Choose your delivery model
This shapes how the Interlayer assembles your team and structures your contracts
Turnkey — single contractor
One lead contractor takes full responsibility for design, procurement and delivery. Single point of accountability with a single contract.
Single contract Design & Build JCT D&B / NEC4 Lower admin
✓ Selected
Assembled team — sub-contractors
The Interlayer curates specialist sub-contractors per trade. Greater transparency, competitive pricing per discipline and direct visibility of each trade's costs.
Per-trade contracts Separate quotes JCT Minor Works Full cost control
Turnkey mode: The Interlayer will seek a single lead contractor who manages all sub-contractors and delivers the project end-to-end. You will receive 3 competitive bids.
Project identity & location
Project definition
Construction type — tick all that apply
Sustainability & compliance requirements
Trades required
Special requirements
Budget & programme
Competing bids per main contractor
3
contractor bidsScoring criteria
Drag to adjust weighting
AI will interpret your brief and generate an editable project definition
Turnkey mode — AI will seek a single lead contractor
AI Interlayer — project definition
Review and edit before submitting to seek quotes
AI material recommendations
Structural steel frame
S355 hot-rolled · CE marked · 3 local suppliers
Brick-faced cavity wall
Buff brick to match existing · U-value ≤0.18 W/m²K
TPO warm flat roof
200mm PIR · single-ply membrane · 25yr warranty
PV array (28kWp roof-mounted)
Supports BREEAM Excellent credits
ASHP + MVHR ventilation
Air source heat pump · heat recovery · Part L compliant
Budget breakdown (AI estimate)
AI notes
Benchmark rate of £2,850/m² gives a construction cost estimate of £2.39M. Your total budget of £4.1M is above benchmark — the surplus covers professional fees (~12%), surveys, planning and a healthy 10% contingency. The Interlayer will seek 3 competitive quotes to validate.
Turnkey mode — 3 lead contractor bids returned
Score cards
Side-by-side compare
MC
Mitchell Contracts Ltd
⭐ AI recommended Best overallMain contractor · Guildford, Surrey · 4 miles from site
Total bid
£3,820,000
£280K under budget
91
Design & mgmt
£284,000
Groundworks
£890,000
M&E services
£620,000
Finishes & fit-out
£740,000
External works
£180,000
Prelims & OHP
£1,106,000
Proposed programme
CB
Crestwood Build Ltd
2nd placeMain contractor · Woking, Surrey · 11 miles from site
Total bid
£3,940,000
£160K under budget
76
SS
Southern Structures
3rd placeMain contractor · Crawley, W. Sussex · 24 miles from site
Total bid
£4,180,000
£80K over budget
58
AI recommendation
Mitchell Contracts scores best across all four criteria — lowest price, shortest programme, highest sustainability credentials, closest to site. Accepting saves £360,000 versus the highest bid.
Bid range
Lowest bid
£3,820,000
Highest bid
£4,180,000
Spread
£360,000
Programme comparison
Mitchell Contracts
11 months
Crestwood Build
12 months
Southern Structures
13 months