John is a landlord. He is trying to find out what he needs to do to make sure his rental property meets the healthy homes moisture ingress and drainage standard.

John has a rental property with an enclosed subfloor. He has worked out that his house has an enclosed subfloor because it is built above ground level, has more than two steps leading to both the front and back entrances to the house and at least half of the floor area below the house is closed off by a concrete wall. John’s only way of accessing underneath the house is through an access point.

John reads the Moisture Ingress and Drainage Guidance document(external link) and learns that a polythene ground moisture barrier needs to be installed under the floor. He also learns how to access the area under the house safely so he can install the ground moisture barrier himself. He buys a polythene sheet from the local building retailer that meets the requirements in New Zealand Standard 4246:2016. He then follows the 10-step guide outlined in section 8 of the New Zealand Standard 4246:2016(external link) to install the sheet on the ground under the house.

While John is under the house he checks the underfloor insulation and makes sure it is in reasonable condition, with no mould, dampness or gaps. After successfully installing the ground moisture barrier, he takes some photos of the underfloor area as photographic evidence of compliance. He stores these photos with the receipt for purchase of the ground moisture barrier.

John then checks the drainage and guttering at the property. To prevent flooding or an overflow of water under the house, he checks that the downpipes are not damaged and are flowing to an appropriate outfall. In John’s case, this is the storm water system provided by the council. John also makes sure the gutters and drains are free from leaves and debris. He knows he will need to regularly visit the property to maintain the gutters for tenants.