What is the best deck bearer to post connection?

[GeoKoro13]

Hi all,

I need some expertise advice for a deck Im trying to build.

The plan is to build 3m x 3.2m with composite decking (450mm joist spacing). Do to height restriction Im going to be using 90 x 45 joist (H3 MGP10) and 90 x 90 (join two joist together) for bearers. The joists will rest on hangers on the bearers.

I’m a little bit confused with the bearer to post connection. I’ve seen a post here (https://www.workshop.bunnings.com.au/t5/Outdoor/bearer-to-post-connection/td-p/34361) for that but not sure it’s going work for me.
So, what would be the best way to connect 90 x 90 bearer to 90 x 90 post? I’ve seen a post cap connector (Simpson Strong Tie) that looks good idea but can’t find something similar here?

[EricL]

Hello @GeoKoro13

Welcome to the Bunnings Workshop community. It's fabulous to have you join us, and thank you for sharing your question about your decking project.

Generally, when the timber being used is that thick a lap joint is applied to securely join them together. However, since one part of your assembly is two 90x45s joined together a lap joint will not work. I suggest thinking about putting the 90x45s on top of the 90x90 and securing them together with a Bracket plate on both sides.

In order to give us a better idea of your deck assembly, can you please tell us the height you are building to? 

Let me call on our experienced members @Adam_W and @ProjectPete for their recommendations.

If you have any other questions we can help with, please let us know.

Eric

[GeoKoro13]

Thanks @EricL!

I follow the AS for decking up to 1m from the ground. The bearer table indicates only 2 joists together.

The height of the structure without the post will be 113 (90mm joist + 23mm). I’ve dug already the area for the decking around 130mm below the door.

Also, how to join the two joist? Using bungle screws or bolt-nut?

George

[EricL]

Hi @GeoKoro13

Thanks for that extra information about your deck. I suggest having a quick look at this discussion - Double bearer connection to timber stumps by @ChrisKappa. In that discussion, you'll see a reference to Residential timber decks TDS. In it are some excellent illustrations on methods of joining bearers to post. 

I tend to over-engineer my projects it's the safety freak in me. I suggest using a nut and bolt assembly with the largest washers you can fit in the assembly. This prevents the head of the bolt and the nut from sinking into the timber. You then double up by using bugle screws along the length of the bearer.

If you need further assistance, please let us know.

Eric