topsoil/subsoil + geotextile/capillary break) across soft landscaping and sports pitch areas, plus localised asbestos hand-picking/removal and gas-protection membranes in the buildings.
- Full deep excavation and off-site disposal of the entire made ground (up to 7 m thick in places) was not carried out.
- The £9.94 million figure noted by the Executive in March 2008 was before the full contamination was publicly admitted and the main remediation works were finalised.
Cost estimate
| Element | Estimated cost range (2010–2011 prices) | Notes |
|---|---|---|
| Engineered cover system (≈1.0–1.3 ha of soft areas) | £250,000 – £550,000 | 400–500 mm clean imported material + geotextile. Typical cover-system rates at the time were roughly £20–£45/m². |
| Localised asbestos management & hand-picking | £80,000 – £250,000 | Highly variable; depends on volume of affected material. Hand-picking and licensed disposal of asbestos-contaminated soils is expensive. |
| Gas-protection measures in buildings | £40,000 – £100,000 | High-spec DPM + detailing on concrete slabs. |
| Validation testing, supervision & verification reporting | £40,000 – £80,000 | Required for regulatory sign-off. |
| Contingency / unforeseen hotspots | £50,000 – £150,000 | Common on former tips. |
| Total estimated remediation cost | £460,000 – £1.13 million | Most likely mid-range: £650,000 – £900,000 |
How this sits with the overall project cost
- Early scheme estimates: ~£5.5 million.
- March 2008 Executive figure: £9.94 million (already a major increase, largely from design, CPO, inflation, Sport England requirements, etc.).
- Final out-turn was higher still once the cover system, asbestos works and delays were added.
A remediation bill in the £0.65–0.9 million range (at 2010/11 prices) is consistent with:
- The chosen “cover and contain” strategy rather than full dig-and-dump.
- The site size (1.8 ha).
- Contemporary UK benchmark rates for cover systems on high-sensitivity (school) end-uses.
- The fact that the big jump to £9.94 million occurred before the main contamination works were fully scoped and executed.
If the Council had chosen widespread excavation and off-site disposal of the made ground, the remediation cost would have been several times higher (potentially £2–4 million+), but that is not what the verification reports show was done.
Note: These are reasoned estimates based on the documented technique, site area, and typical 2009–2011 UK rates. Exact figures would only be available from the final account / BAM Construction records or Stockport Council’s project file.
