Base construction of buildings
Base construction or ‘base build’ refers to the works done, usually by speculative office building developers, to erect the ‘basic’ elements of a buildings. Once the building is let to tenants they are then given responsibility or the fit out of the interior, that is, making interior spaces suitable for occupation.
‘Base build’ may also be referred to as ‘shell and core’, and typically includes:
- Primary structure.
- Building envelope (roof and façade) in whole or part.
- Mechanical and supply systems (electricity, HVAC, telephone, water, drainage, gas, etc.,), up to the point of contact with individual tenant spaces.
- Public circulation and fire egress areas, such as lobbies, corridors, elevators and public stairs.
Once practical completion of the base build has been finished, the tenant fits out their part of the lettable space. Tenants may be given access prior to practical completion to carry out parts of the works, and may be allowed a rent-free period for the duration of fit out works.
The agreement to lease between landlord and tenant should clearly define who does what, to what standard, and the periods allowed, including:
- What comprises the base build, including space provision in common areas for tenant equipment such as standby generators, extra chillers, or uninterrupted power supply plant.
- What elements of the fit out may be installed by the tenant but funded by the developer/landlord.
- What tenant equipment is to be installed in common areas.
When the tenant takes occupation of the space, it is wise to undertake a conditions survey so that they can notify the developer or landlord of any defects or omissions. It is relatively common that defects in the base construction do not get rectified by the contractors quickly enough for the fit out to be completed. This can lead to the tenant’s contractors making good the defects and then issuing a claim to the base build contractors for the cost of the works.
For more information see: Shell and core.
[edit] Find out more
[edit] Related articles on Designing Buildings Wiki
Featured articles and news
Advancing BIM education with a competency framework
“We don’t need people who can just draw in 3D. We need people who can think in data.”
Guidance notes to prepare for April ERA changes
From the Electrical Contractors' Association Employee Relations team.
Significant changes to be seen from the new ERA in 2026 and 2027, starting on 6 April 2026.
First aid in the modern workplace with St John Ambulance.
Ireland's National Residential Retrofit Plan
Staged initiatives introduced step by step.
Solar panels, pitched roofs and risk of fire spread
60% increase in solar panel fires prompts tests and installation warnings.
Modernising heat networks with Heat interface unit
Why HIUs hold the key to efficiency upgrades.
Reflecting on the work of the CIOB Academy
Looking back on 2025 and where it's going next.
Procurement in construction: Knowledge hub
Brief, overview, key articles and over 1000 more covering procurement.
Sir John Betjeman’s love of Victorian church architecture.
Exchange for Change for UK deposit return scheme
The UK Deposit Management Organisation established to deliver Deposit Return Scheme unveils trading name.
A guide to integrating heat pumps
As the Future Homes Standard approaches Future Homes Hub publishes hints and tips for Architects and Architectural Technologists.
BSR as a standalone body; statements, key roles, context
Statements from key figures in key and changing roles.
ECA launches Welsh Election Manifesto
ECA calls on political parties at 100 day milestone to the Senedd elections.
Resident engagement as the key to successful retrofits
Retrofit is about people, not just buildings, from early starts to beyond handover.
Plastic, recycling and its symbol
Student competition winning, M.C.Esher inspired Möbius strip design symbolising continuity within a finite entity.
Do you take the lead in a circular construction economy?
Help us develop and expand this wiki as a resource for academia and industry alike.
Warm Homes Plan Workforce Taskforce
Risks of undermining UK’s energy transition due to lack of electrotechnical industry representation, says ECA.
Cost Optimal Domestic Electrification CODE
Modelling retrofits only on costs that directly impact the consumer: upfront cost of equipment, energy costs and maintenance costs.