There are many challenges faced when doing knockdown and rebuild projects around Sydney’s Northern Beaches. One common issue we face is how to get the stormwater runoff out of properties that are below street level. There are a number of ways we can work through this within the council’s set of guidelines. One of their most preferred methods is for a new home’s stormwater to be connected into the existing pipelines or run directly to the street. This can commonly be done by way of an easement through a lower neighbour. Sometimes these are already in place on the lands title and other times need to be newly created (which can be quite a process).
One current project of ours in Collaroy is below the street, but had the benefit of a stormwater drainage easement through the neighbouring properties, all the way down to a large council stormwater pipe. Our initial investigations found that there was an existing pipe in place, however, this old pipe was full of tree roots (some of which had grown big enough to fill the 80mm of the 100mm diameter of the pipe!). Council also deemed the sizing of this existing pipe too small to meet current standards, so a newer, larger 150mm pipe would have to be laid. No big deal. New pipes get laid all the time on building sites, right? Well, there was one catch with this job…the council stormwater pipe that we needed to connect to was five houses down the street! This meant that we had to dig a 100 metre long trench through five separate properties in order to install the new 150mm pipe.
After getting over the initial “wow, how are we going to make this happen?”, we set about putting a plan in place to see this huge task completed. This involved:
- Trees in our path
- Providing our client with a detailed cost estimate
- Coordinating approvals, insurances and certification
- Coordinating access with the five neighbours
- Finalising stormwater engineering design
- Undertaking surveys on the five neighbouring yards to ensure the pipe would have the correct fall
- Finding a contractor that shared our approach of ‘it just has to be done’
Interestingly, most contractors that we spoke to just looked at us in amazement and then laughed when we met on site and pointed five houses down the street!!
After three months of prep work and planning, we started digging in the farthest house. The plan was to spend one week in each property to dig, install the pipe and clean up the yard before moving onto the next. We’re happy to say that five weeks after starting, the works were completed! We faced many obstacles along the way that we just had to push through. Here’s just a few:
- Tunnel under brick boundary fences
- Tunnel under an enormous amount of tree roots
- Remove and the replant ENTIRE gardens
- Dig behind garden sheds that were only 400mm away from the fence
- Create the correct falls over the entire length, which at times required the trench to be dug up to 1m in depth
