Research Objective: Quantification of the Interaction between New Zealand Climate and Construction Materials and Systems

Intent: to provide guidance for cost-effective selection of building materials and systems appropriate to specific New Zealand regional climatic conditions, including allowing more informed selection of materials in anticipation of possible changes in climatic conditions.

Projects

Project: New Weathertightness Protection Systems, Drainage Planes, New/Novel Flashing Methods

The drainage effectiveness of drainage plane cladding systems and the extent to which retained water redistributes into framing will be measured. This will enable understanding of the interactions between weathertightness and durability, and determine which are critical issues in achieving both weathertightness and adequate maintenance regimes.

Project: Driving-rain Weather Data for New Zealand

The coincidence of periods of high wind and rain will be determined for New Zealand's major cities. The UK has had driving rain indices for many years that are based upon the coincidence of wind and rain. This information and corresponding requirements have been included in the UK building regulations. The intent of this project is to produce similar information for New Zealand that can be incorporated into NZBC Clause E2.

Project: Moisture Dispersal by Wicking and Diffusion

Wicking and diffusion within walls are potentially critical processes in the weathertightness performance of claddings. A heat and mass transfer model will be developed that predicts the drying rates of wall structures, particularly at drainage planes. This work will involve collaboration with the Oak Ridge National Laboratory (USA) and the Fraunhofer Institute (Germany) both of whom have experience in such models.

Project: Prediction of Atmospheric Corrosion Rates in New Zealand

A model will be developed that will relate the corrosivity of a particular building site with easily measured physical parameters, such as mean wind speeds and directions, topology, rainfall, relative humidity, and sea salt aerosol droplet size. This has direct relevance in predicting the likely durability of metallic components in the built environment, and hence the degree of protection required.

Other projects aiming to quantify the effects of New Zealand climate on construction materials and systems include:

• moisture sensitivity of materials in wall cavities
• in-situ durability evaluation of concrete structures
• reactive powder concrete technology
• quantifying metal fastener corrosion in preservative-treated timber
• development of weathering indices for polymers in New Zealand
• life-cycle costs of buildings
• air-pressure distributions across construction cavities
• cavity ventilation
• encapsulating weathertightness field experience
• joint and flashing weathertightness performance
• drained glazing rebates and durability testing.