I am building a low level deck 3.6 x 3.2 under my pergola. I intend to use 140x45mm x 3.6 long for my joists. I have to install 8 in total. Can I use 90x90 otter ground screw stirrups with a 45mm packer(such as a 150mm offcut from the 140x45mm) instead of digging 8 holes. The joist are spaced at 450mm centres.
Looking forward to your response.
Welcome to the Bunnings Workshop community. It's sensational to have you join us, and thank you for sharing your question about your decking project.
Using the Otter 690 x 90mm Ground Screw Stirrup is possible, but I would recommend using Builders Edge Pedestal Feet in combination with Pavers instead. When water enters the soil at a vertical angle it loosens the soil and causes it to compress and sink. Compared with water on a horizontal plane where it tends to flow away. If proper draining facilities are placed under the deck very little erosion will occur.
The Builders Edge Pedestal Feet is adjustable and you will not need to use packers to adjust its height. Should shifting occur as the seasons change, you will still be able to adjust the pedestal height under the deck.
The common layout of under-deck draining facilities is made of weed mat, gravel and agi-pipe. A slope is usually placed in the area where the agi-pipe is placed at the very low end. The soil is then compacted using a compacting machine before the weed mat is placed on top then the gravel over it.
Please keep us updated with your progress, we look forward to seeing the start of your decking project.
If you need further assistance, please let us know.