Marie-Curie IAPP ‘Green Roof Systems’ Project
The Green Roof Research Conference 18-19 March 2013, Sheffield
Moisture transfer from drainage layer to substrate: system development with a water distribution element + a wicking mat Ralf Walker ZinCo GmbH, ralf.walker@zinco-greenroof.com Introduction So far the moisture transfer from drainage (if used as reservoir) took place by using direct capillarity between bulk materials such as e.g. Zincolit on the one hand side and filter sheet/substrate on the other. The filling material Zincolit or any other comparable material have some negative effects: 1. taking volume for storage away, 2. adding to the weight of the green roof, 3. capillary irrigation requires flat (0°) roofs which are not very common or need to be specified at an early stage. A solution was sought and found to avoid these negative effects / to be able to use capillary irrigation also on roofs with slope. After having had the idea it was important to characterise furthermore which kind of components would work together and up to which substrate-depth. Part of the work will be explained here.
Overview of Methodology A test was developed in order to characterise different combinations of Aquatec® / Wicking Mat and substrates. Variations were used for substrate type and depth. The following Figure shows the build-up using the Aquatec® / Wicking Mat-System and different substrate depth and types. Also the distribution of irrigation by driplines in combination with Aquatec® was further examined.
Figure 1: Prepared cylinders on Aquatec® / Wicking Mat-System
Marie-Curie IAPP ‘Green Roof Systems’ Project
The Green Roof Research Conference 18-19 March 2013, Sheffield
Key Findings When looking at the horizon of water uptake within the substrate we can see that the water moves even up in pure Zincolit. The system therefore can achieve even wider applications in future as compared to today where it’s mainly used for lawn type vegetation.
Figure 2: Water horizon taking place by capillary irrigation by the wicking mat.
The water distribution within the Aquatec®-Elements can be easily studied using a fluorescent tracer (Uranin). An application guideline was developed differentiating in roof situations (slope).
Figure 3: Distribution of water running out of driplines within Aquatec®-elements
Further Reading https://sites.google.com/a/sheffield.ac.uk/green-roof-research/