What's the construction of the existing driveway?

I suggested direct bedding to the previous query because it is such a relatively small area - not much more than an extra soldier course, but for larger areas, I have to agree with Marshalls and say the blocks really should be laid on a sand bed over a suitable base or sub-base. You could lay the blocks on sand over the existing concrete (see the Laying over an Existing Base page) if the situation is suitable, which would do away with the problem of breaking up all that concrete, but have a read of that page first, and see if it's possible.

I can now see that laying over the existing concrete base is not the right way so I will be hiring a breaker and skip for a few days!

The only word of advice I'd offer is that you make sure the bond runs transversely (pavior-speak for the bricks to run across the drive rather than 'up and down', which is referred to as longitudinal). Laying transversely is more pleasing to the eye, is structurally stonger, and has the added benefit of hiding any slight pattern creep for casual passers-by.

I'd hazard an educated guess and say that flexible bedding is the way to go with your project.

How you choose to lay the additional circles is up to you. The first couple of courses may need some trimming to keep joints widths reasonable, but after that, the full blocks usually fit quite well.

Here's an image of your options....

...if you intend using the same colour, then laying the additional courses lengthways (as on the left hand side of the image) looks better to my eye, but if you plan to change colour, then laying the blocks widthways can help emphasise the change.

So, if a block pavement has a kerb, that can be concreted-in and used as the restraining edge, or, as is the case with your drive, the edge blocks should be concreted-in.

....where the wall is rebated (stepped back) to accommodate the doorway, the soldier course should follow the brickwork, as shown in the right-hand image above, rather than be 'infilled' behind the soldier course, as shown in the left-hand image.

Is that what you meant?

For the transition between the driveway and the public footpath, your idea to use a kerb unit to form a short ramp is fine, or you could scrape away at the sub-base to create just enough depth to accommodate the new paving and a minimal bed of 30mm of sand. Personally, I like the idea of using the kerb units, and then, if you're still struggling for depth, use an extra-wide border course, perhaps even building in a pattern such as....

...just at the transition will help overcome the level difference.

Once you've removed the bitmac, and skimmed-off as required to accommodate the paving at key points, you need to 're-grade' the sub-base, which simply means checking it all for level, skimming off any high spots and filling in any low spots or hollows with DTp1, and then compacting it all again. Although much of it will be firm and solid, the tarmac removal and subsequent tittivating will have loosened the sub-base in places, so it's best to reconsolidate the lot in one operation rather than do bits here and there.

Are you ok with your dpc levels?

Anyway, Classico Blocks are fine and the Classico chippings are fine, too, if a little overpriced. For that reason, many installations of Classico disregard the chippings completely and use all sand joints with no apparent loss of pavement performance.

From a workload point of view, I'd guess that laying the blocks on, say 50-75mm (2-3 of your old-fashioned inches) of concrete, is actually less work than excavating for, laying and compacting a sub-base of 100mm and then repeating the process with the sand bedding.

Clay pavers are often considered to be more brittle than their concrete cousins, and so many contractors choose to use the rubber mat when consolidating, but it's not always necessary - as Suki says, a good, generous covering of the jointing sand can provide a sufficient degree of cushioning, and the only real danger of spalling clay pavers is when, because of the slight deformations that are inherent with any kiln-fired product, two adjacent bricks are in direct contact, and so rattle against each other. Because concrete pavers have a high level of dimensional accuracy (usually), the odds on two pavers being in direct contact is much less, and so spalling is less likely.

But, if you want to err on the side of caution, then you should fit the rubber mat before final consolidation.

I'm with Suki, too - we would never issue a guarantee with block paving unless we had installed the sub-base ourselves. I'm happy enough for someone else to have done the excavation, but, from that point onwards, I preferred all the construction work to be checked and approved by ourselves.

Splitting the job has got to be more costly than using a single contractor. You have two, three or more gangs, each looking to make a decent profit on what would be a relatively small job, instead of a single contractor making a fair profit on a reasonably sized job.

Regarding materials quantities and drainage issues, all of these are covered in excruciating detail on the main site - have aread through all of that before committing yourself to what could be a very long and very costly methodology.

I'm having the drive excavated on Friday, with a grab to take the load away.

Suki - I live in Luton. Without seeing the job, what would be your approx cost per sqm having completed the dig?

2 - 50mm will be fine, 60mm would be better, but it really doesn't matter for a residential driveway.

3 - 50mm is the maximum recommended thickness after compaction. Read the Screeding page for a fuller explanation.

4 - see above. I recommend the pre-compaction method, as it gives the best results in the longer term.

Good luck and let us know how you get on!

It's best to lay the edge courses on a semi-dry mix of concrete, as described on the main site. There's adequate moisture in the sands and gravels to initiate curing of the cement, so no need to add extra water by hose, by bucket or by any other means. You can use a wetter mix for the haunching, but a semi-dry mix is ideal for bedding.

Weeds - other than the really pernicious, nuclear-bomb proof weeds such as Japanese Knot Weed and Equisetum, the vast majority of weeds will not grow through a properly constructed block pavement. There's 200mm of heavily compacted, weed-unfriendly material between the sub-grade and the surface, and your average dandelion or daisy does not stand a chance of getting through that lot, whether there's a weed membrane there or not.

However, weeds will settle onto the surface of the completed pavement and grow into the joints, and no weed membrane can stop that, regardless of where it's positioned.

So, a weed membrane is not necessary beneath a properly constructed block pavement, and to use a sheet of polythene rather than a proper permeable membrane is a certain recipe for disaster. I don't know who's giving you all this duff information, but maybe you should start drinking in a different pub, because the expert you have there is a right numpty!

The use of membranes beneath block pavements is covered elsewhere on the website, but their purpose is to add stability to the construction, not to prevent weeds. Weed membranes are fine benath mulches and other loose surface dressings, but they are a complete and utter waste of time and money beneath a properly paved surface.

With any form of paving, you always start to lay at the bottom of a slope and work your way uphill. If you do it t'other road round, the paving starts to slips away from you as you lay it!  

There's a 3mm joint between the blocks, so you need to allow for that. However, assuming that each joint will be exactly 3mm is fatal, as the figure of 3mm is an ideal, and, in real life, the joint will more than likely be somewhere in the range 2-5mm. So, if you laid 26 courses of block paving, you could end up with a width of between (26 × 102mm) 2.65m and (26 × 105mm) 2.73m, a range of 80mm.

If you want to be sure of using as few cut blocks as possible, then the only way to work is as follows....

1 - lay one edge course on concrete bed and then haunch the blocks so they are firmly held in place (unless they are up against a firm fixture, such as a wall). This is your fixed edge course.

2 - lay the opposite edge course on semi-dry concrete bedding, with ample spread of the bedding to the outside edge of the blocks. Lay these blocks at the minimum theoretical separation from the fixed edge course (2.65m, as calculated above). This is your free edge course.

3 - prepare your screed and lay the blocks as per normal instructions. This is the body of the paving.

4 - adjust the position of the free edge course blocks so that they give a tight joint against the full blocks of the body paving. The edge course blocks can move out on the generously wide bed you prepared for them in step 2 above. Just slide them over carefully, so that the level is not affected, just the alignment.
Once all of the edge course blocks have been moved as required you should check the alignment with a taut string line, as there will be some deviation, and, if you rely solely on creating a tight joint between the blocks of the body and those of the free edge course, it will look like a crippled dog's back leg. You will have to do a bit of 'give and take' with some joints being a touch wider than other so that the edge course looks straight.

5 - Once you're happy with the alignment of the free edge course, fix it in place with concrete haunching.

6 - cut in the half-blocks to complete the body paving, and then sand-up the joints. Leave the consolidation (wackering) until the following day when the freshly-placed haunching concrete will have set and will be better able to withstand the force of the vib plate.

7 - Pub!  

These Q's aren't basic - they're fundamental to the construction of a decent driveway, and the whole purpose of this forum is to answer these fundamental questions.

However, this idea of using a polythene sheet is a Class A Indicator of Dodgy Contractor Syndrome. Polythene should never, ever, ever be used beneath block paving. It is the sort of gob-shite idea put forward by eejits who think they know how to lay block paving, but really shouldn't be allowed out of the house unsupervised, because they cannot tell the diff between a sheet of polythene and a geo-membrane, and don't understand the reasoning behind the inclusion of geo-membranes in certain constructions.

Here's something from an up-coming web-page on this very subject...

....So, a weed membrane is not necessary beneath a properly constructed pavement, and the suggestion put forward by some well-intentioned but misguided bodgers that a sheet of polythene or similar can be used in placed of a permeable membrane is a certain recipe for disaster. Polythene is impermeable, which is why it is used as a damp proof membrane in buildings, but to use it beneath an elemental pavement (block paving, flags/slabs, setts, etc.) will prevent the proper drainage of the pavement layers, which will, in turn, lead to saturation of the bedding layer. With unbound bedding materials (grit sand, etc), this can have the unfortunate effect of causing the paving layer to 'float' as the bedding material begins to act like a fluid. For this reason, impermeable membranes are not to be recommended beneath block paving, patios etc, unless some other form of sub-surface drainage is present.

However, the use of permeable membranes beneath elemental pavements is becoming more popular and is a perfectly valid construction. Their manifold uses and applications are covered elsewhere on the website, but their primary purpose is to add stability to the construction, not to prevent weeds.

The above quotation is now part of a completed page looking at the use of membranes beneath block pavements.

70 quid per square metre had better include all materials and VAT. I'd definitely get at least 2 more quotes if only because the notion to use a polythene sheet beneath the paving worries the pants off me.  

If you look at any manufacturer's catalogue, they all have a clause in the small print absolving them of any responsibility for effloresence, and, to be fair, there's not a great deal thay can do about it, as it's a natural phenomenon with most concrete products, and it occurs with clay pavers, vertical masonry, concrete castings etc.

It will disappear in time. Usually, a few weeks out in the summer rain will wash them clean, but there are some cases where the efflorescence has persisted for several months. There are products that claim to shift the deposits, which they do, but they are a temporary fix, and the eff. will be back again in a couple of weeks.

As your paving is new, give it at least 3 months to see if the apparent 'staining' gets any better, disappears altogether, or becomes really 'heavy'. In around 95% of cases, it will have disappeared completely by the time we get to September.  

Yes, some water will be retained for a short period by the sand bedding, but there is only so much water that can be held in voids between the sand grains, and once they are full, any further surface water will not be able to penetrate, so it will run off over the surface. Gradually, any retained water will seep away through the sub-base, leaving only that water which is held by capillary action, which is entirely natural for a sand.

What happens over the longer terms is that 'fines' are washed into the sand bedding and thanks to gravity, they end up at this low point, where they reduce the number and volume of the tiny voids (interstitial spaces, as they are sometimes called), so even less water can be retained by the bedding sand.

There are hundreds, probably thousands, of block-paved driveways in the same situations as you describe, and they manage to survive without any additional sub-surface drainage system, so I reckon your's will be fine, Steve.  

Good Luck!

If none is evident, I'd suggest that what you have is worth hanging on to, and the best way to proceed would be to level out what's there now, lay down a decent geo-membrane such as one of the Terrams (1000 is fine) or TDP115, top that off with regulating sub-base material as required to get to formation level, compact the lot and then lay the paving of your choice.

The choice of paving will have an effect on the preparation of the sub-base. If you opt for PIC, you're going to have to bring in a specialist contractor and they should examine the sub-base to determine whether it needs tittivating or replacing, so that they can issue their standard guarantee. However, if you opt for the Drivesett paving and plan to DIY, then the decision regarding the sub-base is yours.

I can't see them introducing a wholly new BS purely for driveway blocks, so BS6717 would need to be amended, I suppose, but then, we are supposed to be moving towards a pan-European standard, and 50mm blocks are uncommon on the continent. To be honest, I don't think bringing 50mm blocks within the scope of a British or European Standard is all that important, but I'll ask around and see if anyone else is aware of this.

Turning to the issue of re-using the concrete base, laying block pavers over a concrete base is an accepted and approved methodology. If your contractor has a problem compacting blocks laid over a concrete base, it suggests their skills and experience are more limited than should be expected.

We do not use a cement-bound bedding layer beneath flexible block paving. The clue is in the title.... FLEXIBLE block paving. His method is a sort of halfway between flexible and rigid but doesn't meet the spec for either, to be honest.

Just how this botch will perform over the longer term I can't say, but I wouldn't be too optimistic. It probably will crack, but how that will affect the appearance of the blocks, I can't predict without seeing the job itself. I'm guessing you'll experience a degree of channelisation (rutting) and you may well find that some areas of the paving start to experience a greater degree of efflorescence.

I'm not sure that it's worth ripping it up and starting again, but I certainly wouldn't be buying a pint for that particular mate the next time I see him!

The problem with that method is that the edge blocks end up being laid on a bed of sand with just a trowelful of mortar or concrete slapped behind them. This is NOT strong enough to restrain the paving in the longer term. Yes, it will last until the cheque has cleared, but it's an unacceptable construction to any real professional contractor.

However, the method of laying the edge courses last is acceptable as long as the edge blocks/kerbs or whatever is being used, are bedded on and haunched with concrete, giving a properly constructed, secure restraining edge course.

As long as the finished job has the sort of construction shown on the right hand side, it doesn't matter in which order the blocks are laid, but, the problem with the "edges last" approach, is that the construction shown on the left is the usual outcome.

Have a look at the thread above about working from the middle or the edge - this includes an image I've posted showing why haunching alone is NOT sufficient to restrain a block pavement. If your man thinks haunching alone IS sufficient, then he's a cowboy, and you can tell him I said so!