How to pour concrete for a sloping driveway?

[aledld]

Hi,
I am in the final stages of creating a sloping driveway. All of the preparation has been done and I just have the ready-mix to book. When I come to poring the concrete should I start at the top of the slope and work down or start at the bottom and work up?

Once the concrete has been put down and levelled do I need to seal it?

Thanks in advance

Aled

 

[mrnigelhudson]

Recruit enough help to do the job. Pouring concrete takes a lot of muscle and endurance, as you work against the clock to smooth it before it hardens. Be sure to have plenty of people available.
Adjust the moisture content of the concrete. When the driver arrives on your property, ask to see the texture of the concrete. He will release a small amount down the chute for your approval. It will be on the dry side. He will add shots of water at your request. You want it wet enough that it does not harden too quickly.
Pour the concrete into the formed area. Push the chute back and forth to allow the concrete to reach the edges. Ask the driver to pull forwards or back up to accommodate you.
Shovel and pull the wet concrete to the edges of the form. All assistants must now help. Instead of using the shovel in a digging manner, reach out with it and allow it to fall on its backside on the concrete, sinking in slightly and then pull it towards you.
Screed the wet concrete after you obtain a rough level. With at least one person on each end, position the screed at the highest end of the pour and work downwards. All concrete has a slight slope to allow for drainage. Repeat one to two times to achieve a level finish.
Float the concrete with the bull float as soon as it has hardened enough to allow the float to move easily over the surface without sinking in. In a straight forward and backwards motion, push and pull the float across the wet concrete. When the concrete is relatively smooth, switch to the finish float to fine tune the surface.
Use hand trowels around the edges to tamp the concrete securely against the forms. With the edge trowel, work it back and forth between the form and the concrete to create a clean, rounded edge. There is no need to seal the concrete when dry.


Nigel

 

[noseall]

Start at the furthest point away from the position of access.

If you have all round access make sure you fill a section before tamping to avoid slumping.

Don't forget ex-con joints if necessary.

 

[^woody^]

Start at the bottom. You don't need to seal it. Leave a rough surface finish if you don't want a slip hazard

 

[SimonH2]

So we have "start at the top", "start at the bottom", and "start at the furthest point".

As a novice, I'd say :
Start at the furthest point, unless there is somewhere other than in your new concrete area for the wagon to drive. When we did something similar at the gliding club, the wagon could drive alongside our concrete area and fill it from the side - for a domestic drive, I'd imagine the only place of the wagon would be where you are about to concrete (unless it's short enough to reach with just an extension chute).

But, I'd say make sure that you only have to move concrete downhill ! If the slope is down towards the road, then start with excess at the top so you can level it downhill as you go. If working uphill towards the road, then make sure you don't dump too much to start with as you'll be shovelling it uphill.

One thing we got wrong at the gliding club was that, IMO, we had it too wet and were laying it on a very porous surface with no membrane. Got it levelled off, and quite quickly it started showing crevasses as the water drained out of it. Luckily one of the people around fetched a power float from his workshop and worked it back into one slab again before it set.

 

[^woody^]

You never start any building work at the top of a slope

Concrete will slump down a slope if it's not laid from the bottom

 

[Norcon]

Off loading the concrete usually dictates whether you start at the top or the bottom.

Starting at the top means its easy to pull a vibrating screed downhill.
Thats how my own lane way was done which has about a 12% grade. Then fine bristle, brush finished across. Probably a bit smooth though.
You let the concrete out very stiff and the vibrating screed does the rest.

 

[fmck]

I don't think it would make much a difference either top or bottom but certainly tamping/roller/ vibrating screed top to bottom. We poured a concrete road for a very heavy vehicle on Friday and next week a gas storage yard all sloping and its top to bottom pouring with them. It's just the way they want to do it.

 

[SimonH2]

Starting at the top means its easy to pull a vibrating screed downhill.

That was what I was thinking - it's easier to pull things downhill than up.

Thats how my own lane way was done which has about a 12% grade.

And of course it does depend on the slope. I'd imagine steep slopes are tricky to do whichever way you go.

 

[noseall]

I'd imagine steep slopes are tricky to do whichever way you go.

They are and this is where timing is important.

You need to allow the conc to stiffen so that it behaves but still wet enough so that it allows you to work the surface.

 

[aledld]

Thanks for all the advice. Mix delivered tomorrow so lets hope for a dry day!