Unit of competency details

Unit descriptor 

This unit covers the process of constructing low-profile timber or modular retaining walls and defines the standard required to: plan and prepare for construction; mark out the site and assemble materials; construct footings and place reinforcing; carry out wall construction; clear up the site and dispose of waste.

Application of the unit 

This unit applies to the process of constructing low profile timber or modular retaining walls in landscape settings and involves working under routine supervision with intermittent checking. Responsibility for some roles and co-ordination within a team may be required.

Prerequisite units 

Employability skills 

This unit contains employability skills.

ELEMENT 

PERFORMANCE CRITERIA 

1. Plan and prepare work

1.1. Personal Protective Equipment (PPE) and clothing is selected, used and maintained.

1.2. Work instructions relating to constructing the retaining wall are interpreted and confirmed with the supervisor.

1.3. Tools and equipment are prepared and used according to the supervisor's instructions.

1.4. Manual handling and other Occupational Health and Safety (OHS) hazards are identified, risks assessed and reported to the supervisor.

1.5. Services are located according to site and construction

1.6. The quantity and quality of materials are checked to ensure they conform to the requirements of the job plans.

2. Mark out site for retaining wall

2.1. The position of the retaining wall is marked out according to site and construction plans.

2.2. The location and depth of excavations are determined from site and construction plans.

2.3. Profiles are established to conform to the tolerances designated by the supervisor and/or site and construction plans.

2.4. Survey benchmarks are established.

3. Prepare footings according to industry standards

3.1. Foundations for the retaining wall are excavated to depth and dimensions according industry standards.

3.2. Soil and waste material are removed and stockpiled to ensure a safe working area.

3.3. Reinforcing and/or steps in the excavated site are located and positioned according to industry standards.

3.4. Pegs or levels are positioned to maintain even depth and horizontal plane to the top of footings.

3.5. Footings are placed, consolidated and finished to determined levels, to ensure coverage of reinforcement as necessary and according to industry standards.

4. Prepare and install retaining wall components

4.1. Components for installation are prepared and laid out.

4.2. Components to be cut are marked out to length and/or shape and cut accurately to the requirements of profiles already established.

4.3. Drainage media is installed according to supervisor's instructions.

4.4. Base layer of retaining wall is constructed to a point above the top of the drainage media and weep holes are formed where indicated.

4.5. Fill material is back-filled and compacted behind base of retaining wall.

4.6. Retaining wall components are constructed to dimensions, profiles and levels as outlined in the specified site and construction plans and/or according to supervisor's instructions.

4.7. Capping to top of retaining wall is set to specified levels with a tolerance appropriate to the style of capping.

5. Clean up site and store tools and equipment

5.1. Soil and waste material from the site is disposed of or recycled to minimise damage to the environment.

5.2. Unused construction materials are stored and stacked for future re-use according to supervisors instructions.

5.3. All tools and equipment are cleaned and stored according to supervisors instructions.

REQUIRED SKILLS AND KNOWLEDGE 

This section describes the skills and knowledge required for this unit.

Required skills 

• read and interpret site and construction plans
• calculate the amount of materials required and accurately mark out the area to be retained
• sort soil and waste material from the excavation site in an environmentally aware and sensitive manner, such as sorting it into organic, inorganic and recyclable piles
• use literacy skills to follow sequenced written instructions and record information accurately and legibly
• use oral communication skills/language competence to fulfil the job role as specified by the organisation including questioning, active listening, asking for clarification and seeking advice from supervisor
• use numeracy skills to estimate, calculate and record routine workplace measures
• use interpersonal skills to relate to people from a range of social, cultural and ethnic backgrounds and with a range of physical and mental abilities.

Required knowledge 

• different construction materials for retaining walls
• construction approaches and methods
• OHS responsibilities of employees
• safe lifting practices for carrying large and heavy components
• the environmental impact of soil disturbance when excavating an area to be retained and the environmental effects of altering water flow when installing retaining walls, with or without drainage media
• methods of disposing of soil and waste materials in order to minimise damage to the environment
• Building Code of Australia relating to constructing retaining walls.

EVIDENCE GUIDE 

The evidence guide provides advice on assessment and must be read in conjunction with the performance criteria, required skills and knowledge, range statement and the Assessment Guidelines for the Training Package.

Overview of assessment 

Critical aspects for assessment and evidence required to demonstrate competency in this unit 

The evidence required to demonstrate competency in this unit must be relevant to workplace operations and satisfy holistically all of the requirements of the performance criteria and required skills and knowledge and include achievement of the following:

• plan and prepare for construction
• mark out the site and assemble materials
• construct footings and place reinforcing
• carry out wall construction
• clear up the site and dispose of waste.

Context of and specific resources for assessment 

Competency requires the application of work practices under work conditions. Selection and use of resources for some worksites may differ due to the regional or enterprise circumstances.

RANGE STATEMENT 

The range statement relates to the unit of competency as a whole.

Retaining walls may include:

• all types of low [<900mm] retaining walls using timber and modular concrete units.

Unit sector 

Landscape

Co-requisite units 

Competency field