Historical Context and Background

The Channello house, a distinctive property type in the UK, was manufactured by Channello Construction Co. and designed by the architectural firm Hepworth & Wornum. These houses were primarily built in the 1920s, a period marked by a significant housing shortage post-World War I. The Channello house was part of a broader movement to provide affordable and quickly constructed homes to meet the urgent demand.

These properties are typically found in suburban areas, often in regions that experienced rapid development during the interwar period. The Channello house is a two-storey structure, easily identifiable by its medium pitch gable roof covered with tiles or slates and external walls made of precast (PC) blocks throughout.

Manufacturers and Designers

Channello Construction Co.

Channello Construction Co. was a prominent player in the early 20th-century construction industry, known for its innovative use of precast concrete (PC) blocks. The company aimed to revolutionize house building by introducing methods that reduced construction time and costs while maintaining structural integrity.

Hepworth & Wornum

The architectural firm Hepworth & Wornum played a crucial role in designing the Channello house. Their design philosophy focused on rational and functional housing solutions, which aligned perfectly with the needs of the time. Their work on the Channello house is documented in various historical references, including Bemis A F’s “The Evolving House” and the “Interim Reports of Committee on New Methods of House Construction” from 1924.

Typical Characteristics of the Channello House

Construction Details

Substructure

The Channello house features concrete strip footings, a common foundation method that provides stability and support for the structure. The under-building is constructed with PC blocks, and a damp-proof course (DPC) is included to prevent moisture from rising through the walls.

External Walls

The external walls are made of 2′ x 1′ grooved and flanged PC blocks, creating a cavity wall system. This design includes aggregate flanged clinker PC blocks and channel section clinker precast reinforced concrete (PRC) lintels at the first floor and eaves level. PC slab cavity closers are used to seal the cavities, enhancing the thermal efficiency of the house.

Ground and First Floors

The ground floor consists of 2″ PC slabs, providing a solid and durable base. The first floor is constructed with flanged PC slabs supported by rolled steel joists (RST), ensuring structural stability and load-bearing capacity.

Ceilings and Roof

The ceilings are made of 1 1/2″ clinker PC slabs, offering fire resistance and sound insulation. The roof structure includes RST rafters and flanged clinker PC blocks, covered with slates or tiles, depending on the variant.

Variants

Some Channello houses feature plaster ceiling slabs and a roof covered with tiles instead of slates. These variations were likely introduced to meet different aesthetic preferences and regional building regulations.

Typical Hazards and Risks

Structural Integrity

One of the primary concerns with Channello houses is the potential for structural issues due to the age and materials used. Over time, the PC blocks and PRC lintels can deteriorate, leading to cracks and weakened structural elements. Regular inspections are essential to identify and address these issues promptly.

Moisture Ingress

Despite the inclusion of a DPC, moisture ingress can still be a problem, particularly if the DPC has deteriorated or if there are issues with the external walls. Moisture can lead to dampness, mould growth, and damage to internal finishes.

Corrosion of Reinforcement

The steel reinforcement within the concrete elements can corrode over time, especially if the concrete has been exposed to moisture. This corrosion can compromise the structural integrity of the house, making it crucial to monitor and address any signs of rust or spalling concrete.

Thermal Efficiency

While the cavity wall system provides some thermal insulation, the overall thermal efficiency of Channello houses may not meet modern standards. Upgrading insulation and improving airtightness can help enhance energy efficiency and reduce heating costs.

Defective Premises Act Considerations

The Channello house is not specifically classed as defective under the Defective Premises Act. However, given its age and construction methods, it is essential to conduct thorough inspections to ensure it meets current safety and habitability standards. Any defects identified should be addressed promptly to maintain the property’s value and safety.

Inspection Guide for Surveyors

Pre-Inspection Preparation

Before conducting an inspection, gather as much information as possible about the specific Channello house, including its construction details, previous maintenance records, and any known issues. This preparation will help you focus on critical areas during the inspection.

External Inspection

Roof

• Check the condition of the tiles or slates, looking for any signs of damage or missing pieces.
• Inspect the RST rafters and flanged clinker PC blocks for signs of corrosion or deterioration.
• Ensure the roof is watertight and free from leaks.

Walls

• Examine the PC blocks for cracks, spalling, or other signs of damage.
• Check the condition of the PRC lintels at the first floor and eaves level.
• Look for any signs of moisture ingress or dampness.

Internal Inspection

Ground and First Floors

• Inspect the PC slabs for cracks or other signs of structural issues.
• Check the condition of the RST supporting the first floor.

Ceilings

• Examine the clinker PC slabs for any signs of damage or deterioration.
• Ensure the ceilings are free from moisture stains or mould growth.

Partitions and Separating Walls

• While the specific construction details of partitions and separating walls are not known, inspect these areas for any signs of structural issues or damage.

Moisture and Dampness

• Use a moisture meter to check for dampness in walls, floors, and ceilings.
• Inspect the DPC for any signs of deterioration or failure.

Thermal Efficiency

• Assess the insulation levels in the walls, floors, and roof.
• Check for any drafts or areas of heat loss.

Typical Defects in Channello Houses

Cracking and Spalling

Cracking and spalling of the PC blocks and PRC lintels are common defects in Channello houses. These issues can compromise the structural integrity of the property and should be addressed promptly.

Corrosion of Steel Reinforcement

Corrosion of the steel reinforcement within the concrete elements can lead to structural issues. Regular inspections and maintenance are essential to prevent and address this problem.

Moisture Ingress and Dampness

Moisture ingress and dampness can cause significant damage to the internal finishes and structure of the house. Ensuring the DPC is in good condition and addressing any external wall issues can help mitigate this risk.

Thermal Efficiency Issues

The thermal efficiency of Channello houses may not meet modern standards, leading to higher heating costs and potential discomfort for occupants. Upgrading insulation and improving airtightness can help enhance energy efficiency.

Maintenance and Repair Recommendations

Regular Inspections

Conduct regular inspections to identify and address any issues promptly. Focus on areas prone to structural issues, moisture ingress, and corrosion.

Structural Repairs

Address any cracks, spalling, or other structural issues promptly. This may involve repairing or replacing damaged PC blocks, PRC lintels, or steel reinforcement.

Moisture Control

Ensure the DPC is in good condition and address any issues with the external walls to prevent moisture ingress. Consider installing additional moisture barriers if necessary.

Thermal Upgrades

Upgrade insulation in the walls, floors, and roof to improve thermal efficiency. Seal any drafts and consider installing energy-efficient windows and doors.

Conclusion

The Channello house, with its unique construction and historical significance, offers both opportunities and challenges for home buyers and investors. Understanding the typical characteristics, potential hazards, and maintenance requirements of these properties is essential for making informed decisions.

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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