Residential gutters - NSW Office of Fair Trading

Residential gutters  

Important Information supplied courtesy of the NSW Office of Fair Trading: 

The following information is a quick reference guide for NSW building professionals and consumers relating to the installation of high fronted gutters in residential homes. 

It does not replace the need to ensure that gutter installation meets the performance requirements of the Building Code of Australia (BCA).

Recent trends

High fronted gutters are popular among consumers as they hide the lower edge of tiles or roof cladding. If a gutter, including high fronted gutters, overflows, it can result in water flowing back into the roof or building. If this occurs over a prolonged period it can permanently damage the internal structure and must be avoided.

Installation requirements

In NSW, all stormwater and drainage works must, by law, comply with the NSW Code of Practice for Plumbing and Drainage. The code requires that all guttering  be designed and installed in accordance with Australian/New Zealand Standard (AS) 3500.3 sections 3, 4 and part 5. Compliance with this standard will meet the relevant requirements of the BCA. Manufacturer’s installation instructions are only a guide and do not overrule the need for the installation to comply with with AS 3500.3.  

Where the installation is the replacement of an existing guttering system, care needs to be taken to ensure the new system complies with current Australian Standards and the BCA.  

Prevention measures

Where a gutter overflow can cause water to flow back into a building, including into the eaves, sufficient overflow measures must be included in the design and installation of the guttering system. The installer is responsible for ensuring the gutter system has sufficient drainage, downpipes and adequate overflow measures for the expected rainfall in the area.  

The following are examples of continuous and non-continuous overflow measures that may be used in combination with each other to meet the relevant requirements.  

Continuous overflow measures    

Non-continuous overflow measures

Other non-continuous measures include the use of rainwater heads with slots or weirs.   

Slotted gutters may also provide an overflow measure, however the slots must be of sufficient size. It is recommended that the gutter manufacturer be consulted on this.  

It is important to note that gutters may become blocked anywhere along their length, so non-continuous overflow measures may not be sufficient to prevent water flowing back into a building.