25291 Explain Roof Membrane Installation, Re-Roofing Considerations, and Potential Problems

Explanatory notes

1Legislation relevant to this unit standard includes but is not limited to – Health and Safety in Employment Act 1992, Building Act 2004.

2The following applicable document is available for download on the Department of Building and Housing website:

Building Code compliance document Clause E2, containing Acceptable Solution E2/AS1 for External Moisture.

3The New Zealand Building Code (NZBC) is a schedule to the Building Regulations 1992. It provides requirements for compliance with the Building Act 2004 when constructing a new building or altering an existing one. The Building Code sets out performance standards that building work must meet and covers aspects such as structural stability, fire safety, access, moisture control, durability, and services and facilities.

4Definitions

Industry use – common use in the roofing industry.

Job specifications – refer to the documented information found in construction drawings, project specification documents, legislation, regulations and codes.

Manufacturer recommendations – refer to product information and product data sheets provided by the manufacturer of any given product.

Outcomes and evidence requirements

Outcome 1

Explain how temperature and humidity may affect roof bonding adhesives.

Evidence requirements

1.1The potential effects of temperature and humidity on uncured adhesive is explained in terms of solvent evaporation.

1.2The potential effects of temperature and humidity on uncured adhesive is explained in terms of solvent entrapment.

Outcome 2

Explain a ballast roof installation.

Evidence requirements

2.1The principles of a ballast roof and installation are explained in accordance with manufacturer recommendations.

Rangejoins, manufacturing, bonding.

Outcome 3

Explain the use of bond breaker release tape and detail tape on roof membrane.

Evidence requirements

3.1The purpose and use of bond breaker release tape is explained in accordance with the NZBC Acceptable Solution E2/AS1.

3.2The purpose and use of detail tape is explained in terms of industry use and manufacturer recommendations.

Outcome 4

Explain lap bonding requirements and causes of failure.

Evidence requirements

4.1Lap bonding requirements are explained in accordance with NZBC Acceptable Solution E2/AS1.

4.2Causes of failure are explained in terms of incorrect practical application and material use.

Outcome 5

Explain detail for mounting and fastening plant to roof membrane.

Evidence requirements

5.1Detail of mounting structure, membrane coverage and fastening placement are explained in accordance with manufacturer recommendations.

Outcome 6

Explain the considerations for restoration of faulty roof membrane.

Rangefaults may include – poor installation or deterioration;

restoration includes – localised repair, total replacement.

Evidence requirements

6.1Roof inspection activities are explained in terms of determining existing condition and potential hazards prior to repair or replacement.

6.2Importance of work planning sequence is explained in terms of minimising impact to occupants and potential risks of exposure damage to building.

6.3Considerations for determining the extent of membrane repairs or replacement are explained in accordance with industry use.

6.4Solutions for membrane repairs or replacement are proposed in accordance with manufacturer recommendations and the NZBC.

This unit standard is expiring. Assessment against the standard must take place by the last date for assessment set out below.

Status information and last date for assessment for superseded versions

This CMR can be accessed at

Please note

Providers must be granted consent to assess against standards (accredited) by NZQA, before they can report credits from assessment against unit standards or deliver courses of study leading to that assessment.

Industry Training Organisations must be granted consent to assess against standards by NZQA before they can register credits from assessment against unit standards.

Providers and Industry Training Organisations, which have been granted consent and which are assessing against unit standards must engage with the moderation system that applies to those standards.

Requirements for consent to assess and an outline of the moderation system that applies to this standard are outlined in the Consent and Moderation Requirements (CMR). The CMR also includes useful information about special requirements for organisations wishing to develop education and training programmes, such as minimum qualifications for tutors and assessors, and special resource requirements.