Hoping for advice on my paving project

[Prodigy]

Hello, thanks for looking. I'm working on my garden, and would be grateful for some help.

The main thing is there is a small central lawn area with a large concrete path going right round it. I want to fill it in, make it on a level with the path, then pave the whole lot. I've dug the earth out down to about four inches, and the surface is nice and level, tightly packed. I think it could go down a little more, but is that necessary/would it do any harm to have a layer of earth below the hardcore?

I was thinking of just putting down damp-proof membrane now, whacking my hardcore on top, blinding it with ballast, then putting the concrete on. Is that a good enough approach? (Oh yeah, have I got it the right way round with the DPM?)

I'm planning on using loads of broken bricks I have lying around for the hardcore, will that be okay? The biggest pieces are a quarter of a brick in size - should I break them down more?

The other thing I wanted advice on is mixtures, as it's been years since I've done anything like this, and I was ever the novice. I was planning on using ballast and cement for the concrete - is that right, and what ratio should I use please? As for the bedding for the paving, I'm not sure what to use.

Lastly (for now ) how smooth does the concrete need to be before I put the paving down. In general the whole lot will be about as level as you can get, but there are areas of the path that are quite rough & have ever so small ridges here and there. Is it worth the extra cost and work to put down levelling compound?

Thanks very much!

 

[DJM]

Not sure of the etiquette of pointing to another web site, but there is a really good site covering virtually all paving support http://www.pavingexpert.com where you will find advice recommendations and mixing guides. It is a large site and very comprehensive, but served me in good stead when I laid the front drive.

 

[noseall]

if the maximum loading is only going to be pedestrian traffic, then what your saying sounds ok.
so long as you've removed the vegetable matter and there aren't any soft spots then ok.
if you think you may need a soak away for drainage at any time, now would be a good time to do it.
so this would be how i would tackle it:
remove soil etc.
lay down permeable root barrier.
lay down and compact 100-150mm hard core.
lay slabs/paving directly onto the compacted hard core using sharp sand/cement ( 5 sand 1 cement).
i always solid bed slabs rather than spot. more work getting them level, but after a few hours you can walk on them and finish the pointing.

 

[Prodigy]

Cheers both of you.

Noseall, is permeable root barrier another name for DPM or is it something else that I should use? Tried an internet search on it, but there's only a couple of obscure references on scientific sites that don't shed any light to me.

 

[noseall]

dpm is non permeable and is commonly used internally to prevent the ingress of damp through a floor slab.
hence, damp proof membrane.
root barrier allows rainwater to seep through and is an ideal out door product. its sold at builders merchants and garden centres.
usually black. 1.5mx50m rolls. or buy per length.