Over 140,000 steel framed houses were built in the UK with over 500 different types but the most popular are the British Steel and Iron Foundation (BISF) with up to 40,000 built in the UK and the Trusteel type with up to 20,000 of the MkII and 17,000 of the 3M. These steel frame houses are scattered throughout the country with a large number in the south east and many of these in Surrey.
With over 500 different types it is impossible to cover all of those here. This blog will therefore be limited to the two types above being BISF and the Trusteel which appear to be the most prevalent in Surrey.
BISF Type House
The BISF type house is easily recognised by the experienced eye typically with steel cladding at first-floor level and rendering or sometimes brickwork at ground floor level. The roof will originally have been clad with asbestos cement corrugated sheets but often today they have been replaced with roof tiles.
Typical BISF House
Trusteel Type House
In contrast the Trusteel type house is not easily recognised even by the experienced eye as it blends in and looks very much like a traditional constructed property with brick walls tiled roof, etc. The giveaway with the Tresteel is the roof structure which is normally constructed of steel trusses but this can only be identified from an inspection within the loft.
Typical Trusteel House
Buying a Steel Frame House
These types of houses are not particularly loved by lenders and obtaining a mortgage can often be difficult as the lender will require confirmation that the structure is sound. This requires a structural inspection.
Inspection of a Steel Framed House
A structural inspection is normally carried out by an engineer and involves a thorough visual internal and external inspection to assess vulnerable areas of the structure in order to determine the likelihood of corrosion to the concealed steel frame. If there are any signs of weakness to the vulnerable areas exposure of the steel frame will be required.
Exposure is normally carried out by a builder or structural repair specialist and normally consists of removing a number of bricks to the outer leaf of the cavity on a Trusteel style property. On a BISF property this will involve cutting out a small section of the concrete panels. This is normally at ground level and below a window sill to at least two exposed elevations.
Once exposure has been carried out a further inspection can be made by the engineer to assess the condition of the steel frame and whether repairs are required. If no repairs are currently required a further inspection is normally recommended at five or ten year intervals depending on the current condition of the frame. Once the inspection is complete the exposed areas can be made good. The exposure, inspection and making good our normally carried out in one to two days.
Repair of a Steel Frame House
If repairs are required there are specialist contractors available for this work and some offer a fixed-price solution. Repairs normally entail works to the base of the stanchions, which are the most likely to corrode and repair or replacement of the corroded parts and or treatment with rust inhibitors and painting.
Author: Tony Waring is a Chartered Building Engineer (C.Build E MCAB), an Associate of the Royal Institute of Chartered Surveyors (AssocRICS) and a member of the Faculty of Party Wall Surveyors (MFPWS). He has over 30 years of surveying experience and 20 years as an engineer.
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