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.

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[edit] Related articles on Designing Buildings Wiki

• Advantages of shell and core.
• Capital allowances.
• Client commissioning.
• Defects liability period.
• First fix.
• Fit out of buildings.
• Handover to client.
• Practical completion.
• Rent free period.
• Shell and core.
• Soft landings.