What are Integral Features?

The rules on integral features were introduced in April 2008. Integral features are classed within the Capital Allowances Act 2001 (CAA01) as Plant & Machinery (P&M) and as such attract capital allowances.

CAA01 classes the following as an integral feature of a building or structure –

  • an electrical system (including a lighting system),
  • a cold water system,
  • a space or water heating system, a powered system of ventilation, air cooling or air purification, and any floor or ceiling comprised in such a system,
  • a lift, an escalator or a moving walkway,
  • external solar shading

Only assets that are on the list are integral features for P&M allowances purposes.

The rules also specifically clarify that the new definition does not extend to any asset whose principal purpose is to insulate or enclose the interior of a building, or to provide interior walls, floors or ceilings which are intended to remain permanently in place (S23(4) & S33A(6)). So if, for example, a business installs a new, permanent false ceiling in its premises, in order to conceal new wiring and service pipes, expenditure on that ceiling would not qualify for P&M allowances.

On the other hand, if a business installs in its premises a plenum floor or plenum ceiling, the principal purpose of which is to function as an integral part of the heating or air conditioning system (for example, the plenum floor or plenum ceiling may form the fourth side of a duct or channel through which stale air is extracted and treated air is discharged), that expenditure would qualify for PMAs as part of an ‘integral feature’ of the building or structure (CA22070 & CA22080).

Special 10% rate of Writing Down Allowances (WDAs)

Integral features are defined as  ‘special rate expenditure’, which must be allocated to the ‘special rate pool’ and in respect of which the person incurring the expenditure may be entitled to WDAs at the ‘special rate’ of 10% p.a. (reduced to 8% as from April 2012).  Expenditure on the provision or replacement of integral features is one type of special rate expenditure. Other types are expenditure on thermal insulation and expenditure on long-life assets.


When undertaking a claim for capital allowances it is therefore important to determine when expenditure was incurred. This is to  determine whether certain “fixtures”  qualify as integral features and should therefore be allocated to the “special rate pool”.  Alternatively where the expenditure on “fixtures” was incurred before April 2008 it may therefore qualify for the “main pool”  where the WDAs were 20% p.a. (reduced to 18% as from April 2012)

The capital allowances legislation was changed in an effort to help define more closely those features which do qualify for capital allowances as CAA01 does not contain a definitive list of items which qualify as P&M.