Overview
The Gregory Industrialised house is a precast concrete cross-wall house from the 1960s, built in response to the urgent need for rapid, cost-effective housing at a time when system building was being used to address housing shortages and modernise construction. It is also known as the Drury, Drury System 3, Gregory and Gregory Crosswall.
The houses were manufactured by Gregory Housing Ltd and Concrete Ltd, sponsored by Gee Walker & Slater, and designed by J Glover. Approximately 600 were built, mainly in suburban areas as affordable family housing, as two-storey semi-detached or terraced houses. Efficiency, durability and cost-effectiveness shaped the design.
Typical characteristics & construction
The house stands on concrete strip footings and a concrete raft foundation, deepened below the cross walls to form downstand beams, with a damp-proof course (DPC). The front and rear walls are storey-height, dwelling-width timber frame panels, clad with horizontal timber boarding up to ground floor window sill level, tile hanging on timber battens between the ground floor window heads and the upper storey window sills, and timber boarding between the upper storey windows. Polystyrene insulation sits between the frame studs. 3½-inch precast reinforced concrete (PRC) spandrel panels are bolted to the PC cross walls, and E-section PRC capping units finish the gable corners and separating walls.
The gable walls are brick, with a 2-inch cavity and ¾-inch polystyrene insulation, backed by storey-height, room-sized 4-inch PC panels levelled on cast-in bolts. The separating walls are storey-height 7-inch PC panels. Partitions are 2½-inch Gypliner and storey-height 4-inch intermediate PC cross walls.
The ground floor is concrete. The first floor is 5½-inch hollow PC slabs supported on the PC cross walls. Ceilings are plasterboard, and the roof is timber trusses and purlins on seats cast into the cross walls, covered with concrete tiles. In some houses the front and rear timber frame panels are clad with asbestos cement sheets rather than timber boarding, and the gable walls may be storey-height, room-sized exposed aggregate PC panels tied to inner concrete panels.
| Element | Typical construction | Inspection focus |
|---|---|---|
| Substructure | Concrete strip footings; concrete raft with downstand beams below cross walls; DPC | Settlement, cracking, movement, rising damp |
| Front and rear walls | Timber frame panels with timber boarding or asbestos cement sheets and tile hanging; polystyrene insulation; PRC spandrel panels | Deterioration or damage to cladding; asbestos cement condition |
| Capping units | E-section PRC capping units at gable corners and separating walls | Spalling, cracking, outward movement at top and base |
| Gable walls | Brick, cavity, polystyrene, 4-inch PC panels; or exposed aggregate PC panels | Condition of brickwork and panels |
| Separating wall and partitions | 7-inch PC panels; Gypliner and 4-inch PC cross walls | Damage, cracking, structural issues |
| Floors | Concrete ground floor; 5½-inch hollow PC slabs on cross walls | Cracking, movement, damp |
| Ceilings and roof | Plasterboard; timber trusses and purlins on cast-in seats, concrete tiles | Sagging, cracking, water damage; damaged tiles and timbers |
| Windows and doors | Not specified | Frames, seals, glazing, rot |
Potential hazards & inspection priorities
Primary concern: the E-section capping units
The E-section PRC capping units at the gable corners and separating walls are critical to the stability of those parts of the house. Spalling and cracking of these units are common, and they lead to outward movement at the top and base of the units, compromising structural integrity. The units should be inspected closely for all three. Where spalling or cracking is found, a structural engineer should assess the extent of the damage and recommend repair or replacement.
Secondary concern: asbestos cement cladding
Where the front and rear walls are clad with asbestos cement sheets, those sheets are the main asbestos risk. Disturbed asbestos releases fibres that, when inhaled, cause serious respiratory conditions. A thorough asbestos survey should identify any asbestos-containing materials, and any present should be managed through encapsulation, removal or regular monitoring, with all work carried out by qualified asbestos professionals.
Long-term considerations: damp and insulation
The raft foundation and DPC are designed to keep moisture out, but they deteriorate or become compromised over time, and damp leads to structural damage and health concerns. The DPC should be checked for rising damp and water penetration, with moisture readings taken from walls, floors and ceilings. Additional moisture barriers or ventilation improve control where needed.
The original polystyrene insulation does not meet modern energy efficiency standards. Upgrading it improves thermal performance and comfort and reduces energy use, but retrofitting needs careful consideration of the existing structure and should be carried out by qualified professionals so that the structure is not compromised.
Is this house right for you?
The Gregory Industrialised house reflects the drive for rapid, cost-effective construction and has distinctive architectural and structural features. It also brings specific risks that need careful consideration, and a proactive maintenance plan keeps those risks in check.
- Commission a full building survey
- Establish the condition of the E-section capping units before anything else
- Commission an asbestos survey, particularly where asbestos cement cladding is present
- Allow for damp control and insulation upgrades
Regular inspection, asbestos management, insulation upgrades and effective damp control are what keep these houses safe and durable.
Mortgage & resale considerations
The Gregory Industrialised house is not designated defective under the Housing Defects Act 1984. It was designed and built to the standards of its time, so what matters is whether defects or hazards have emerged since. Regular inspection by qualified surveyors identifies them.
What a survey can — and cannot — tell you
A building survey provides an informed assessment of the visible condition and construction of a Gregory Industrialised house. Inspections are non-intrusive and limited to areas that are accessible at the time of inspection.
- Identify visible spalling, cracking and outward movement of the E-section capping units
- Comment on cladding, tile hanging, brickwork and suspected asbestos cement sheets
- Assess signs of dampness and moisture ingress, using moisture meters
- Review floors, partitions, ceilings, windows, doors and the roof
- Highlight defects that may require repair, monitoring, or further investigation
However, there are limitations to what a survey can determine without intrusive investigation.
- Confirm the condition of reinforcement and fixings within the PRC and PC units
- Assess insulation concealed within the wall panels and gable cavity
- Confirm whether materials contain asbestos without specialist sampling
- Inspect areas that are inaccessible or covered at the time of inspection
Where higher-risk indicators are identified, further specialist or intrusive investigation may be recommended.
