Explanatory notes for use with Key & Supplementary On-Costs Tables


TCI are inclusive of the on-costs contained in the relevant on-cost table. The on-costs vary according to the general purpose of the scheme.  TCI levels are set with the assumption that Associations’ development and administrative costs will be contained within the percentages in the relevant on-cost table.

Note. The scheme on-cost selections should be consistent with the scheme multiplier selections. 

Key On-Costs

One Key On-Cost will apply per scheme - to this must be added any appropriate supplementary on-cost.

The appropriate Key or Supplementary On-Cost is determined by the predominant dwelling type in a scheme.  Where two dwelling types are relatively equal, predominance is established by the largest number of persons in total. 

Supplementary On-Costs

Supplementary On-Costs may be used when the accommodation is designed to meet the relevant standards set out in the Design Standards Guide. Two supplementary On-Costs from items A to D may be equally applicable. Only one of these may be applied to a scheme and the higher must be used exclusively. The exception is a design and build (CT) competitive tender contract scheme (see below).

Supplementary on-costs, items E to G may each be added as applicable. Clarification on some of the on-costs is provided below. Please reference others against the relevant multiplier explanatory notes.

More information on:

(e) Design & Build (CT) Contracts

Where the main contractual responsibility for design rests with the contractor, the design & build supplementary on-cost must always be used. If another supplementary on-cost applies the design & build contract on-cost is also used.
For more information see Scheme Types

(f) BREEAM Award or Code for Sustainable Homes Award

The BREEAM Award or the Code for Sustainable Homes Award Supplementary On-Cost is used where the scheme will be designed to meet either award as set out in the Design Standards Guide.

(g) Tenanted/Decanting dwelling

This on-cost multiplier is used where an existing tenant has to be decanted to temporary accommodation – such as another dwelling, mobile home or caravan – until the new build, rehabilitated or re-improved dwelling is completed.*

*(Note: in schemes where existing tenants have to be decanted but where this supplementary multiplier would not automatically apply due to the predominance rule, the NIHE (DPG) may agree to this multiplier being applied at its discretion).

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