What is maintenance?

Building components deteriorate with time or use. At some stage their performance no longer meets a required standard. Maintenance is an intervention so that the component can perform to the required standard.

Maintenance activities are very variable in both time and cost. The range of activities includes visual inspection, testing, cleaning, repairs, replacement and improvement.

Preventative and corrective maintenance

Preventative maintenance involves intervention before performance has fallen below a given standard.

Corrective maintenance involves intervention after performance has fallen below a given standard. Corrective maintenance may also be known as 'responsive maintenance', 'day-to-day maintenance' or 'emergency maintenance'.

Formal maintenance definitions

More detailed and specific definitions of maintenance abound. For example:

• BS 3811:1993, the British Standard for the glossary of maintenance terms, has 16 maintenance definitions including maintenance strategies or types.
• BS EN 13306:2010, the European Standard for maintenance terminology, has 12 definitions of maintenance strategies or types.
• BS ISO 15686-1:2001, the International Standard for service life planning considers 4 types of maintenance activity, namely maintenance, repair, refurbishment and restoration.
• BS 8210:1986, the British Standard for building maintenance management, includes 5 types of maintenance or maintenance activity
• BS 8544:2013, the British Standard for the guide for life cycle costing of maintenance during the in use phases of buildings.

Don't get hung up on definitions. They simply provide a useful framework within which to consider differing strategies and methods to managing the maintenance of assets.

In practice approaches to maintenance depend as much on:

• the buildings and components to be maintained;
• policies;
• structures; and
• resources and finances

as fitting activities into defined types of maintenance.

Planned maintenance

The British Standard for maintenance terms defines planned maintenance as:

'The maintenance organised and carried out with forethought, control and the use of records to a predetermined plan. NOTE: Preventive maintenance is always part of planned maintenance; corrective maintenance may or may not be.' (BS 3811:1993 definition 4114)

This definition is based on that for the British Standard for maintenance management below, 7 years later without the need for condition surveys:

'Maintenance organised and carried out with forethought, control and the use of records, to a predetermined plan based on the results of previous condition surveys.' (BS 8210:1986 definition 1.2.10)

A subsequent European standard relating to maintenance does not include a definition of planned maintenance, but has this definition for preventive maintenance:

'Maintenance carried out at predetermined intervals or according to prescribed criteria and intended to reduce the probability of failure or the degradation of the functioning of an item.' (BS EN 13306:2001 definition 7.1)

Balance between planned and corrective maintenance

A ratio of 70% planned maintenance to 30% corrective maintenance (urgent repairs) was recommended by the Audit Commission (2001) in a report highlighting good practice in the housing sector.

Generally carrying out a series one-off repairs is more costly in the long term than grouping works.