Phase 1 of a multi-unit B2/B8 light industrial estate on a 0.9-hectare former brownfield plot in Knowsley, Merseyside — six identical 280m² steel-portal-frame units built as a single coordinated template, with brownfield remediation under Knowsley MBC Environmental Health validation, an estate infrastructure spine sized for two future phases, a Section 278 highway works package for the new estate access road, and individual concrete yards per unit. Nine-month programme delivered against fixed price; five of six units under offer at practical completion. Tenant fit-out outside our contract, gigabit fibre live on the estate ahead of marketing.
A North West commercial property developer with an established phased-estate model commissioned Phase 1 of a small light industrial estate on a 0.9-hectare former brownfield plot in Knowsley, Merseyside. The site had previously been occupied by a small light-engineering operation that had ceased trading some years earlier; the building was demolished by others before our appointment, leaving slabs, foundations and a significant Made Ground layer. Outline planning consent had been granted for up to 18 light industrial B2/B8 units across three phases; our appointment was for Phase 1, comprising six units totalling 1,680m² GIA, plus the estate infrastructure spine sized for the full masterplan and the Section 278 highway works for the new estate access road.
We were one of three contractors invited to tender. Our bid came in second on price by approximately £19,000 against the leading offer. We won the work because our methodology document was the only one to (a) treat the brownfield remediation as a contractually-defined workstream priced on the inherited Phase 2 site investigation report and validated to the Knowsley MBC Environmental Health remediation strategy, (b) size the estate infrastructure spine for the developer's full three-phase masterplan rather than just for Phase 1 (drainage attenuation, services capacity, estate road sub-base, future-phase service stubs), and (c) build the six identical units as a single coordinated template across overlapping workstreams rather than as six sequential builds — a bid-stage promise we held to, with steel erected across two days, cladding as a single workstream, and the six SR2 slab pours sequenced across two weeks of month six.
Practical completion was certified on the contracted date. Five of the six units were under offer at PC, with the sixth let within four weeks of marketing relaunch. The developer's letting agent reported that the estate's gigabit-fibre-on-day-one specification, individual concrete yards and tenant-flexible shell were the three features cited most often by the small-business tenants who took space. Phase 2 enabling works (foundation excavation against the future phase boundary) were left in a condition fit for direct continuation under a separate Phase 2 contract.
The brief came from the developer's Managing Director and the developer's retained quantity surveyor jointly. Priorities, in their stated order:
A 9-month phased multi-unit estate on a former brownfield plot is a different kind of project from a single-tenant big-box. The six units multiply the coordination by six, the brownfield remediation is a gating workstream that has to be cleared before foundation excavation, and the infrastructure has to be sized for buildings that don't yet have planning consent. Every constraint had a workaround that had to be planned before site possession.
The Phase 2 intrusive site investigation report inherited from the developer logged 1.2-1.8m of Made Ground containing hydrocarbon and heavy-metal contamination from the former light-engineering use, with isolated asbestos-containing material in two test pits. The remediation strategy agreed with Knowsley MBC Environmental Health required removal of the contaminated Made Ground under hazardous-waste tracking, a 600mm clean cover layer over a polythene capillary break membrane on the affected zones, and a validation report demonstrating the pollutant linkage broken. We sub-contracted the remediation on a fixed-price contract; 4,200 tonnes of contaminated Made Ground removed under chain-of-custody. Validation report signed off by Knowsley MBC Environmental Health pre-foundations.
The two competing tenders sized the estate infrastructure for Phase 1 and noted that Phases 2 and 3 would carry a "future infrastructure upgrade allowance". We took the developer's masterplan at face value and sized the drainage attenuation, the electrical incoming, the water and gas mains and the estate road sub-base for the ultimate three-phase loading. Service stubs left at the Phase 2 boundary in cap-and-mark condition. Drainage attenuation tank sized at 145m³ against a Phase 1-only requirement of 52m³. Phase 2 contractor inherits a full-spec spine ready to extend.
Building six small units in sequence consumes nine months and the developer's margin disappears into mobilisation and demobilisation cost. Building them in parallel as a single coordinated template halves the overhead. Steel erected in a single two-day campaign across all six frames using one crane, one erector team and one delivery sequence. Cladding as a single workstream across the full 1,680m². Six SR2 slab pours sequenced across two weeks of month six on a single bay-by-bay programme. Roller-shutter and personnel doors fitted in one week across all six units. Programme efficiency compounded into the 9-month contract date.
The estate access required a new bell-mouth junction off the local distributor road including dropped kerbs, a 12m footway diversion to the south of the access, updated highway lighting and a 2.0m visibility splay against the existing public footway. Knowsley MBC Highways approved the design and our nominated S278 sub-contractor (one of their approved-list contractors) at month one. S278 works held as a parallel sub-contract programme dovetailed against the estate road; completion certified by Knowsley MBC Highways in month 6, well ahead of practical completion.
Speculative B2/B8 estates on a small-business letting model succeed on tenant flexibility rather than on bespoke specification. We delivered each unit as a clean shell: services capped at meter position inside the unit, no internal partitions, no internal ceiling, the slab in unsealed power-floated condition for tenants who would later install racking or workshop layouts. Gigabit fibre pre-cabled to a comms position in each unit; BT Openreach connection live on the estate from month 7 ahead of marketing relaunch.
The developer's letting agency relaunched marketing in month 5 with the steel up, the cladding 80% complete and the estate road sub-base laid — the estate visibly forming as a real building rather than a planning artist's impression. Five of the six units were under offer by the end of month 8; the sixth let within four weeks of practical completion. Building Group's role through marketing: keep the site visually presentable for agency viewings, no muddy access for visiting tenants, no programme slippage that would push back the agent's promised occupancy date.
Multi-unit phased industrial estates succeed or fail on the discipline of the early-stage workstreams — the brownfield remediation, the estate infrastructure sizing, the planning conditions discharge and the S278 — long before the first portal frame goes up. Our approach was built around four governance disciplines and one efficiency discipline.
Brownfield remediation owned end-to-end as a contractual workstream. The two competing tenders treated the brownfield remediation as a "to be confirmed" line subject to validation outcomes. We took the inherited Phase 2 SI report at face value, priced the remediation as a fixed-price sub-contract against the agreed remediation strategy, and held the validation report production as a contractual hold-point before any foundation excavation. 4,200 tonnes of contaminated Made Ground removed under hazardous-waste chain-of-custody. Validation report signed off by Knowsley MBC Environmental Health on the Friday of week 9; foundation excavation started Monday of week 10.
Infrastructure sized for the masterplan, not for Phase 1. The developer's three-phase masterplan was a published document; the planning consent referenced it. The two competing tenders priced Phase 1 infrastructure with a "future infrastructure" provisional sum for Phases 2 and 3. We sized the drainage attenuation, electrical capacity, water and gas mains and the estate road sub-base for the ultimate masterplan loading and stubbed services at the Phase 2 boundary. Phase 2 contractor inherits a fully-spec spine. The developer's quantity surveyor confirmed in their stage-two appointment letter that this was the single largest reason we were appointed.
Six identical units built as a single coordinated template. The Wakefield Distribution Warehouse we delivered earlier in the year was a single 6,200m² building on a single critical path. Knowsley was six 280m² buildings, and the temptation is to run them as six small projects each with their own mobilisation, foundation pour, slab pour and cladding. We built them as one project with six bays. Steel erected in a single 2-day campaign with one crane and one erector team across all six frames. Cladding as a single 1,680m² workstream. Six SR2 slab pours sequenced bay-by-bay across two weeks. Roller-shutter and personnel doors fitted in one campaign across all six units. Programme efficiency compounded into the contracted 9-month date.
Marketing-ready presentation throughout. Speculative estates earn their margin from the lettings, and lettings happen against viewings during construction. We treated the site as a marketing asset from month 5 onwards: tarmacked agency parking, dust-suppressed loading bays, weekly tidy-up walks, no muddy access on viewing days, the estate signage installed in month 7 ahead of marketing relaunch. Five of six units under offer at PC; the sixth let within four weeks.
One hundred and ninety working days from possession of site to practical completion. A brownfield-led mobilisation, six units built as a single coordinated template, and an estate infrastructure spine sized for two further phases that don't yet have planning consent.
Site possession, welfare cabin compound and material storage area established on the eastern boundary against the future Phase 2 line. All pre-commencement planning conditions discharged in writing across the first three weeks: ecology survey sign-off, archaeology desk-based assessment, surface water drainage strategy approval, brownfield remediation strategy formally accepted by Knowsley MBC Environmental Health. Section 278 highway works agreement countersigned with Knowsley MBC Highways and the approved-list S278 sub-contractor confirmed. CDM Principal Contractor handover, F10 notification submitted. Existing slab and foundation breakout commenced.
Brownfield remediation sub-contractor mobilised week one of month two. 4,200 tonnes of contaminated Made Ground removed across the affected zones under hazardous-waste chain-of-custody documentation, with daily air monitoring against asbestos-fibre limits. Capillary break polythene membrane laid across the affected zones. 600mm of imported clean cover material placed and compacted to the developer's geotechnical specification. Validation samples taken on a 25m grid by an independent UKAS-accredited contamination consultant. Validation report compiled and submitted to Knowsley MBC Environmental Health on the Wednesday of month two week four; sign-off received the following Friday.
Bulk earthworks across the platform: 6,800m³ of cut-and-fill within the remediated envelope. Foul drainage 220m to the public sewer connection, surface water drainage 380m to the cellular attenuation tank position. 145m³ cellular attenuation tank installed under the future estate road footprint, sized for the ultimate three-phase masterplan against a Phase 1-only requirement of 52m³. Oil interceptor on the estate road drainage outfall. Foundation pad bases excavated for all six units within the same campaign, services trenches dug for the spine.
RC pad foundations cast for all six unit portal frames in a single sequenced campaign across two weeks. New estate substation built off the developer's electrical capacity agreement, sized for the full three-phase masterplan loading. Estate services spine laid: water mains, gas mains, electrical ducts, BT Openreach ducts, all sized for the ultimate masterplan and stubbed at the future Phase 2 boundary in capped-and-marked condition. Phase 2 contractor inherits a full-spec spine ready to extend.
Steel sub-contractor mobilised on a fixed two-day erection campaign across all six unit frames with a single crane, single erector team and a co-ordinated steel delivery sequence. Day one: three frames erected on the western half of the terrace. Day two: three frames erected on the eastern half. Independent steelwork inspection by a third-party engineer pre-cladding: zero non-conformances logged. Composite roofing system installed across all six units (120mm PIR-cored composite panels, 7% rooflight area in twin-skin GRP rooflights). Wall cladding to walls: 100mm PIR-cored insulated composite panels across the full 1,680m² in a single workstream. Building weather-tight by end of month five. Marketing relaunched by the developer's agent in week four of month five.
Six SR2 power-floated ground-bearing slabs (175mm thickness on 1200-gauge DPM on 50mm sand blinding on Type-1 sub-base) sequenced bay-by-bay across two weeks of month six, with power-trowelling at 6, 12 and 18 hours post-pour. Each unit slab tested to TR34 sixth-edition SR2 by an in-house competent person at 28 days; all six within tolerance. Section 278 highway works completed in parallel: bell-mouth junction off the local distributor, 12m footway diversion, dropped kerbs, updated highway lighting, 2.0m visibility splay. S278 completion certificate issued by Knowsley MBC Highways at the end of month six.
M&E first and second fix across all six units in a single campaign: small power and lighting circuit per unit, three-phase incomer terminated at unit meter position, gigabit fibre pre-cabled to comms position in each unit, BT Openreach connection live on the estate. Roller-shutter and personnel doors fitted across all six units in a single campaign in week three of month seven. LED daylight-linked unit lighting installed and commissioned. Daylight sensors tied to the rooflight zones. Fire alarm and smoke detection installed to BS 5839 Part 1.
Estate road heavy-duty asphalt top-coat laid across the full estate width (sized for the ultimate masterplan, not just Phase 1), line-marked for HGV swept paths, individual unit access strips and the visitor parking with EV charging provision. Six individual concrete yards in front of each unit (60m² each, 360m² total) laid in a single concrete pour with separating precast concrete kerbs. Estate perimeter palisade fencing erected, sliding access gate hung on the new bell-mouth, estate signage installed at the entrance ahead of the agent's tenant viewings. PV-readiness verified on each unit roof.
Final snag round in week one of month nine: 38 items closed by end of week two. Air-permeability test on a representative two-unit sample: results 5.3 and 5.1 m³/(h.m²) at 50Pa, both within the contracted target of less than 6.0. BREEAM assessment by the developer's appointed BRE assessor in week three: 51.8% scoring achieved across the estate average against a contracted target of 50% (Very Good). Practical completion certificate issued on the contracted date. Full O&M manuals, certification reports, brownfield validation report, BREEAM report, S278 completion certificate and warranty package handed over to the developer. Five of six units under offer at PC; sixth unit let within four weeks.
The technical detail behind a 1,680m² multi-unit B2/B8 light industrial estate on a former brownfield plot, built to a tenant-flexible shell specification with infrastructure sized for two further phases.
4,200 tonnes of contaminated Made Ground removed under hazardous-waste chain-of-custody documentation. Daily air monitoring against asbestos-fibre limits during the active works. 600mm imported clean cover layer over a polythene capillary break membrane across the affected zones. Independent validation by UKAS-accredited contamination consultant on a 25m grid. Validation report signed off by Knowsley MBC Environmental Health pre-foundations.
RC pad foundations under each portal frame on Type-1 compacted sub-base over the remediated 600mm clean cover layer. Foundation design verified against the inherited Phase 2 SI report bearing capacity in the underlying glacial till. All six unit foundations cast in a single sequenced campaign across two weeks of month four.
175mm thickness ground-bearing slab on 1200-gauge DPM on 50mm sand blinding on compacted Type-1 sub-base. Power-trowelled finish to TR34 sixth-edition SR2 specification (general light industrial / storage class, not narrow-aisle racking). Six individual slabs sequenced bay-by-bay across two weeks. All six within SR2 tolerance at 28-day in-house test.
Six identical single-span 14m portal frames at 7m centres, 8m clear internal eaves height, 9.2m to apex. Secondary purlins on 1.5m centres. Gable-end frames, eaves beams, longitudinal and gable-frame bracing to current Eurocode wind loadings. All steelwork to BS EN 1090 execution class EXC2. Erected in a single 2-day campaign across all six frames.
Walls: 100mm PIR-cored insulated composite panels across the full 1,680m² in a single workstream, RAL-7016 anthracite finish. Roof: 120mm PIR-cored composite roofing system on standing-seam profile, 7% rooflight area in twin-skin GRP rooflights, motorised smoke vents to fire strategy. Air-permeability sample test result: 5.3 and 5.1 m³/(h.m²) against target less than 6.0.
One up-and-over insulated sectional roller-shutter loading door per unit (4m wide x 4m high), motorised with internal control panel and external manual key-bypass. One insulated personnel access door per unit on the front elevation. Both fitted across all six units in a single one-week campaign.
Six 60m² concrete yards (360m² total) in front of each unit, separated by precast concrete kerbs. Yard surface: 200mm reinforced concrete on Type-1 sub-base, line-marked for tenant van or small-vehicle parking and loading. Single concrete pour across all six yards in month eight.
145m³ cellular attenuation tank under the estate road, sized for the developer's ultimate three-phase masterplan against a Phase 1-only requirement of 52m³. Oil interceptor on the estate road drainage outfall. Foul drainage 220m to public sewer connection. Surface water drainage 380m to attenuation tank. Service stubs left at the Phase 2 boundary in cap-and-mark condition.
Water mains, gas mains, electrical ducts and BT Openreach ducts laid under the estate road, all sized for the ultimate masterplan loading and stubbed at the Phase 2 boundary. New estate substation provisioned for the full three-phase masterplan electrical capacity. Gigabit fibre pre-cabled to comms position in each unit; BT Openreach connection live on the estate from month seven.
Heavy-duty asphalt overlay on a fully-bound base course across the full estate road width (ultimate masterplan width, not Phase 1 only). Section 278 highway works: bell-mouth junction off the local distributor, 12m footway diversion, dropped kerbs, updated highway lighting, 2.0m visibility splay. S278 completion certificate issued by Knowsley MBC Highways month six.
BREEAM Very Good achieved at 51.8% across the estate average against contracted 50% target. PV-ready roof structure on each unit (panel weights and electrical infrastructure provisioned for future tenant install), EV charging provision at the visitor parking, daylight-linked LED lighting in each unit. Air-permeability sample test 5.3 m³/(h.m²).
Estate perimeter palisade fencing (2.4m height) with anti-climb topping. Sliding access gate on the new bell-mouth junction, CCTV mast-points pre-cabled at the perimeter for tenant or developer-installed cameras. Fire alarm and smoke detection in each unit to BS 5839 Part 1.
A 1,680m² multi-unit B2/B8 light industrial estate on a former brownfield plot in Knowsley delivered against a 9-month fixed-price contract with no variation orders, the brownfield validation samples passing first-time across the full 25m grid, all six SR2 slab pours within tolerance, the BREEAM Very Good target exceeded at 51.8%, the Section 278 highway works completed a full month ahead of programme, and zero RIDDOR-reportable accidents across 64,000 contract hours. Practical completion was certified on the contracted date. Five of the six units were under offer at PC; the sixth let within four weeks of marketing relaunch.
The estate infrastructure spine was sized for the developer's full three-phase masterplan rather than just for Phase 1. The 145m³ cellular attenuation tank, the new estate substation, the water and gas mains, the electrical ducts and the BT Openreach ducts were all laid to ultimate-masterplan capacity with services stubbed at the Phase 2 boundary in cap-and-mark condition. The Phase 2 contractor (whoever the developer appoints when planning consent for Phase 2 is granted) inherits a full-spec spine ready to extend rather than a Phase 1 build that needs upgrading. The Wakefield Distribution Warehouse we delivered earlier in the year was a single big-shed on a single critical path; this one was the same methodology applied to six small units coordinated as a single template, on a brownfield site, for a developer running a phased speculative model.
We are a North West commercial property developer running a phased speculative model on small light industrial estates. Knowsley was a brownfield plot we had under option for two years before we got planning. We tendered three contractors. Building Group came in second on price by nineteen thousand pounds. We appointed them because their methodology document was the only one to price the brownfield remediation as a fixed-price sub-contract against the inherited Phase 2 site investigation and the agreed Knowsley Environmental Health remediation strategy, the only one to size the estate infrastructure spine for our full three-phase masterplan rather than just for Phase 1, and the only one to commit to building the six units as a single coordinated template across overlapping workstreams rather than as six sequential builds. The cheaper bid would have hit us with a brownfield variation in month two and an infrastructure variation in month four. Nine months later we had six units up, the brownfield validation closed off with the council, BREEAM Very Good achieved at fifty-one point eight per cent, the Phase 2 service stubs in cap-and-mark condition for whoever we appoint next, five of six units under offer at practical completion and the sixth let within four weeks. We have already appointed them on Phase 2 of the same scheme.
If you're a developer with a brownfield plot under option, an investor running a phased speculative model, or a landowner looking at a small light industrial scheme, we'll come out for a free site visit, walk the site investigation report and the planning consent with your managing director and quantity surveyor, and put a fixed-price methodology document on your desk — with the brownfield remediation, the estate infrastructure sized for the full masterplan, the Section 278 highway works and the BREEAM scoring strategy all costed in.
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