A brief description of the building system is as follows

 
The tilt-up, pre-fabricated walling and building system consists of a 120mm reinforced cast concrete panel incorporating service connections, including window and door openings. Wall panels are erected on conventional or non-standard foundations, dependent on geotechnical constraints, and are rebated and bolted together at corners and wall intersections to ensure lateral stability. Wall panel bases are fixed internally to concrete floors and foundations. An imprint is applied to all external sides of the wall panels.

Entire wall elevations, sections, gable walls and internal walls are cast complete prior to erection and have 100mm thick cast concrete ties below door openings. An additional 100mm thick non-structural floor finish is applied after wall panels have been fixed. Finished floor levels are a minimum of 150mm above NGL (Natural Ground Level). A 220mm x 500mm reinforced concrete roof support beam spans between gable and internal walls. 152mm x 38mm timber rafters are supported by keyed external wall panels. Foundations and roof structure components and elements are in accordance with the relevant sections of SABS 0400: 1990.

A pre-requisite is placed that all materials used in the manufacturing of the tilt-up /pre-fabricated walling and building system are to comply with the latest relevant SABS codes and standards. In particular the main constituent materials of the wall panel are to fully comply with SABS 0100-1: 1992, SABS 0100-2: 1992, SABS 0144: 1995, SABS 0160: 1989, SABS 0161: 1980, SABS 0163-1: 1994, SABS 0163-2: 1994.

Wall panels are cast on either individual completed building foundations / floors, or in an on-site factory environment, dependent on financial viability. Reinforcing, services, lifting, support anchors and corner connection points, window and door openings are all fixed on a horizontal surface and concrete is cast into the reinforcement matrix between perimeter edge shuttering to a thickness of 120mm. Cover to reinforcing is 25mm.

Completed sidewall panels that have been cast face-up, stacked and cured to a minimum of 15 MPa are lifted to a vertical position, transported and placed in position and braced temporarily.

Gable walls are lifted, placed in position and held vertically while corner connection points are bolted and fixed. Internal support walls are lifted and fixed prior to lifting and fixing of the gable and roof rafter support beam. External walls are fixed internally at floor level ensuring the structural integrity of the building structure. The roof rafters are then installed and the building process continues until completion of all services and finishes have occurred. No particular additional maintenance requirements are set, other than normal periodic maintenance that is required and applicable to conventional housing.

Properties regarding Acoustic Performance, Condensation, Durability, Fire Rating, Structural Strength and Stability, Thermal Performance and Water Penetration are addressed in the Agrèment Application Report.

Advantages of this building system are

 
Materials used are durable and strong. (120mm cast 30 MPa reinforced concrete with 485 MPa weld mesh reinforcement vs 140mm bedded concrete masonry 7 MPa bricks / blocks and Class 2 mortar).Both the manufacturing process and the materials used in this system allow for ease of quality control compared to conventional brick or hollow block type construction which is dependent on semi-skilled artisans, unskilled labour and environmental constraints.Incorporation of services within wall panels saves time and enhances quality. (Water, electrical and plumbing service pipes and connections are cast into wall panels that enables modular type quick fit electrical and plumbing installations).

The short duration of the construction and erecting process implies the completion of more housing units in a shorter time period. (Fewer man-hours are required to construct and erect this walling system compared to conventional bricklaying wall construction). />Architectural and aesthetic variations of cast wall panels imprinted with patterns, produce visually pleasing facades. Structural strength of 120mm cast reinforced concrete connected wall panel elements is superior to conventional 140mm bedded concrete masonry block type wall construction. (Ultimate moment, shear, tensile, compression and torsion capacities of this walling system are much higher and can be accurately predicted using the SABS 0100: 1992 code of practice. The relative weakness and high variability factor for bedded masonry block type wall construction has been established). The system is designed to ensure relatively low maintenance costs. (Typical design life cycles for reinforced concrete structures are in excess of 25 years).

The strength of the system is enhanced by the rigidity of the component structural elements and completed structure. (Stress / strain properties of cast concrete wall panels are higher. Modulus of elasticity for 30 MPa cast concrete is 28 GPa vs 8 GPa for bedded concrete block masonry).