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Merbau decking over concrete slab

Neo19
Making a Splash

Merbau decking over concrete slab

IMG_20191207_141119.jpg

 

Hi Everyone 

 

I have been going through these discussion boards for a while and finally mustered to courage to post a question here :smile:

 

This would be my first deck. Have done some landscaping for myself in the past including a raised garden bed, however nothing major. As far as tools, I've a drill kit including hammer drill, a cordked circular saw and a random orbital sander. 

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My proposed deck would be 350 x 370 with height from the slab between 17 - 18 cm so it stays flush with the brick and same level as my internal floor. 

 

I've been advised that i could use H3 structural timber (140 x 45) as joists and lay decking boards on top that. 

 

My questions, 

 

1. How do I attach joists to the concrete? Use galvanized angle brackets like this?

 

2. How can I adjust the height so the finished decking board stays flush? If i used 140 board + .5 bracket + 19 mm board = it would be around 165 cm height. Which is around 1.5 cm lower than bricks. Can I use plastic wedges / window packers to compensate for around 1.5 to 2 cm? 

 

3. This deck would be under alfresco cover and under eaves. In terms for water drainage, what would be helpful. Would the packers / wedges mentioned in Q. 2 help with the same?   

 

IMG_20190916_143835.jpgAlfrescoAlfrescoRough plan showing pillarRough plan showing pillar

On the last image, pillar is on the corner of the alfresco slab and the decking to the south of it would be on top of soil (this would 370 x 45 cm). Not much height difference from alfresco slab. What do I need to provide here under joist for support? Not enough height for a stirrup. 

 

Thank you very much for reading through. 

asb924
Growing in Experience

Re: Merbau Decking over concrete slab

So I took some inspiration and tips from this post and started my deck today. I'll post all the products I used soon. Needed to stay as low as possible so used 70mm joists. Finished the frame today and the ekodeck goes on tomorrow. Thanks to everyone who contributed to this post, gave me the confidence to take this project on myself. I'll post photos of the finished product tomorrow.

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MitchellMc
Bunnings Team Member
Bunnings Team Member

Re: Merbau Decking over concrete slab

Welcome to the Bunnings Workshop community @asb924. It's sensational to have you join us, and many thanks for contributing your decking project.

 

Absolutely amazing work digesting the information and constructing an ideal frame! I love what you've done there. Those double angle brackets on the end of the joists are a novel idea too. Was that just for rigidity for the counter-levered section? Great thinking of having the bolt run right through the timber connecting the two brackets. I'll have to pinch that idea in the future. Depending on the height of the counter-levered section above the tiles, if you can manage to clad the frame ends in with a board that doesn't physically touch the tiles, you might achieve an awe-inspiring floating look to the deck. That would look brilliant.

 

I'd encourage you to start your own discussion post as well about your deck so you can document the entire process.

 

Many thanks for sharing, as your deck is shaping up to be the perfect example for other members to reference.

 

Mitchell

 

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sachraj
Getting Established

Re: Merbau Decking over concrete slab

Hello  @asb924 

woild love to see your final result..

also , would you mind sharing the link for the joist you used.! Thank you

asb924
Growing in Experience

Re: Merbau Decking over concrete slab

sachraj
Getting Established

Re: Merbau Decking over concrete slab

@asb924 Looks really great.!!

would you have a link to all the other products you used?

also how did you finish your edges?

 

EricL
Bunnings Team Member
Bunnings Team Member

Re: Merbau Decking over concrete slab

Hello @sachraj

 

Let me tag @asb924 so that they are made aware of your questions. Just to help you with the deck materials, they used Treated Pine Outdoor Timber Framing 70 x 35mm for the frame. It was mounted to the cement floor using Galvanized Angle Brackets. The bracket size will depend on the height that you want your frame at. To attach the bracket to the cement floor you can use DynaBolts. To join the timber frame to the bracket you'll need to use Zenith Hot Dipped Galvanised Hex Head Bolt And Nut in combination with Zenith Hot Dipped Galvanised Washer. The size for these pieces will be based on the size of the angle bracket and the thickness of the timber.

 

Looking at the photo that was posted, I don't see any mounting screws in front of the side panel. This look can be achieved by using Ekodeck concealed fixings. If you are building a similar decking project, please keep us updated. Any photos you can post while building it would be much appreciated.

 

If you need more advice or information, please let us know.

 

Eric

 

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asb924
Growing in Experience

Re: Merbau Decking over concrete slab

Nailed it @EricL thanks for that, was everything I used.

Re: Merbau Decking over concrete slab

@Usman 

 

What is that green and black color on your joist shown in picture? Also did you go with 140mm board or 90mm board. I have 120mm ground clearance as well. 


Thanks,
Nauman

Re: Merbau Decking over concrete slab

Hi @asb924 

 

Great work and I am about to start my project as well. Few questions here

 

1- How much is the distance between the last two joists and specific reason to keep some clearance from the left wall?

2- How did you mount blocks between joists as some of them are not screwed

3- No bearers are used here. Any specific reason? 

Thanks

Re: Merbau Decking over concrete slab

Heya @DIYImpressions,

 

The last 2 joists are 70mm (the size of the joists turned on their side) apart because I did a picture frame/border and this worked. I also wanted to keep about a 45mm gap from the wall for drainage etc. I could have bolted one side to the house brick but I couldn't do that on the retaining wall side so did both the same.

 

The blocks were all screwed. I did the joists close to the walls first and then screwed the blocks in and then after the second joist went in I screwed them from that side, they were all to support the border.

 

I didn't do bearers as I needed the deck as low as possible, so height was an issue. I spaced the joists accordingly and probably over did it on the number of brackets per joist but did extra to be safe.

 

Let me know if you have more questions, good luck.

 

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