Starting timber deck question - using Jarrah in coastal area
Hi about to embark on a huge DIY timber deck job and would find any advice helpful. We live in a coastal area. Few questions:
1. Size of footings. The deck is 50m2, posts are 2000 and 1350 apart. I had thought 250x250x300(deep), with the H5 post going through. 2. Advice around using jarrah or pine for the joists & bearers. I know Jarrah is a little harder to work with but is it worth it?
Welcome to the Bunnings Workshop community @joshleah. Many thanks for your question, I'd be happy to assist.
It's fantastic to have you join us and we'd be pleased to assist with your project. Deck footing sizes are dictated by a number of factors. The size of footing is regulated by your local council and is determined by the type of soil in your area, the height of the deck and the load which it will bear. It would be worth reading the post by @trentp about their deck footings as they were quite surprised on the size required.
H4 treated pine would be adequate for your deck posts, but if you can source H5 all the better. For the joists and bearers, H3 treated pine is suitable for above ground use. In regards to using Jarrah, I can't see any significant advantages which would validate the cost to use it.
Please let me know if you need further advice or had questions.