Low-level deck for backyard

Hi,

I’m building a deck on my alfresco, which is extended few mitres in the lawn area too. The size of the deck is 4.5 x 4.2m. Alfresco area covers the length of 3m and remaining 1.2m is in the lawn area. It’s a low level deck as the max height I can go is around 160mm. I’m using 11x90x45mm joist across 4.5m, with side boards(90x45mm) covers all the edges of the rectangle, these are screwed together using baton screws(75mm). Joist are sitting on the pedestal( Buzon, which can bear more than 1000kg), each joist are sitting on 5 pedestals, 30cm from both side and 3 in the middle spaced evenly. 3 Pedestals are sitting on the concrete Alfresco, 2 pedestals are in lawn area and sitting on the bricks, these bricks are laid on concrete which I freshly did for this project.

I got few questions and need help from the DIY community:

1) At the moment deck is very stable. But do I need to fix few joists in alfresco area to the concrete using L brackets to avoid any movements in deck in future.

2) Do I need to put a post in the lawn area, may be 3, and fix the edge 90x45mm frame using as a bearer to give more support to the joists, these joists are already connected to it using baton screws.

3) any other suggestions

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

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Comments

EricL

Hi @siran

Welcome to the Bunnings Workshop community. It's amazing to have you join us, and thank you to sharing your question about your low-level deck.

Your timber framework looks excellent. I see you've used adjustable pedestal feet to keep your deck frame nice and level.

Let me try and answer some of your questions:

Using "L" brackets is a good option to keep the timber frame from moving. The other option is to drill your frame to the side of the house. On the condition that the mounting point is big enough for a ledger and that the joists are attached with joist hangers.

With the way that you've laid out your pedestal feet, it's not necessary for you to put a post in the lawn area. If you've used 12g to 14g batten screws these should be sufficient to hold it in place.

My only other suggestion is to put weedmat and gravel under the deck to help facilitate drainage.

It's a fantastic low-level deck project, we look forward to seeing it assembled and complete.

If you need further assistance, please let us know.

Eric

siran

https://www.workshop.bunnings.com.au/discussion/comment/17859#Comment_17859

Dear Eric,

thanks for your guidance. I prefer L bracket than attaching the deck to the side wall as I already used batten screws instead of joist hanger. Further, do I need to spray any chemicals to lawn area to prevent weed or lawn growing in the deck area ? if so what product you can recommend? Or laying a weedmat is sufficient.

thanks

EricL

https://www.workshop.bunnings.com.au/discussion/comment/71572#Comment_71572

Hi @siran

There is no need to spray chemicals, the weedmat and gravel will be enough to kill the turf underneath.

If you need further assistance, please let us know.

Eric

siran

https://www.workshop.bunnings.com.au/discussion/comment/99071#Comment_99071

Hi Eric,

Do I need to use joist protector? I cannot see most of the deck work shared in DIY community using joist protector. In my case, only part of the deck will be exposed to wet weather.

Thanks

MikeTNZ

Just a question, if I may, siran?

What are them black coloured supports under the deck bearers?, I've never seen them before, are they commonly available?

I've also never seen a deck with ex.100 x 50 mm bearers either, in the last couple that I've built, they've used ex.150 x 50 mm bearers, however,

given the amount of supports you have under them, I can't see a problem.

I'd love to see this when it's finished, it looks like it's going to be great.

EricL

https://www.workshop.bunnings.com.au/discussion/comment/116333#Comment_116333

Hi @siran

Any extra protection you can provide your deck is always a plus. So if you can fit it into your budget, I would put the joist protector on. There's no need to put it over the covered area only the exposed part of your decking frame.

If you need further assistance, please let us know.

Eric

EricL

https://www.workshop.bunnings.com.au/discussion/comment/17900#Comment_17900

Hi @MikeTNZ

Let me tag @siran to make them aware of your questions. I believe siran used adjustable pedestal feet in combination with bricks and concrete to support the joist.

Eric

siran

https://www.workshop.bunnings.com.au/discussion/comment/17900#Comment_17900

@MikeTNZ

Hi Mike,

I used adjustable pedestal to support the joists. The joists I used are 90x45mm as I got max height of 160mm in alfresco area, so added more footing to support 90x45mm.

thanks

siran

https://www.workshop.bunnings.com.au/discussion/comment/71588#Comment_71588

Hi Eric,

unfortunately the merbau boards (90mm) I got are not straight, I’m seeing 20-50mm curve in all the boards and I’m using clamp to fix these, sometime I’m cutting the boards to small length. My question is that if I use clamp to fix these, would that be a problem in future that screws will not hold it over time or due to weather changes and timber shrinks and expands etc

thanks

EricL

https://www.workshop.bunnings.com.au/discussion/comment/99104#Comment_99104

Hello @siran

I'm sorry, but it is the nature of wood to turn and bow. I suggest a combination of Grunt 25mm x 3m Ratchet Tie Down Straps - 4 Pack and Clamps to persuade the timber decking to fit into position. I suggest placing one of the bowed pieces every so often on the run and not right next to each other. You'll then be able to space and straighten that piece next to one that is actually straight. There should be no issues in the future once the bowed piece has been secured to the frame. In time the forces applied by the screws and the exposure to the elements will straighten the panel out.

If you have any other questions we can help with, please don't hesitate to post them.

If you need further assistance, please let us know.

Eric

siran

https://www.workshop.bunnings.com.au/discussion/comment/116341#Comment_116341

Hi Eric,

Im almost completing the project. I have concern on the merbau panel bought from Bunnings. These panels are pre oiled, but after 2 days rain, panels are faded. What should I do for durability.

Further, I’m planning to install fascia boards, I’m not sure which boards to use considering the airflow underneath the deck. I hope I need to have some clearance between deck fascia board and ground.

thanks,

siran

MitchellMc

https://www.workshop.bunnings.com.au/discussion/comment/126223#Comment_126223

Hi @siran,

Your Merbau boards are pre-oiled to get from the manufacturer to you. What you see here is part of the weathering process before applying your oil to the deck. This is a good thing. You can either wait 6-8 weeks for the natural weathering process to complete, which strips the tannins from the timber or use Cabot's 2L New Timber Prep to accelerate the process. Once this weathering is complete, you'll apply two coats of Merbau decking oil.

I'm a few weeks ahead of you in the process, and my deck had been weathered for four weeks, and then I used the new deck prep as I didn't want to wait any longer. I've just applied my first coat of actual decking oil, and it looks fantastic. My deck looked exactly like yours after I'd first laid it due to all the rain we've been experiencing in Sydney.

You usually use a board slightly wider than your frame for the facia board. For a 90mm frame, you'd use a 140mm board.

Please let me know if you have further questions.

Mitchell

siran

https://www.workshop.bunnings.com.au/discussion/comment/132797#Comment_132797

Thanks, finally the work is completed. Only stain and oil are pending.

EricL

https://www.workshop.bunnings.com.au/discussion/comment/136850#Comment_136850

Hello @siran

What a beautifully built deck. Thank you so much for sharing your photos from the frame up to the deck panel installation. I'm sure this project will inspire a lot of our members to give this project a go. Now that it is built, would you have done anything differently in hindsight? What would your number one tip be to our members who might want to replicate your project?

Again, thank you so much for taking us along your D.I.Y. low-level deck journey.

We look forward to seeing your next project.

Eric

siran

https://www.workshop.bunnings.com.au/discussion/comment/139619#Comment_139619

Thanks Eric. Lot of patience required when fixing the panels. If I had more budget I would go for Eko deck panel, I hope it would reduce effort required to fix panels.

Jason

https://www.workshop.bunnings.com.au/discussion/comment/141513#Comment_141513

Hi @siran,

Hope all is well.

Thanks again for sharing this project with the community - it has been very popular with members and visitors to the site. Our team is keen to feature your project. Do you have some photos of the finished and oiled deck you could share?

Thanks again,

Jason

chrislcoss

Hi there. Your deck looks great and is very similar in format to what I am looking to do at my place. Can I please ask how deep you dug your footings? OR, if the Bunnings rep could suggest depth for a deck such as this?

MitchellMc

https://www.workshop.bunnings.com.au/discussion/comment/34961#Comment_34961

Welcome to the Bunnings Workshop community @chrislcoss. It's sensational to have you join us, and many thanks for your question about deck footers.

Typically these adjustable pedestal feet just need to be placed on a compacted surface and no actual footer is required. To spread the load, you might like to place a paver under them, or in @siran's project, it appears they've poured some concrete and bedded bricks into it. Hopefully, now that I've tagged them, they'll be able to let us know whether they created a full-depth footer.

Depending on the soil in your area, it might be worth touching base with your local council to find out whether significant footers are required to offset instability.

Please let me know if you have any questions.

Mitchell

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