I need to shutter a concrete ring for a pond. The ring will be around 300mm wide and between 200mm~250mm high. The ring when shuttered will be above ground and then the surrounding area will be bought up to level with soil backfill. I have some 18mm ply for the job but was hoping to avoid kerfing the back of the ply to bend the radius on the ends of the ring. It is a rectangle with two curved ends. I wondered if 10mm soffit board, hollow or solid might be suitable to use for the curved sections if it is staked often enough. I am using pallet wood for the stakes. Thanks for any advice or insights
i would use soffit as you've suggested but I would use rips of 9mm ply up against the back of it with stakes to support the plastic along its full length/circumference.