Frequently Asked Questions BISF Houses.
We frequently see BISF-related questions being asked on various forums and websites across the internet.
Many of the answers provided albeit with good intent are often completely wrong and misleading even to the point of being dangerous. Many answers are posted by people with absolutely no experience or understanding in this type of property.
What is worse is that new or prospective buyers can often be put off from buying a BISF house, which does in fact represent a sound and excellent investment providing you know what to look for.
All too frequently, common clichés are adopted as soon as the word Prefab is raised, leading many readers to wrongly assume that BISF houses are no different to the temporary prefabricated bungalows built shortly after the war.
Below we shall list some of the most frequently asked questions about BISF houses and provide you with an accurate reply.
Please feel free to add your own questions below in the comments for inclusion onto the main page.
Q: Why are so many BISF Houses still standing if they were only meant as temporary housing?
A: BISF houses were designed and built as PERMANENT housing.
During the Post-War period, many temporary prefabricated properties were constructed under the guidance of the Temporary Housing act 1944. A Tarran Bungalow is just one example of a temporary prefab, that was designed with a limited lifespan.
Q: I hear that it is difficult to get a Mortgage for a BISF house. Is this true?
A: There are many companies that offer Mortgages for BISF properties.
The process of applying for a mortgage is generally no more difficult than applying for a mortgage on any other property. However, a full structural survey using a surveyor who is familiar with the construction type is always advised. Try to avoid using unscrupulous lenders, who often charge far higher rates of interest when lending against any property of Non-Traditional construction.
Q: Are BISF Houses classed as defective under the housing act?
The defective housing act does not apply to British Iron & Steel Federation (BISF) houses.
Primarily, the act applies to a limited number of Precast Reinforced Concrete (PRC) properties.
Q: I have read on the internet that the steel frames of BISF houses can rot through rust, and even collapse. Is this true?
A: No this is False.
Providing that a BISF property has been well maintained, the risk of severe corrosion to the frame is low.
Extensive corrosion has been found at the base of the building’s steel support stanchions, particularly where moisture is found to pool at the stanchion base. Poor maintenance and water ingress are the primary causes. However, if found, the affected portion of the stanchion base can be cut away and replaced at a relatively low cost. (A section of the exterior render would also need to be removed to allow access to the corroded stanchion, or more typically, the stanchion base.)
It should be noted that there are no currently known cases of a BISF property collapsing, due to corrosion or fatigue.
This rumour was established due to the discovery of severe corrosion that was found in the steel frame of an altogether different Precast concrete built property known as an Airey House.
The Airey house was built using a completely different method of construction. Airey Houses incorporated a form of construction that uses steel rods embedded inside a concrete framework. Over time, the chemical composition of the concrete changed, causing it to weaken and corrode the inner steel. The decomposition of the concrete was termed Concrete Cancer.
Concrete cancer occurs when the steel reinforcing within a concrete slab begins to rust. As the steel rusts it expands, displacing the surrounding concrete, causing it to become brittle and crack, thus accelerating the process. Signs of concrete cancer can include crazing and cracking of the concrete (concrete spalling)
Moisture absorption was found to accelerate the process of steel corrosion inside the concrete.
AS A RESULT, THE AIREY HOUSE WAS CLASSIFIED AS STRUCTURALLY DEFECTIVE UNDER HOUSING ACT LEGISLATION.
An unrepaired PRC home is not likely to be mortgageable through standard lending sources.
BISF houses do not suffer from the condition known as Concrete Cancer.
A 1986 BRE report states “The majority of BISF houses are structurally sound”. It went on to point out that if any substantial corrosion of the supporting structure was found, it could be easily removed and replaced with a new section of steel. The report found no significant steel frame problems in the properties that it surveyed, however, it should be noted that stanchion corrosion can be present in properties sited in exposed locations or with poor maintenance schedules.
Q: I hear that BISF houses suffer from lots of issues. Is this right?
A: BISF houses do have certain inherent issues, as do traditional brick properties.
The BRE identified a number of issues with certain BISF houses. The main issues found are listed below.
- Cracking of the render, which can be caused by exterior impact damage, and minor structural movement has occurred in some properties. This can result in corrosion to the metal lath which supports the cement render, causing an increased risk of severe degradation or failure of the render surface.
- Damaged render has no effect on the property’s structural integrity, as the render and supporting steel lath are non-load-bearing.
- Rusting of the steel profile cladding to the upper storey has occurred on a number of properties. It is caused by the failure of the water strips on the gable ends. In rare but severe cases, this has led to rusting of the sheeting rail which supports the cladding panels.
- Over the years, the asbestos cement roof sheeting can deteriorate, and the material can become brittle and cracked. This type of asbestos cement roofing profile is no longer manufactured. The only option is to re-cover the roof with a lightweight modern alternative, such as light steel or composite tile roofing systems.
- Some mild corrosion was found on a number of the stanchions surveyed, particularly those located at the corner of the building. However, during the study, no significant corrosion was found that required immediate remedial work.
Other minor considerations include poor thermal insulation material, discolouration of the steel sheeting when not maintained, and rusting to the steel chimney cowls when present.