Concrete advice

[EvilDonut]

Making a concrete base for some brick/stone steps outside my front door.

Need 50mm concrete on top of my compacted hardcore. Area roughly 2.8m x 1m. Worked it out as 28 pre-mixed bags (20kg bags).

Are bags the right way to go or should I be buying bulk aggregate? (would prefer not as delivery is a pain)

Is it too much to mix in a barrow, should I rent a mixer for a day?

Should I lay some rebar or not bother?

 

[John D v2.0]

0.14m3 - would be doable by shovel but you'll need a strong back especially if you're using separate cement powder.
The pre mix will be more costly and will need storing in a dry place but no need to faff mixing them and adding plasticiser. The separate is cheaper and you can leave the sand outside for ever. But a bulk bag is about 0.5m3 so it'd be those small bags anyway.
So save on the cost of a mixer and get the pre mixed dry bags seems most economical if you've a good back.
No idea about the rebar, not sure how it would work in a 50mm slab. Your hardcore will be well compacted and providing the strength

I've only ever mixed small quantities by hand for drive haunching the edging and other small jobs like repointing, and bedding wall plates. And I use the separates because I am like a messy cook and like experimenting with mixes

 

[Ian H]

I'd use 25kg bags of ballast and cement, mixed in a mixer.

 

[EvilDonut]

Yep ballast looks much better.

Mastercrete concrete bags * 28 = £168

All-in-ballast * 28 + cement* 6 = £78

It’s a no-brainer

Still not sure about the mixer though. Seems a bit overkill for that amount. How many bags per hour could someone mix in a barrow?

Can I just use fairy liquid as plasticiser?

 

[tomfe]

You don't need a plasticiser for concrete, you should not be putting fairy liquid in with any concrete.
It's about 20 wheelbarrows you'd have to make. 12 with a mixer.
I'd get a mixer with that £90 you are saving.

 

[Doggit]

Mixing that lot in a barrow etc will do your back in, so what you save on the mixer, can go towards the osteopaths costs.

 

[Ian H]

If I'm mixing more than 12 I get a mixer.

28 and I'd be looking by for a new job.

 

[chappers]

Mixing that lot in a barrow etc will do your back in, so what you save on the mixer, can go towards the osteopaths costs.

Everyone's going soft in their old age. I've lost count of the amount of concrete and mortar I mixed by hand for my old man when I was a kid and you've got a wheelbarrow too you don't know you were born. the first load of concrete I mixed was to cast a slab to basically mix concrete and mortar on. It seems like I spent every weekend for about two years mixing concrete and mortar.

 

[Doggit]

And you've obviously forgotten how knackered you were the first few times you did it. On the other hand, you're totally right.

 

[John D v2.0]

When you see a load of people in the gym paying good money to row/lift/etc while staring at a TV it makes you wonder why they don't go home, get better exercise for free and get a decent new drive for the cost of the materials!
Fittest I've been was the day we finished our block paving.

 

[Ian H]

 

[EvilDonut]

Haha!

Well, as it turns out my mate has a mixer anyway, so I’ll borrow that for the price of some beer.

He thinks my 50mm is too shallow for the aggregate to settle and that I should go with 75-100mm. Sound right? Anyone else tried a 50mm slab for light use?

 

[John D v2.0]

50 won't really have much strength of its own against movement or settlement of larger areas, but as long as your hardcore base doesn't move it'll be a good base and prevent small areas moving.
Is any of the ground made up underneath or is it all uniform boring Virginia ground?

 

[Doggit]

I agree, if you've got a compacter, then 50mm would be okay, but without one, 50mm may not survive on the 2.8m length, but 75mm should be okay.

 

[John D v2.0]

Also another thought, how deep is your hardcore? From memory 75-100mm is the minimum to lock together to spread the load enough to provide the strength.
We used 100 minimum for our drive (had to make up more in places with tree roots and on the slope etc) and did a lot of compaction, and it's been solid enough.