paving advice roadbase or concrete base?

[ceaser]

I am getting ready to pave my court yard about 45 sqm.<o></o><o></o>
I am tossing up whether I should lay roadbase or lay concrete as my base<o></o><o></o>
Fairly good soil free from clay, on the assumption that the current concrete has not cracked (about 7 years old, came with house)<o></o><o></o>

The area will be used for pedestrian traffic only - no cars at all<o></o><o></o>
Had a few quotes some are saying road base is fine, others are saying to lay them on concrete base<o></o><o></o>
What is the right way?
Any comments<o></o><o></o>

[Bleedin Thumb]

Road Base should be sufficient. 100mm thick compacted to 75mm. Spend some time wetting and compacting it with a flat-plate compactor, a vibrating roller is even better.
I find recycled RB not only cheaper but compacts better. Make sure you get equal to DGB20 or your wasting your time.
Use your roadbase to get the falls etc so then you can use minimum bedding sand over it. 25 - 50mm max.

[Sir Stinkalot]

Road base would be the way to go if there is nothing there to start with. Do you have a concrete base already in the area you are planning to lay pavers.

[TEEJAY]

My 2c worth.

I have laid plenty of pavers on compacted sub-base and similarly over concrete. In both cases I have put fine sand in the gaps to help bed it all in.

Above works great for traffic and stability on sub-base of compacted fines such as quarter minus or well graded sand or small gravel.

The only problem i have found is that ants set up camp under the pavers and in doing this lift the sand as quickly as I can put in in place again and this is regardless of whether the pavers are on concrete or compacted fill.

The pavers I presently have I will lift and re-lay with glue to the concrete and grout between similar to brickwork. This will give me a paved surface that will not let ants in and similarly weed seeds won't take root between the pavers. Looks good too. More difficult, more expense and time but oevr years of service in my opinioin the best way to go.

As for the area I am to do as described above I have near 250 sq m - should keep me busy for a while. The amount to be re-layed is about 50% and the rest is currently concrete base awaiting glued pavers.

The other benefit of gluing and grouting is the pavers don't butt up against each other so they do not have to be the best grade and this lends itself to buying the half-price seconds when they are available.

[Bleedin Thumb]

one benefit of segmented pavers is that you can lift and relay them if you have to say lay a conduit under in the future. You lose that advantage if you glue your pavers.
If you lay pavers over a slab you have to lay them on a sand/cement mix anyway.

Because you have to mortar your outside pavers to the slab ( for strength) you create a bucket effect so rain will eventually fully saturate your sand causing the pavers to "float" somewhat. You get a point load on your pavers ( apersons weight can be enough) and it will force water out of the joints, but with the water also comes a bit of sand so the paver will never settle back to level. After a while it looks very uneven.

Cement in your bedding sand prevents this. It also prevents ants digging up the sand.

[TEEJAY]

one benefit of segmented pavers is that you can lift and relay them if you have to say lay a conduit under in the future. You lose that advantage if you glue your pavers.
If you lay pavers over a slab you have to lay them on a sand/cement mix anyway.

Cement in your bedding sand prevents this. It also prevents ants digging up the sand.

If pavers are glued down they are there to stay, but if you lay concrete under the pavers it is there to stay as well and not easy to lay services underneath.

Two problems I have seen with mixing the cement with sand to sweep into the gaps is it leaves a fine cement film over the pavers (best way to remove this - acid or water blasters damage the pavers or lifts out the mix swept in) and secondly it makes the pavers more difficult to lift if you wish to get under them for any reason. Seems a half baked solution from my experience - perhaps others have success with this and some useful tips? I'll never use a sand cement mix with pavers again.

[Rookie]

A small hijack, but just a small one. When I lived in Perth, we laid all our paving over compacted yellow sand (brickies sand). Mortared the side rows in a swept dry yellow sand into the cracks to set the bricks in. That was all. Never had any problems.

Now I live in Melbourne I see everyone using road base, or other semi permanent solutions under paving, and have to wonder why. I know brickies sand was real cheap in Perth because you can dig it up everywhere, but does any of the more experienced, or professional pavers, know why this method isn't used in Melbourne, at least as far as I've seen?

[Bleedin Thumb]

Two problems I have seen with mixing the cement with sand to sweep into the gaps is it leaves a fine cement film over the pavers (best way to remove this - acid or water blasters damage the pavers or lifts out the mix swept in) and secondly it makes the pavers more difficult to lift if you wish to get under them for any reason. Seems a half baked solution from my experience - perhaps others have success with this and some useful tips? I'll never use a sand cement mix with pavers again.

Hi TeeJay.
No I was talking about a sand/cement bedding mix, not the sand that you sweep into the sand to get Lock Up.
I don't much like using cement in the sand either but as I said if you are going over a concrete slab you have to.
Cement dust shouldn't be a problem on your pavers either all you do is wash it off immediatly with a fine mist spray.
We used to do radiating paving that we would pour a slurry over to fill the gaps and used the above method so that very little cleaning had to be done the next day.

[journeyman Mick]

Rookie,
just a guess, but from what I've heard most of Perth has sandy soil, which would be very stable. Melbourne, on the other hand, is clay and some of it is quite reactive so I'm presuming more preparation is required.

Mick

[Rookie]

You're right Mick. It is mostly sand. We didn't even have to install storm drains there. Just put the down pipes into a 4 foot concrete soak well and let it soak away.

The clay must be the reason. Pity, 'cos I've got about 50sqm to do this winter for a BBQ area and I really hate that road base, white sand, mucking around rubbish.

[ceaser]

If i have concrete do i still have to lay 25 mm of sand or cement them in place which is better.

[Bleedin Thumb]

Ceaser, use sand cement mix Get it premixed from your building supplier.
1 bag of grey cement per tonne of paving sand is plenty. It means that you should only order what you are going to lay that day so get some mates over because its best to do the whole job at once.

EDIT I am talking about your bedding sand that goes over your (blind) concrete slab.

[markclad]

When i have seen shopping centre paving done as an example, its on a concrete base then 25mm sand screed. this would allow for your concrete to be a little rough.

[falcon]

Lots of advice here for you Ceaser but for my 2c worth. I did a driveway myself 170m2 in total so a big job. I put down deco (decomposted granite) first as a base to fill in as i had to dig out some rock in areas. I then used crusher dust for a leveling base, sprinkled some cement dust on it and layed the pavers directly on top. Less sand that way for ants to dig through. Only used sand to sweep over the pavers at the end.

I really can not see the sense in laying concrete first to then paver over. Why not just colour or stencil teh concrete as you go.

The big reason I paved my drive was that I could do it myself over a period of weeks. if i used concrete would have to pay someone to do it.