Hi @felipenm,
Thank you for your question about creating a curved formwork for your concrete pour and drainage requirements for your outdoor shower.
You can use a flexible material such as this Saxon 100mm x 10m Black Garden Edge to act as your formwork. The main thing when using a flexible material like this as formwork is to ensure it is well-staked, particularly along the radius edge, to prevent the weight of the concrete from bulging out your form.
I'd suggest grabbing a pack of Growies 50 x 25mm 450mm Hardwood Garden Stakes and spacing them no more than 200mm apart along the radius edge.
While not universally mandated, many councils require outdoor showers to have a drainage solution to prevent pooling, erosion, or water runoff into public spaces. In areas where wastewater could impact the environment or flow onto neighbouring properties, a drain may be required. If the outdoor shower is connected to a hot water system, this can also change the requirements.
It is best to check with your local council to see your obligations when installing an outdoor shower. A suitably licenced plumber who operates in your area should also be able to assist with this question.
Let me know if there is anything else I can assist with.
Jacob
