Sub base question

[lemsip1]

Hi

Firstly, thanks for a very useful site on paving.

I have a question regarding sub base and have read all info supplied on the site but cannot find my particular starting point.

We have had a driveway and entrance dug out of Granite rock. The drive is steep and is presently unfinished. The drive basically goes up what was a very uneven granite incline, which has been flatterened with frgments of granite where needed. therefore some parts are solid rock and some are small granite pieces laid onto solid granite. I must point out that the granite is very britle but their are no sharp edges now.

Now my question. We wish to block pave the drive and I'm not sure if a subbase is needed as we are on solid granite or even if its possible to block the area. I had also toyed with using carpet stones but find them too expensive.

Any suggestions as to what surface could be used or laid would be most helpful. The whole area is 125m2

Thanks in advance
Andy

[Tony McC]

You will still need a sub-base, but its function will be to regulate the uneven granite surface, and thereby ensure an even, regular depth of laying course material, rather than to provide a strong, load-bearing layer.

[lemsip1]

Thanks for your responce to this.

I mentioned before about carpet stones which I have now been able to source a little cheaper and am again considering.

Are they a good option for a sloping driveway? Are they any good at all?

thanks again for your help.

Andy

[bobhughes]

I don't think I would want to grout 125m of carpet stone.

Have a look here

Bob

[Tony McC]

I can't recommend Carpet Stones for a driveway, and as far as I can recall, even the manufacturers won't recommend them for vehicular use. The problem is the concrete used to manufacture them: it's a wet-cast grade concrete and therefore not as durable as a pressed concrete.

Of course, you could say "soddem" and ignore this advice, as it is your own driveway, and it's not as though they would fall apart as soon as you parked up on them, but they would abrade and you'd have no chance of a claim against either the supplier or the manufacturer. On a flat driveway, I'd suggest you weigh-up your options, but with this being a driveway with a significant slope, I feel bound to caution you against using them. The extra traction required on a gradient will accelerate the surface abrasion, and there's a risk of the concrete polishing, making it relatively slippy. Think carefully before committing yourself.

[lemsip1]

Thanks again all

While the Bradstone website does state they are for driveways. I totally appreciate what you are saying and take your advice fully. "soddem" does not seem to be a good option except to give me a problem. I will not be committing myself to them. A better option is to be found.

After reading both comments above and the referred to topic its interesting to read on the Bradstone web site "ingenious solution for building pathways, driveways or patios without the time and expense of laying individual stones"

It appears the laying is "easy" compared to the grouting.

Thanks for all the comments and advice.

Andy

[Tony McC]

Somewhere in the Bradstone tech literature, it definitely states CS aren't suitable for driveways with the exception of one format, which, from memory, is the 'random' jobby....hang on while I get the manual....naah, I can't find it, but I do recall a discussion with the marketing manager and the products manager for Bradstone when they first started to really push the CSs, and they both told me CS were not really suitable for driveways, and the reason was the straight-line arrangement. I have a record of the conversation somewhere...probably in with the Bradstone tech manual!