Industrial Buildings Allowance (IBA)
|
The Industrial Buildings Allowance (IBA) was introduced by the government in its 1945 Income Tax Act to boost post-war productivity in industry. The idea was that whatever the capital cost of constructing a manufacturing or processing building (or sometimes purchasing it 'second-hand’), the person holding 'the relevant interest' in the building would receive tax relief.
Aimed originally at productive industry, the scope of IBA was broadened to include allowances on infrastructure such as tunnels, bridges, roads used for highway concessions, qualifying hotels and commercial buildings in enterprise zones.
In effect, IBA was a writing down allowance (WDA) – allowing relevant business people to deduct a percentage of the value of an item from their profits each year, which in turn meant they paid less tax – typically for around 25 years, sometimes less. Thus, IBA constituted an incentive to build ‘industrial’ facilities.
However, the item had to count as ‘qualifying expenditure’ that had been incurred on a building.
IBA was made to the person holding relevant interest in relation to the qualifying expenditure. The relevant interest is defined by the construction expenditure incurred on the building; relevant interest therefore is the interest in the building to which the person who incurred the construction expenditure was entitled to when the expenditure was incurred. A building may have had several relevant interests, as construction expenditure could have been incurred at different times and by different people.
The following is an example of relevant interest given by UK tax collection service Her Majesty’s Revenue and Customs (HMRC, formerly ‘Inland Revenue’ for income tax collection):
"Warren builds a factory on land that he owns. The relevant interest for the factory is the freehold interest. If Warren leases the factory to Lowell and Lowell builds an extension, the relevant interest for the extension is Lowell’s leasehold interest. So, there are two relevant interests for the factory – Warren’s freehold interest for the factory and Lowell’s leasehold interest for the extension."
Buildings or constructions that qualified were:
- Buildings of a qualifying trade: e.g manufacturing/processing, storage, generating/transforming/converting, transmitting electrical energy
- Supplying water for public consumption
- Providing sewage undertakings
- Transport, inland navigation and dock undertakings (dock, wharf, pier etc)
- Tunnels
- Bridges (only if expenditure incurred after end 1956-57)
- Highways
- Undertakings for the supply of hydraulic power.
IBA allowances no longer exist. They were continuously in force from 1945 to 2008, after which they became the subject of a phased withdrawal until the financial year beginning April 1, 2011. Since then there have been no IBA writing down allowances.
[edit] Related articles on Designing Buildings
Featured articles and news
What they are, how they work and why they are popular in many countries.
Plastic, recycling and its symbol
Student competition winning, M.C.Esher inspired Möbius strip design symbolising continuity within a finite entity.
Do you take the lead in a circular construction economy?
Help us develop and expand this wiki as a resource for academia and industry alike.
Warm Homes Plan Workforce Taskforce
Risks of undermining UK’s energy transition due to lack of electrotechnical industry representation, says ECA.
Cost Optimal Domestic Electrification CODE
Modelling retrofits only on costs that directly impact the consumer: upfront cost of equipment, energy costs and maintenance costs.
The Warm Homes Plan details released
What's new and what is not, with industry reactions.
Could AI and VR cause an increase the value of heritage?
The Orange book: 2026 Amendment 4 to BS 7671:2018
ECA welcomes IET and BSI content sign off.
How neural technologies could transform the design future
Enhancing legacy parametric engines, offering novel ways to explore solutions and generate geometry.
Key AI related terms to be aware of
With explanations from the UK government and other bodies.
From QS to further education teacher
Applying real world skills with the next generation.
A guide on how children can use LEGO to mirror real engineering processes.
Data infrastructure for next-generation materials science
Research Data Express to automate data processing and create AI-ready datasets for materials research.
Wired for the Future with ECA; powering skills and progress
ECA South Wales Business Day 2025, a day to remember.
AI for the conservation professional
A level of sophistication previously reserved for science fiction.
Biomass harvested in cycles of less than ten years.
An interview with the new CIAT President
Usman Yaqub BSc (Hons) PCIAT MFPWS.
Cost benefit model report of building safety regime in Wales
Proposed policy option costs for design and construction stage of the new building safety regime in Wales.
Do you receive our free biweekly newsletter?
If not you can sign up to receive it in your mailbox here.

























