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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?

 

PXL_20230917_054034077~3.jpg

Re: Deck options

I'm leaning towards the Integrain UltraDeck, but not totally sure which will offer the best protection: Oil, Stain or Finish.

 

Reading up on what product is best is making my head spin.

 

Thoughts?

Re: Deck options

@IronStan001,

 

For a new deck go with the Intergrain 4L Natural UltraDeck Timber Decking Oil. For an aged deck (in 24 months), go with the Intergrain 4L Merbau UltraDeck Timber Decking Oil, which has Merbau-coloured pigments in it to restore the colour. For a ten-year-old deck that is completely grey and drained of colour, go for the Intergrain 4L Merbau UltraDeck Timber Decking Stain.

 

They all protect your deck, it's just really the level of pigments in each one.

 

Mitchell

 

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Re: Deck options

Being water based, would that mean more maintenance than if it was oil based?

 

I'm trying to figure out which product will tolerate sun and weather, require minimal cleaning/prep when recoat is needed, and hopefully last at least 12 months between coats.

EricL
Bunnings Team Member
Bunnings Team Member

Re: Deck options

Hello @IronStan001 

 

According to the Intergrain website the Intergrain UltraDeck Timber Oil is a water based, lightly pigmented oil and will offer long lasting protection compared to a traditional oil-based coating whilst enhancing the natural colour and characteristics of your timber.

 

Longevity and service life is of course subject to the weather and environment. Harsh sun, heavy rain and hail can easily damage the finish on your deck. But I agree with MitchellMc on using the water-based one for easy clean up.  

 

If you need further assistance, please let us know.

 

Eric

 

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Re: Deck options

Being a Melbourne resident, we dont have a harsh climate so I'd agree that the UltraDeck should do the job.  I'll use that to start off with and go from there so I'll see how long it lasts.

 

With respect to fixing the boards, I have 304 grade stainless steel screws and I've read 316 should be used within 5km from the coast...which I'm far from.  304 should be fine I assume?  And using 140mm boards, would I do 2 or 3 screws per joist?

EricL
Bunnings Team Member
Bunnings Team Member

Re: Deck options

Hi @IronStan001 

 

Thats sounds like a good plan regarding the Intergrain UltraDeck. In regards to the screws, I recommend using two per joist. Please remember to put an allowance of 15mm from the edge of the panel and drill pilot holes and countersink to prevent splitting the timber.

 

If you need further assistance, please let us know.

 

Eric

 

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Re: Deck options

So, I've now planed all the joists where needed.  I can run my level across the joists with ease and I've removed any high spots so the level doesn't see-saw.  Aside from the fact that the level will catch itself on the edge of a joist, it's probably less than 0.5mm, so nothing to worry about.  All in all, it's pretty flat.

signal-2024-02-14-131719_002.jpeg

 

Except for 1. The 3rd last joist (which you can probably tell in the picture, hasn't really been touched by the plane) sits up to 5mm low in some spots.

signal-2024-02-14-131719_003.jpeg

 

Yet, 400mm further down, it's fine.

 

signal-2024-02-14-131719_004.jpeg

 

I had a few of these laying about which I could use to nudge the joist up by a couple of mm to close the gap for any section of joist that is over the concrete.  However, the span that isn't over the concrete might be a little tricker.  So, what are my options?

Can I use shims under each decking board on that joist to eliminate the gap?

 

EricL
Bunnings Team Member
Bunnings Team Member

Re: Deck options

Hi @IronStan001 

 

Using plastic shims would be the easy option, you could make your own timber shims but that would take a while and they would shrink in time, whereas the plastic shims would retain their shape.

 

If you need further assistance, please let us know.

 

Eric

 

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Re: Deck options

Yeah, I thought about making my own shims from offcuts, but considering how thin they be, they might be a little fragile.  Otherwise a box of https://www.bunnings.com.au/macsim-140mm-assorted-packer-window-100-bucket_p0091691

...should do the job.  I should be able to trim a tiny bit off the shim so they're not noticeable under the 140mm board.

 

With regards to the oil (again), oiling the underside of the boards is recommended.  How do I go about that?

 

Do I give the underside the full prep process?  Or can I give each board a healthy coat of oil (assuming I'm using non pre-oiled boards)?

EricL
Bunnings Team Member
Bunnings Team Member

Re: Deck options

Hi @IronStan001 

 

Just keep in mind that if there are any tannins or chemicals weeping out of the decking panel it will push the oil off. So, it's important to make sure that the decking panel is dry. I suggest putting some cover sheets on the concrete base just in case the oil drips from the panels. 

 

If you are keen to coat the underside, I propose giving the panel the full prep process before coating it with oil.

 

If you need further assistance, please let me know.

 

Eric

 

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