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How to build a low-level deck?

IronStan001
Having an Impact

How to build a low-level deck?

I have an alfresco area which I'd like to deck.  The joists (Green lines) will most probably fix straight into the concrete and ideally, I'd like to go 1500mm beyond the concrete (Red line).  I have a storm water pipe (White line) about 800mm out from the concrete.  800mm out from the concrete, the ground is at its lowest point, which is about 200mm lower than the alfresco.  With regards to the footings and bearers, what are my options?

 

Community manager's note: Check out How to build a low-level deck for expert advice.

 

PXL_20230917_054034077~3.jpg

EricL
Bunnings Team Member
Bunnings Team Member

Re: Deck options

Hi @IronStan001 

 

As long as the larger brackets mounting holes are still within the center mass of the timber it should be alright. But if it looks like the mounting holes are too close to the edge then I suggest using the next size down. 

 

I don't know if you are getting affected by the heavy rains we've been having, but I suggest having a sheet of builder's plastic ready to cover your freshly filled footings. In this manner it will not fill up with water and delay the setting of the concrete.

 

If you need further assistance, please let us know.

 

Eric

   

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Re: Deck options

I'll swing by my local store and measure the holes of the 130mm bracket.  For a 100mm bracket, the center of the holes is like:

2024-01-19_15-53-01.jpg

 

I'd have to see on a 130mm bracket how higher up the bottom hole will sit, then I'll make the call from there.

And no, we've taken some rain, but I'm in Victoria and it hasn't been has heavy as some parts of the state/country.

Re: Deck options

I just want to say, I appreciate the comments, feedback and suggestions.  I might be over-thinking and/or over-engineering this, but I take pride in what I'm doing so for my benefit, I want to do it right the first time.  Being able to bounce ideas through here helps.  Googling for answers might be OK sometimes, but when I'm looking for a specific answer...this is where these forums shine.

 

Many thanks for your help, support and advice. 👍

Re: Deck options

It's our pleasure to assist @IronStan001! We'd much rather you over-engineer and end up with a solid deck than wing it and end up with a squishy one. There's nothing worse than a spongey and bouncy deck. 

 

You're doing a great job!

 

Mitchell

 

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Re: Deck options

For a footing that's 300x300x450, how many bags of concrete would I need?  I won't be using quick set, since I need the time.  It's likely that I'll need to do a couple of separate mixes and pours for one of the footings, hence why quickset wouldn't be ideal.

Re: Deck options

Hi @IronStan001,

 

You'll need around four 20kg concrete bags per footer.

 

Mitchell

 

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Re: Deck options

Regarding using chemical anchors, I'm putting 3 x 12mm galvanised threaded rod into a 110 deep (minimum) hole.  Is there a big difference between Chemset 101 vs UltraFix?

 

Using 101, I'd need a new gun, where as UltraFix I don't...and I only need it for 3 holes.

EricL
Bunnings Team Member
Bunnings Team Member

Re: Deck options

Hello @IronStan001 

 

Those two products Chemset101 and Ultrafix are very similar to each other. Chemset101 is made of marine grade resin and can be used in flooded conditions. It also has a larger quantity in the bottle. 

 

However, Ultrafix is a multipurpose product making it ideal to use for your project. It's also more convenient to use as you won't need a specialist gun to inject the adhesive into the holes. Between the two, I would suggest using Ultrafix for ease of use.

 

If you need further assistance, please let us know.

 

Eric

 

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Re: Deck options

When I put the joists in, what would be the better method of sizing them?  Would I measure and cut the joists based on my plans, and hope the measurements are OK and the 140x19 boards fit nicely?  Or, would I leave the joists uncut, lay the boards, then trim the joists to size and fix the last row of noggins?

 

2024-01-30_12-59-33.jpg

 

Re: Deck options

I would cut the joists to size and frame in the end of them with one long length of joist timber @IronStan001. Screw through this framing timber into the ends of the joists. That's a bit easier to do than cutting individual noggins and gives a neater appearance. You can then screw a decking board over the top.

 

If you're not confident in your ability to measure and cut all the joists to the same length, then cutting them after the decking boards have been installed is an option.

 

Mitchell

 

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