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  Good Repair Guide: External Gutters


Roof gutters are an important component of the building envelope, designed to control the disposal of rainwater from he roof. If they are in good working order, gutters should collect the run-off from roof surfaces and direct the water into downpipes and a storm water soakage or reticulation system.

The most important functions of gutters are to help protect against:
 - excessive or concentrated wetting of external wall surfaces
 - water getting inside the building roof space or wall framing
 - increased wetness of soils around the building and subsequent increased moisture loads on basement waterproofing 
 - undermining of areas around the building where there is controlled spillage onto the ground.

Leaking or overflowing gutters may cause problems with dampness in subfloor areas or basements or elevated moisture levels in cladding and within wall framing.

Damp subfloor and basement areas can lead to building problems such as rot and moulds, which could be costly to repair options for dealing with too much subfloor moisture are given n BRANZ Good Repair Guide Damp Subfloors.

This Good Repair Guide covers the repair or replacement of fully accessible metal and plastic external gutters around the outside perimeter of the building that are fixed to a fascia board or rafter ends. It does not cover gutters that are concealed behind a proprietary metal fascia, or internal or within-roof gutters.