When it comes to purchasing a property in the UK, understanding the intricacies of different house types is crucial. One such property type that often piques the interest of home buyers and investors is the Jansel house. Built predominantly in the 1960s, these properties have unique characteristics and construction methods that set them apart from other homes. This article delves into the essential aspects of Jansel houses, providing a detailed overview of their construction, typical hazards, and inspection tips.

Historical Context and Manufacturing

The Jansel house, a product of the 1960s, was manufactured by H C Janes Ltd, a company known for its innovative approach to system-built properties. During this period, there was a significant demand for quick and cost-effective housing solutions, leading to the development of various system-built homes. The Jansel house was one such solution, designed to meet the housing needs of the time efficiently.

Typical Locations and Numbers Built

Jansel houses are primarily found in suburban areas across the UK, particularly in regions that experienced rapid urban expansion during the 1960s. While the exact number of Jansel houses built is not well-documented, it is estimated that several thousand were constructed to address the post-war housing shortage.

Design and Construction

The design and construction of Jansel houses were spearheaded by H C Janes Ltd, who also served as the primary manufacturer. These properties are typically two-storey semi-detached or terraced houses, featuring a medium pitch gable roof covered with Nuralite roofing or interlocking concrete tiles. The front and rear external walls are made of asbestos cement sheets or brick up to the first-floor level, with tile hanging above. The gable wall is rendered with pebbledash, and the gable apex is constructed from steel sheets.

Identification Characteristics

Identifying a Jansel house involves looking for specific architectural features and construction materials. Here are some key characteristics to help you recognize a Jansel house:

• Two-storey semi-detached or terraced structure: Jansel houses are typically two-storey buildings, either semi-detached or terraced.
• Medium pitch gable roof: The roof has a medium pitch and is covered with either Nuralite roofing or interlocking concrete tiles.
• Asbestos cement sheets or brick walls: The front and rear external walls are made of asbestos cement sheets or brick up to the first-floor level, with tile hanging above.
• Pebbledash gable wall: The gable wall is rendered with pebbledash, a common feature in Jansel houses.
• Steel sheet gable apex: The gable apex is constructed from steel sheets, adding to the unique appearance of these properties.

Typical Construction Details

Understanding the construction details of Jansel houses is essential for identifying potential issues and ensuring proper maintenance. Here is a breakdown of the typical construction elements:

Substructure

• Concrete column bases: The substructure consists of 2′ 6″ square concrete column bases.
• Concrete edge beams: 2″ x 9″ concrete edge beams are used in the construction.
• Concrete slab and DPM: The ground floor is a concrete slab with a damp-proof membrane (DPM) to prevent moisture ingress.

Frame

• PRC columns: The main frame includes 9″ x 4 1/2″ eaves height precast reinforced concrete (PRC) columns.
• RSC lattice beams: 9 1/4″ and 8″ rolled steel channel (RSC) lattice beams with timber inserts at the first floor and eaves level are connected to the PRC columns by brackets bolted to cast-in lugs.

External Walls

• Timber frame panels: The front and rear walls are made of storey-height timber frame panels with intermediate hollow box RS stanchions.
• Asbestos cement sheets and tile hanging: The panels are sheathed externally with plywood and clad with asbestos cement sheets up to the first-floor level, with tile hanging on timber battens above.
• Foil-backed plasterboard lining: The internal lining consists of foil-backed plasterboard, with insulation between the frame studs.
• Pebbledash render: The gable wall is rendered with pebbledash, using 3″ x 12′ x 2′ 10″ PRC panels fixed to PRC columns by RSA angle clips.
• L-shaped PRC corner units: 2 1/2″ x 4′ 1 9/16″ L-shaped PRC corner units are fixed to PRC columns by Abbey clips and joined along the top and bottom edges by recessed steel dowels.

Separating Wall

• PRC panel cavity wall: The separating wall consists of 3″ x 3’2″ and 4’10” x 11’10” PRC panel cavity walls, with the cavity filled with sand.

Partitions

• Timber stud partitions: Internal partitions are made of timber studs lined with plasterboard.

Floors

• Concrete ground floor: The ground floor is constructed from concrete.
• Chipboard first floor: The first floor consists of chipboard on timber joists.

Ceilings

• Plasterboard ceilings: Ceilings are made of plasterboard.

Roof

• Prefabricated timber units: The roof is constructed from prefabricated timber units and covered with Nuralite roofing.

Typical Hazards and Risks

While Jansel houses offer unique architectural features, they also come with certain hazards and risks that potential buyers and investors should be aware of. Here are some common issues associated with Jansel houses:

Asbestos

One of the most significant hazards in Jansel houses is the presence of asbestos cement sheets in the external walls. Asbestos was commonly used in construction during the 1960s due to its fire-resistant properties. However, it is now known to pose serious health risks if disturbed. Asbestos fibres can become airborne and inhaled, leading to respiratory diseases such as asbestosis, lung cancer, and mesothelioma. It is crucial to have a professional asbestos survey conducted before any renovation or demolition work.

Structural Integrity

The use of PRC columns and RSC lattice beams in the construction of Jansel houses can lead to structural issues over time. PRC columns are prone to carbonation, a process where carbon dioxide from the air penetrates the concrete and reacts with the calcium hydroxide, leading to a reduction in the pH level. This can cause the steel reinforcement within the concrete to corrode, compromising the structural integrity of the building. Regular inspections and maintenance are essential to identify and address any signs of deterioration.

Thermal Insulation

Jansel houses were built with insulation between the frame studs, but the level of thermal insulation may not meet modern standards. This can result in higher energy bills and reduced comfort levels. Upgrading the insulation in the walls, roof, and floors can significantly improve the energy efficiency of the property.

Damp and Moisture

The presence of a damp-proof membrane (DPM) in the ground floor construction is intended to prevent moisture ingress. However, over time, the DPM can deteriorate, leading to damp issues. It is essential to check for signs of dampness, such as mould growth, musty odours, and discoloured walls or floors. Addressing damp issues promptly can prevent further damage and maintain a healthy living environment.

Defective Premises Act

The Defective Premises Act 1972 imposes a duty on builders, developers, and landlords to ensure that properties are constructed and maintained to a reasonable standard. While Jansel houses are not specifically listed as defective under the Act, the presence of PRC columns and asbestos cement sheets can raise concerns about their compliance with modern building standards. It is advisable to seek professional advice and conduct thorough inspections to ensure the property meets current safety and quality requirements.

Inspection Tips for Jansel Houses

Inspecting a Jansel house requires a keen eye for detail and an understanding of the unique construction methods used. Here are some tips to help you conduct a thorough inspection:

Exterior Inspection

• Check for asbestos: Look for asbestos cement sheets in the external walls. If you suspect the presence of asbestos, arrange for a professional asbestos survey.
• Examine the roof: Inspect the roof for signs of damage or wear, particularly if it is covered with Nuralite roofing or interlocking concrete tiles. Check for missing or broken tiles and ensure the roof is watertight.
• Assess the gable wall: Examine the pebbledash render on the gable wall for cracks or deterioration. Check the steel sheet gable apex for signs of rust or corrosion.
• Inspect the external walls: Look for any signs of damage or wear in the brick or asbestos cement sheets. Check for cracks, bulging, or loose tiles in the tile hanging above the first-floor level.

Interior Inspection

• Check for dampness: Look for signs of dampness, such as mould growth, musty odours, and discoloured walls or floors. Pay particular attention to the ground floor, as the DPM may have deteriorated over time.
• Examine the insulation: Assess the level of insulation in the walls, roof, and floors. Upgrading the insulation can improve the energy efficiency of the property.
• Inspect the PRC columns: Check for signs of carbonation and corrosion in the PRC columns. Look for cracks, spalling, or rust stains on the concrete surface.
• Assess the structural integrity: Examine the RSC lattice beams and timber inserts for signs of damage or wear. Ensure that the brackets and cast-in lugs are secure and free from corrosion.

Utilities and Services

• Check the plumbing: Inspect the plumbing system for leaks, corrosion, and signs of wear. Ensure that the pipes are in good condition and that there are no blockages or water pressure issues.
• Examine the electrical system: Assess the electrical system for safety and compliance with modern standards. Look for outdated wiring, overloaded circuits, and faulty outlets or switches.
• Inspect the heating system: Check the heating system for efficiency and functionality. Ensure that the boiler, radiators, and thermostats are in good working order.

Typical Defects in Jansel Houses

Jansel houses, like any other property type, are susceptible to certain defects. Here are some common issues to look out for:

Asbestos-Related Issues

As mentioned earlier, the presence of asbestos cement sheets in the external walls poses a significant health risk. It is essential to have a professional asbestos survey conducted and, if necessary, arrange for safe removal and disposal by licensed contractors.

Carbonation and Corrosion

The PRC columns used in Jansel houses are prone to carbonation, leading to corrosion of the steel reinforcement. Regular inspections and maintenance are crucial to identify and address any signs of deterioration. If significant damage is found, it may be necessary to undertake structural repairs or replacements.

Thermal Bridging

The construction methods used in Jansel houses can result in thermal bridging, where heat is transferred through the building envelope, leading to heat loss and reduced energy efficiency. Upgrading the insulation and addressing any gaps or weaknesses in the building envelope can help mitigate this issue.

Damp and Moisture Ingress

Damp and moisture ingress can be a common problem in Jansel houses, particularly if the DPM has deteriorated. Regular inspections and prompt repairs are essential to prevent further damage and maintain a healthy living environment.

Outdated Services

The plumbing, electrical, and heating systems in Jansel houses may be outdated and in need of upgrading. Ensuring that these systems meet modern standards and are in good working order is essential for the safety and comfort of the occupants.

Conclusion

Jansel houses, with their unique construction methods and architectural features, offer a fascinating glimpse into the post-war housing solutions of the 1960s. However, they also come with certain hazards and risks that potential buyers and investors should be aware of. By understanding the typical construction details, identifying common defects, and conducting thorough inspections, you can make informed decisions and ensure the long-term safety and value of your investment.

At Flettons, we’re committed to safeguarding your investment. When considering a property purchase, trust our seasoned expertise to reveal any hidden threats. For a thorough building survey, get your instant quote through our quote calculator or reach out directly at 0203 691 0451. Your home’s safety is our top priority.

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