How to build a low-level deck? What stumps and spans?

[DaveC]

Hey all , hoping to get some advice on placement of posts etc on a low level deck project

Dimensions 2.5 x 10.0

For height reasons can’t run joists and bearers but still want to dig holes concrete the stumps 

frame will need to bearers and joist in one level 

need some info on what timber size , was thinking 140 x 45 for the frame, 

But happy to reconsider based on other recommendations

See attached diagram for layout ,  deck boards will be 2.5 long wondering where the posts should be placed and the spacing required ?

what span between posts and bearers/joists 

thanks in advance for any assistance 

[MitchellMc]

Welcome to the Bunnings Workshop community @DaveC. It's terrific to have you join us, and many thanks for your question about creating a deck.

If you have the available height, then using 140mm of timber will minimise the number of supports you need. I've created a basic layout below for you, with a support spacing of 1500mm. That's not quite the max span of the 140mm, but its were I'm comfortable advises to. You could span the supports less frequently, but you'll need to reference timber span tables and decide where you'd like to set supports. 1500mm is a safe spot, ensuring your deck will not become bouncy or sponge underfoot.

The joists in my render are set at 500mm centres.

Here's a helpful guide on How to build a low-level deck.

Please let me know if you have any questions.

Mitchell
 

[DaveC]

Thanks Mitchell - much appreciated,  whats size holes would you suggest, i normally do 600 depth on everything  but given the post height isnt  that high ( approx 200mm) is 600 still required ?

I ve been searching the net and see others use two 90 x45 effectively making it a 90x90 joist/bearer 

would the same spans apply if i were to do this ?  it would give more clearance  to the ground .

Could you provide a link to the posts/stumps sold from Bunnings -seems to be a few different opinions 

90 x 90 or 100 x 100 - cedar vs pine etc  thoughts? 

thanks again 

[EricL]

Hello @DaveC 

Let me try and answer some of your questions.

• I suggest going with the 600mm depth when it comes to footing. I personally would rather over engineer it rather than compromising on strength.
   
• A solid 90x90 has its internal structure and fibres woven together to create strength. Two 90x45's bolted together will be strong, but not as resilient as a 90x90. The spans would be different. 
   
• Here is a link to H4 posts.

I suggest watching this Bunnings guide on how to build a deck:

• How to plan out your deck 
   
• How to set out a deck
   
• How to install stumps
   
• How to install bearers
   
• How to install joists
   
• How to lay decking
   
• How to add a step to your deck.  

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

Eric

[DaveC]

Hi team - thanks again for your tips 

Was wondering do I use the structural or non-structural  h4 post 

would stirrups also work - rather than post - is there any advantage from one over the other ?

I ve watched the videos previously - very helpful - thanks 

[EricL]

Hello @DaveC 

For ease of use I suggest using H4 posts as you can cut them to the height that you need and then concrete it into place. Stirrups on the other hand require you to have a concrete footing that is already at the correct height. Plus, there is no room for adjustment when compared to an H4 post.

If you need further assistance, please let us know.

Eric

[DaveC]

thanks again - about to buy all the timber - just confirming h4 post - the link i was sent had structural non structural - obviously there is a variance in price, which would you suggest ? - 

[EricL]

Hi @DaveC 

I recommend structural H4 so that it is rated for construction. 

Eric