Panania Granny Flat Project
The Design
Panania project: the Melanie design adapted to a flood-prone, sloping property with a sewer constraint. The project brought together the floor plan, approval requirements, drainage and structural design before construction.
The Melanie two-bedroom design includes a front patio, a large bathroom with laundry and an internal hallway that creates separation between the bedrooms. This project used polyurethane kitchen and bathroom cabinets.
The case study below explains how the site’s three constraints were addressed. Its recorded costs and times describe this particular historical project; they are not current quotations or a promise of the same outcome on another property.
The Issues
Historical site costs: the dollar amounts below are recorded examples from this project, not current rates or a quotation for another property.
This Panania property had a few issues to resolve before construction could commence.
The Panania property had three major issues:
1. The property is situated in a Flood-Zone and
2.The property slopes towards the rear and
3. The Sewer Mains is situated cross the rear of the block.
To resolve these issues, we had to do the following:
1. We had to get an AHD Survey from a Registered Surveyor. We also spoke with Bankstown Council’s Hydraulic Engineer. He informed us of the required finished floor level. This meant raising the floor 900 millimeters above the natural ground level. We raised it on piers and had our structural engineer detail the footings. The DA process was a long one and we had to spend more money for the Surveyor and the Engineer – about $2,000 in total.
2. The drainage issue was resolved by designing a dispersion pit. This meant designing the pit for the approval. We also had to build this pit as part of the construction phase. It cost around $2,500.
3. The Sewer issue was resolved by distancing the granny flat so that it was over 600 mm from the sewer. We couldn’t totally avoid the Sewer’s zone of influence but we designed it to avoid concrete encasement. The Sydney Water Approval cost $1,300 including all inspections. Longer footings were needed which cost around $3,000 during the footing stage. The piers had to be dug an extra 2 metres, which is quite a lot for 50 piers.
Our Persistence
The project received approval through Bankstown Council after the sewer, drainage and flooding issues were addressed. The recorded approval process took two months, and construction took nine weeks. These are the historical times for this project; the process and timing for a new property depend on its requirements.
For your property, compare our granny flat designs and floor plans, explore the separate approval price calculator and build price calculator, or talk to us about your site. Site-specific survey, drainage, structural and sewer work needs assessment and confirmation in your written quote.
See more completed granny flat projects, including the Sutherland project’s drainage, retaining and sewer solutions.