Indian sandstone - concrete subbase.

[rmim]

Hi All,

I have come across this wonderful website which is highly detailed and scientific - I trust it.

Sadly I cant convince my dad to follow it and he wishes to use his own method.

There is no convincing him to use a type 1 sub-base he wishes to use concrete.

The area we are coving are front drive for car (24m2), side entrance (15m2) and back garden (18m2).

he wants to:

1. Newly laid concrete sub-base.
2. Cement bedding layer
3. Indian sandstone 24mm thick - 3 sizes.


How do we get the above to work - various depths and mix ratios?

Thanks.

[PavingSuperstore]

Aside from the base (you will get opinions both ways on this one, but Type 1 sub-base is more commonly used these days), are you planning to use the 24mm sandstone for the driveway as well? If so, this may cause you problems. Some brands of paving suggest that if you lay the paving on an uprated 100mm wet mortar bed this will offer some protection against cracking, however it may be better to either use block paving in concrete or natural stone (perhaps to match in the paving flags elsewhere) or if it helps, we now have a range of 50mm sandstone suitable for driveway applications that would be better suited than a 24mm calibrated.

So in summary, you started with one problem and I've now given you something else to be concerned about!

[rmim]

So in summary, you started with one problem and I've now given you something else to be concerned about!

Thanks for the reply - Did not see that one coming.

[London Stone Paving]

RMIM

There is a common misconception that a concrete base is better than MOT Type 1. IMO its not, and there are a variety of reasons behind that. It looks as though you are aware of this yourself aswell.

I like to think I am an expert in this subject but even my dad completely ignored all my advice when he had a patio laid about 8 years ago. It was relayed about 6 weeks ago, this time to my specification (by a brew cabin contractor) and I can guarantee it wont need relaying in 8 years. Anyway point is if your dad wants to go down this route then its going to be really difficult to change his mind:

As for your specifications

1. If the back garden and side entrance are not taking vehicle traffic then 100mm concrete will be fine for the sub base. The driveway would need to be a minimum of 150mm and need to include reinforced mesh

2. The bedding layer mix should be 5 or 6 parts sharp sand to 1 part cement.

3. Would also recommend using a bond bridge on the backs of the slabs for the driveway to aid adhesion between the slabs and the bedding layer. A bond bridge is SBR, cement and water mixed into a slurry and painted onto the backs of the slabs. Avoid getting it on the faces of the slabs because its impossible to shift. Also put 100ml of SBR in each mix to further aid adhesion

4. I would also recommend sealing the driveway area with an impregnator. Sealed stone is much easier to maintain, especially important on a driveway

5. Because its a driveway, choose one of the harder stones from Kota, like Autumn Brown, Raj Green or Kandla Grey. Do not go for a mint or rainbow or teak stone

Hope that covers it, any more questions just shout up

Steve

[London Stone Paving]

Are you planning to install yourself or have you got a contractor lined up?

[rmim]

Hope that covers it, any more questions just shout up

Steve

Thank you very much Steve, for the detailed reply.

[Tony McC]

How to lay driveway flagstones - this page

We are supposed to be doing a case study on this very subject, documenting and filming the step-by-step construction of a flagged driveway as it goes down, but there seems to be some cock-up/delay with the job which has not been fully explained to me. It was scheduled for late June but *still* waiting for a confirmed start date.