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What concrete mix for outdoor kitchen concrete benchtop?

indi
Finding My Feet

What concrete mix for outdoor kitchen concrete benchtop?

Hi Team, I'm building an outdoor kitchen and planning to build concrete countertops. Youtube videos shows many options which are bit overwhelming. Can you please suggest concrete mixes I can use? Trying to achieve a smooth finish. Thanks legends!

snowgoose62
Growing in Experience

Re: What Concrete Mix for Concrete benchtop?

Thanks Eric,

1. Could you unpack what you mean about the timing of the pour?

2. I plan to create benches in-situ for our bbq kitchen under patio. I may have wrongly assumed that the self-leveling floor stuff would leave a better finish, as its probably got smaller grains that normal cement/concrete mixes, thoughts?

3. And you mentioned in another post that grout is a good option also, what is the main differences here betweeen grout, floor level mix nad concrete mixes?

4. Thanks for info on the reo, I did see others using a fibraglass plastic roll for reo, so assumed that steel gutter guard or vermin guard on cups to hold up could be an ecomical way of providing strength?

5. What thickness would you recommend? I was thinking 50mm at the edges in 100mm and 30mm for the rest?

6. Yes I do all my own work, so i'll take a series of happy snaps on a timeline and share once done :smile:

Thanks again Eric, any direction on the above is most welcome, I spend near every Sat at my local O'connor bunnings buying stuff for projects, so your good advice is welcome, cheers!

Glenn

EricL
Bunnings Team Member
Bunnings Team Member

Re: What Concrete Mix for Concrete benchtop?

Hi @snowgoose62 

 

If for example you are using Dingo 20kg Self-Levelling Cement and you wish to put on a thicker application, it must be applied in layers with each layer being no more than 25mm thick. The recommended drying time for this particular product will be indicated at the back of the bag. 

 

The self-levelling cement does have a finer finish and you can even achieve a better finish by sanding the surface of the cement once it has fully cured. Another option is Construction/Structural grout, it has high compressive and flexural strengths. However, it will need to be properly levelled using a tool.

 

I propose reducing the thickness to perhaps 50mm so that the benchtop is not so heavy. But I'll leave that choice up to you. My best advice is to make sure that your timber frame case for your benchtop is very well planned.

 

If you need further assistance, please let us know.

 

Eric

 

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snowgoose62
Growing in Experience

Re: What Concrete Mix for Concrete benchtop?

Thanks Eric, yes was thinking 50mm at edges and 30mm in the rest. How about these for reo?

https://www.bunnings.com.au/strol-0-5m-surepave-plastic-pavers_p3452192

EricL
Bunnings Team Member
Bunnings Team Member

Re: What Concrete Mix for Concrete benchtop?

Hi @snowgoose62 

 

The super pave plastic is more for structural support for pebble driveways. I recommend the Whites 1800 x 1050 x 5mm Light Duty Reo Mesh in combination with Whites 25 - 40mm Plastic Reinforcing Bar Chair - 20 Pack. The Bar chair keeps the reo in the middle of the concrete slab providing support in the middle.

 

If you need further assistance, please let us know.

 

Eric

 

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snowgoose62
Growing in Experience

Re: What Concrete Mix for Concrete benchtop?

Thanks Eric, one more and then I'll leave yu alone. The concrete mix, there seeems a big difference in price i.e.

https://www.bunnings.com.au/dunlop-20kg-construction-grout_p6650143 = 31.40 per 20kg


https://www.bunnings.com.au/westbuild-20kg-40mpa-concrete40-high-strength-dry-mix-concrete_p0760334 = 9.61 per 20kg

 

https://www.bunnings.com.au/westbuild-20kg-general-purpose-concrete_p0760042 = 6.40 per 20kg

 

Given I need approx 800kg, thats 40 bags, I'm leaning towards the last one for obvious reasons, thoughts?

 

Thanks

Glenn

Re: What Concrete Mix for Concrete benchtop?

The difference in price reflects the properties of the concrete @snowgoose62. The cheapest also has the lowest strength and is unsuitable for structural applications. If you were to use it, you'd need to ensure the edges are well supported, and a significant amount of reo mesh is used. If a heavy or hard object strikes any exposed corner, you can expect it to crack. Also, any sharp edges will damage easily and crumble.

 

You can see the construction grout has a hardness of 65MPa, the high-strength concrete 40MPa and the general purpose concrete around 25MPa. When building items like benchtops, it's important to remember that concrete has significant compressive resistance, but the only thing stopping your bench from cracking and collapsing is the reinforcement throughout it. Say you had a 50mm thick concrete slab supported 600mm apart. If you were to strike it with a heavy blow in the middle, it would crack. If you run substantial reinforcement through, it likely won't crack. The higher the MPa of the concrete, the better chances you have of the bench not cracking.

 

If your budget allows it, I would suggest that you at least go for the high-strength concrete.

 

Please let me know if you have questions.

 

Mitchell

 

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Re: What Concrete Mix for Concrete benchtop?

Thanks, Mitchell, gotcha, the bench is for an l shaped bbq outoor kitchen. I want 50mm at the sides, but I think 30mm in the centre will suffice, so I may use another chunk of form panel to take up that 20mm in the middle. Yes, I will go with the stronger stuff, good advice there, cheers!

markw
Building a Reputation

Re: What Concrete Mix for Concrete benchtop?

I just made a concrete tabletop using this concrete: https://www.bunnings.com.au/easy-mix-20kg-55mpa-super-strength-concrete_p0760460 really happy with how it turned out. I made it 40mm thick.

I used the 5mm reomesh https://www.bunnings.com.au/jack-1800-x-1050-x-5mm-light-duty-reo-mesh_p1060321 and made the form using melamine https://www.bunnings.com.au/2400-x-1200mm-16mm-melamine-particleboard-white-matt_p0097412

tabletop.jpg

Jason
Community Manager
Community Manager

Re: What Concrete Mix for Concrete benchtop?

Awesome work @markw. It looks great. 

 

I would encourage you to hit the Start a discussion button and share as much detail as you can about your project. If you've got some in-progress shots, members would love to see them too! I'm sure the community will be really inspired by what you have created.

 

Welcome to the Bunnings Workshop community. I trust you'll get lots of help and inspiration in return for your contributions.

 

Jason

 

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EricL
Bunnings Team Member
Bunnings Team Member

Re: What Concrete Mix for Concrete benchtop?

Hello @markw 

 

Thank you so much for sharing your concrete benchtop project. Let me tag @snowgoose62 to make them aware of your materials list. That benchtop looks absolutely amazing, is the slab free floating with no timber support underneath? What is the size of the concrete benchtop? Do you have any photos of the melamine frame before you poured concrete into it?

 

Any other details you can share about the benchtop creation would be very much appreciated.   

 

Eric

 

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