The term 'capital allowances' is used to describe the allowances available to businesses to secure tax relief for certain capital expenditure. The rules that govern the purchase of capital equipment such as computer equipment, vehicles and machinery by businesses are different to those for day to day business expenses that can be deducted from business income when calculating your taxable profits.

However, the fact that capital allowances have been given on the asset as a whole does not prevent a revenue deduction being made for a repair to that asset.

There are special rules for assets that are ‘integral features’. 

Integral features are:

• electrical systems, including lighting systems
• hot and cold water systems (but not toilet and kitchen facilities)
• space and water heating systems
• air-conditioning and air cooling systems
• lifts, escalators and moving walkways
• external solar shading

In general, where the expenditure on an integral feature represents 50% or more of the cost of replacing the integral feature, then the whole of the expenditure is to be treated as capital expenditure on the replacement of an integral feature for capital allowances purposes.