This morning, we sat down and did some analysis on the rain collection quantity for each of our roof sections, which totals (including the proposed Conservatory) to 360 square metres. This includes the Skylight region as well. This means that for every 1mm of rain falling on our house roof, we would be collecting 360 litres of water. So for a 10mm rain shower, there would be 3600 litres of water (3.6 tons of the stuff!) pouring into our pipes and down into the rain soak-away modules (or into our rain storage tank when we have made the filtration unit!!).
The eight down pipe connected to the guttering will handle this quantity of water and our analysis and calculations have assigned which section of roof is combined together for each given Downpipe channel. The other calculation was the angle of the guttering slope or fall. For the longest runs, there will be a 30mm drop from one end to the other (about 10 metres of gettering, making it about 3mm drop for every 1metre or in standardised units, about 1 in 300 angle).
We then went around all the eight downpipe channel positions to measure the offset of each module again against the Fascia’s bottom edge so we know how much to add these “drops” in relations of that edge, at the start of a run.
This now means that we have numbers assigned for all the corners of the roof and the next job is to snap a chalk line at the appropriate height and then cut a slot into the Fascia board, ready to receive the Oak guttering pieces.
