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Hot Topic Highlight – BISF Housing

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What is this week's blog about?


In this week’s blog, we take a look at non-traditional steel-framed housing, built by the British Iron & Steel Federation (BISF) between 1945-1948.


This is essential reading for all Residential pathway RICS APC and AssocRICS candidates, as well as any Building Surveying candidates reporting on residential property.


What is BISF housing?


Following World War II, there was a national shortage of housing. To meet high demand and increase the limited supply of housing, new construction methods were adopted, primarily by local authorities and public bodies. These were rolled out as part of the Ministry of Works Emergency Factor-Made Housing Programme.


These new methods were typically non-traditional (i.e., not traditional brick/block cavity or solid walls) and efficient because they:

  • Used minimal imported materials

  • Did not require heavy plant for construction

  • Used unskilled labour on site, as labour (skilled or not) had been depleted by the war

  • Created cost efficiencies


One of these non-traditional methods of construction was introduced by BISF, in the form of steel-framed houses. There are also other forms of steel-framed housing that were not constructed by BSIF.


Around 35,000 BISF dwellings were constructed, of which around 97% were semi-detached and 3% were terraced.


You can read about other forms of non-traditional housing in our previous blog article.


BISF houses were constructed of rolled steel sections with metal roof trusses (see Figure 1) and corrugated metal sheet or asbestos cement roof coverings (over fibreboard insulation sheets). The external walls were typically clad in profile metal sheeting to the upper floors. Rendering or brick were usually found to the ground floor external elevations. See Figure 1 for more on the construction detailing of a BSIF house.


Figure 1 – BISF Construction Detailing

A diagram of a BISF house
NSH (2023) –

What does a BISF house look like?

Thanks go to Philip Santo FRICS, Callum Skene, Adam Roberts and Kerry Landford for the following gallery of BISF photos. 

Are BSIF houses designated defective?




BSIF housing, unlike other forms of non-traditional housing, are not designated as defective under the Housing Act 1985.


However, this does not mean that they are free from defects!


Typically, BSIF houses may suffer from defects such as:

  • Potential corrosion of the steel frame, particularly where properties are in exposed locations with driving wind and rain

  • Cracking to rendered finishes

  • Poor thermal performance

  • Risk of asbestos containing materials (which could be in poor condition)

  • Increase fire risk (see this link)


Are BSIF houses mortgageable?


BSIF houses are not acceptable to all lenders due to their non-standard construction. This may limit mortgagability compared to a traditional masonry cavity walled dwelling.


Other relevant issues to consider include:

  • BSIF houses are often more expensive to insure

  • Repairs to BSIF houses should be undertaken by a contractor who is familiar with the construction type

  • Asbestos roofing materials need to be kept in good condition and repairs or replacement dealt with appropriately given the risk of harm to health


What do surveyors need to be aware of?


BSIF housing can be identified by noting:

  • Render and metal sheet cladding used to the external elevations

  • Semi-detached configuration, although a small number of BSIF terraces were constructed

  • If original, small-sized metal Crittal Hope windows

  • External canopy with metal supporting posts, rather than a porch (although this could be a more recent addition to the dwelling)

  • Corrugated metal or asbestos cement roof

  • Metal trusses in the roof space


Surveyors need to be familiar with the types of properties they may encounter within their local area, together with the associated defects they may find within the local housing stock.


Surveyors carrying out mortgage valuations also need to be familiar with their individual lender client’s guidance, as this will confirm whether a specific housing type is considered mortgageable or not.


For example, Leeds Building Society’s Mortgage Lending Criteria & Guidance confirms the following:

‘Non-Standard Construction: the valuer’s guidance notes include a full list of acceptable construction types. Steel framed properties are not normally acceptable. However, these may be considered where the valuer states that re-saleability is not affected and the property is subject to a durable outer leaf (eg brick, block or stone). In addition, a Structural Engineer’s report would be required in order to confirm that the structural frame is in satisfactory condition and free from corrosion where bolted to the floor slab’.


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Stay tuned for our next blog post to help build a better you.

N.b. Nothing in this article constitutes legal, professional or financial advice.


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