Trusteel MKII Steel Framed House
Trusteel Mk II Also known as: Minox or Trusteel.
Manufacturer: Trusteel Corporation (Universal) Ltd.
Period Built: 1946–66.
Number Built: 20 000. Designer: C.R.Stapleford.
Trusteel Identification Characteristics:
Bungalows, chalet bungalows and 2-storey detached, semi-detached and terraced houses.
Medium pitch hipped or gable roof covered with plain or interlocking concrete tiles.
External walls of brick, plain or harled (pebbledash) render, tile hanging or shiplap boarding throughout or in combination.
Steelwork visible in roof space.
Notes for Surveyors:
Severe corrosion of steel lattice stanchions, particularly at bases.
Severe corrosion of steel lintels and sill supports.
DPC’s near or below ground level.
Debris and mortar droppings in cavity bottom.
Sulfate attack to concrete ground floor slab.
Corrosion of galvanised windows.
History of Trusteel Corporation Ltd
The Trusteel Corporation (Universal) Ltd was first registered in 1945. It was not initially set up as a building company.
The company used to supply steel frames alongside comprehensive design and technical services for customers and clients.
Trusteel provided all drawings necessary for obtaining planning consent and building regulations approval, drawings for site use such as steelwork erection drawings and joinery details. The company also provided site supervisors to oversee the assembly of the steel framing
in relation to the first few houses that were constructed.
The designation MkI or MkII as applied to the lattice frame system has not been seen on any Trusteel literature or drawings. However, many articles describing the system use these terms and the designation has become common usage. MkI may refer only to the prototype design and MkII to later modified frames. For the purpose of this report, MkII is used as a generic term to denote the lattice frame system as distinct from the latter ‘3M’ steel frame which was introduced in 1966.
The Trusteel Corporation are understood to have supplied over 20,000 MkII type properties between 1946 and the mid 1960s to both the public and private sectors.
The typical house structure is based around a framework of steel sections made of thin gauge steel strip lattice components to form columns, floor beams and roof trusses.
The properties are all clad in conventional brickwork and give the appearance of traditionally constructed houses of the post-war period. There are no distinctive external features that can be used to identify them as clearly containing a steel frame.
However, the cavity of the wall is 150mm wide to accommodate the columns and this increased overall wall thickness can offer an indication of the construction.
The internal leaf of the wall is generally made from wood-wool slabs. The steel frame was commonly protected from contact with the brickwork by using a layer of bituminous tape along the outer face of the stanchions.
Property Type – Descriptions.
Due to the construction detailing, there is a risk of cold bridging through the steel frame and condensation forming behind the brickwork, placing the steel frame at an increased risk of corrosion.
Party walls consist of two leaves of lightweight concrete block separated by a cavity.
The internal partitions are usually built of the same.
The ground floor is typically of solid in-situ construction whilst the first floor is built off steel joists which span between the stanchions located in the front and rear external walls.
The pitched roof construction comprises steel lattice roof trusses, sarking felt, battens and concrete tiles.