Page 14 - Build 151

Shorts
Flooded houses provide insight
We’re experiencing more floods, and BRANZ is busy studying their effect on a variety of home building materials.
BRANZ RESEARCHERS are ooding small-scale houses to gain valuable insights into the e ects of water damage on building materials.
The Flood It! programme, will help designers and homeowners choose building materials that are more resilient to oodwater, support faster recovery after water damage and minimise insurance costs.
Prompted by the increasing number of oods, four houses built at BRANZ will be ooded to monitor how di erent building materials respond to oods. Sensors are installed behind plasterboard linings to track temperature, humidity and timber moisture content in the wall cavities.
‘Being ooded is devastating, and homes can be uninhabitable for weeks or months,’ says Dr Patricia Shaw, BRANZ Research Team Leader. ‘This research aims to get residents back into their homes faster and reduce the nancial impact from ooding e ects.
One of the test houses.
‘The rst house we ooded and monitored has already yielded useful information. Where ventilation holes were cut into the wall, the insulation and framing was visibly drier than where the lining was left intact. Where there was no ventilation, mould developed behind the skirting boards.
‘One surprising observation was that, after 6 weeks, insulation still held water in the lower part of the wall, more so when there was no ventilation. In the closed walls, the framing was still visibly wet.’
Flood It! will look at how simple changes to existing building practice – such as painting all sides of skirting boards – could provide more protection against water damage.
The four small-scale houses represent the most common house-building styles, with two built on concrete slabs and two on piles.
To ood the houses, the researchers install ood barrier systems to keep water in, rather than out. This creates a pond e ect around the house with ‘ oodwaters’ being retained at nearly half a metre for 24 hours.
Water is then pumped away so approaches to drying wall cavities can be tested. The house is monitored for 6 weeks before the walls are opened to assess the condition behind.
85-year weather forecast
THE UNIVERSITY OF BATH AND EXETER UNIVERSITY in the UK have been awarded a £1 million grant to create a time series of predicted hourly weather from now until the end of the century. The aim is to better understand how building designs interact with di erent weather conditions.
The project will transform the way building scientists and engineers consider how di ering weather conditions a ect the built environment.
It comes as concerns grow about what might happen if the energy grid was disrupted during a cold snap – people could be left in rapidly cooling houses. It is unknown how quickly the homes would reach a critical temperature. Answering this question is a key element of energy security given the UK’s reliance on imported gas and recent geopolitical tensions with Russia.
Looking ahead to 2100
A signi cant part of the project will be to create an hourly time series of predicted weather for the next 85 years until 2100. Some will represent typical weather, others extreme conditions such as heat waves and cold snaps.
Di erent weather characteristics will then be tested on over 1,200 di erent building designs to discover how external temperature, wind and sun cause issues for occupants. These include overdemand on central heating systems and air conditioning.
By applying this 85-year forecast to the di erent building examples, the researchers will be able to understand the implications of a weather event. For example, they could study the e ect of a heat wave on the internal environment of a building and the impact on occupants.
12 — December 2015/January 2016 — Build 151