Workshop
Start a discussion

The Bunnings Workshop community can help with your home improvement projects.

Low-level deck on concrete slab

karim
Budding Contributor

Re: Merbau Decking over concrete slab

@Jithesh , thanks for your post. Very helpful. I am planning similar to what you have done. The only difference is mine will be half over concrete and half over the soil. Keen to see the photo near the sliding doors. Also, keen to know how much space left from the fence?

Reply
Loading...
MitchellMc
Bunnings Team Member
Bunnings Team Member

Re: Merbau Decking over concrete slab

Welcome to the Bunnings Workshop community @karim. It's fantastic that you've joined us, and many thanks for jumping into the conversation.

 

I trust @Jithesh will have some helpful advice for your project. Please feel free to start your own discussion so we can delve further into your project and answer any questions you might have about it. I trust you'll find loads of inspiration just like this project within the community as our amazing members contribute their projects here every day.

 

I'll be looking forward to hearing more about your project and would encourage you to share it with us.

 

Mitchell

 

See something interesting? Give it the thumbs up!
Reply
Loading...
ChrisNocker
Budding Contributor

Re: Merbau Decking over concrete slab

Great work on the list of materials and tools!  It's good to know what you're going to be up for and you can see if you've missed anything :wink:

Just remember with the timber lengths that you can't buy a lenth that is exactly 4m long (probably 4.2m or 4.8m is the closest and depending on stock availability).  And also with the 7m length, timber does not come that long (probably 5.4m or 6m) so you'll have to buy two lengths and join them in some way.  If it were me I'd join them using a half lap joint and coach bolts, making sure the joint is close to the bearer/support point below the joist.

Best of luck.

 

Edit: My comment about the lengths doesn't have as much relivance now that I see there is more than 1 page to this thread... dough.  Looks great though.

Reply
Loading...
MitchellMc
Bunnings Team Member
Bunnings Team Member

Re: Merbau Decking over concrete slab

Welcome to the Bunnings Workshop community @ChrisNocker. It's fantastic that you've joined us, and many thanks for contributing to the discussion.

 

Available timber lengths need to be accounted for in the design stage and can add to the cost of a project if there is going to be significant wastage. It's always something to consider when budgeting. Your suggested method of joining lengths is also a great option.

 

Many thanks for sharing your knowledge, and we look forward to hearing all about your projects around the house and garden. We'd encourage you to let us know if you ever need assistance or have something to share with the community. I trust you'll find loads of inspiration for your projects here as our amazing members contribute their ideas here daily.

 

Mitchell

 

See something interesting? Give it the thumbs up!
Reply
Loading...
aiden
New Contributor

Re: Merbau Decking over concrete slab

Fantastic forum! Cant believe I've only just found it. 

I'm in the process of doing a low ground deck over a concrete slab too. Seeing your questions relate to my situation 100%.

My main question is this: will bolting your treated pine directly onto the concrete increase the chances of rot? 

 

My deck will be directly in front of my front door and only slightly shaded from the elements. How can I keep a low deck while also leaving room for airflow and avoid the timber touching the concrete slab directly? 

 

Thanks in advance :smile: Aiden. 

Reply
Loading...
MitchellMc
Bunnings Team Member
Bunnings Team Member

Re: Merbau Decking over concrete slab

Welcome to the Bunnings Workshop community @aiden. It's terrific that you've joined us, and many thanks for your question.

 

You must leave as much space for airflow and drainage under your timber as possible. Bolting any timber that is not rated H4 and above directly onto concrete will reduce its lifespan. If a gap is not left, moisture will constantly be trapped, which starts the rotting process. Deck structures are commonly constructed from H3 outdoor framing timber, which is suitable for aboveground use. It is not suitable for in-ground or in direct contact with the ground.

 

You might like to start your own discussion so we can cover your project more extensively. If you include some area images, a sketch of your deck plan and details on the height between the concrete slab and the door sill, we can further discuss what options are available.

 

Mitchell

 

See something interesting? Give it the thumbs up!
Reply
Loading...
aiden
New Contributor

Re: Merbau Decking over concrete slab

Thanks for the prompt response. I'll go ahead and try to take some pictures later on for a separate thread. I just thought that this was so similar I almost didn't need a separate thread.

 

From the deck example in this thread, did you use H4 treated pine directly on top of the concrete slab? Thanks :smile:

Reply
Loading...
MitchellMc
Bunnings Team Member
Bunnings Team Member

Re: Low-level deck on concrete slab

@aiden,

 

I believe @Jithesh use H3 treated pine attached to the concrete slab with L brackets which allowed a gap under them.

 

Mitchell

See something interesting? Give it the thumbs up!
Reply
Loading...
Jithesh
Junior Contributor

Re: Merbau Decking over concrete slab

@karim  - Sorry for the late response. I have built just over the concrete. My concrete ends 20cm off fence and so is my deck. It is flush on level near the alfresco door.

 

Reply
Loading...
Jithesh
Junior Contributor

Re: Merbau Decking over concrete slab

Hi @aiden  I have used H3 treated pine over the concrete as joists and attached to the concrete with L angle brackets as @MitchellMc mentioned already.

Reply
Loading...

Why join the Bunnings Workshop community?

Workshop is a friendly place to learn, get ideas and find inspiration for your home improvement projects