The Brew Cabin

I am in the throws of extending an existing driveway and after as many tips as possible to the point of having conflicting ideas.
Sub base is down and compacted, soldiers set on croncrete all way round area and I understand from this site the best way is to screed sand layer proud, lay blocks then compact down to final height with a wacker, however today a local expert tells me the sand must be compacted to the final level before laying blocks or they will subside. Is this right?
Also am I wasting my time trying to complete this in the rain as weekends are the only time I have along with the hired wacker / cutter etc..

Hi Ros,

your local expert is wrong, I'm afraid. It is a requirement of all block paving that the blocks themselves are consolidated into the bedding. Part of the reason for this is to accommodate the slight variations in thickness that occur with all blocks. If the bedding layer is solid, with no give, then the blocks will remain higgledy-piggledy.

BS7533 Part 3 gives 3 possible ways of screeding in preparation for laying blocks, and the method we find to be most successful is that described on the block laying pages of this site, namely, level sand out generously, lightly compact with 2-3 passes of plate, screed to level+6-9mm, lay blocks, then consolidate blocks down to final level. We find this method results in fewer incidents of settlement than any other.

There's nowt to stop you working in the rain, but heavy raion should be avoided, as it messes up the bedding layer. Also, you can't do the dry sand jointing in the rain - obviously. Light rain or drizzle is not normally a problem, unless it's in for the day, as we say, and then it does more damage to your spirits than it does to the actual paving!

Thanks for that Tony.
Can you give any tips on how to best match the new drive into the existing. I have bought the same brand blocks as are already laid but they have been down for some years and there is an obvious difference in colour. Pressure washing has done little to return their colour and I don't really want to pick up too much of the existing drive if I can help.

There's nothing you can really do to make the new blocks match the old stuff. Concrete mixes vary over the years; the dyes change, and the blocks become weathered, which just cannot be replicated under normal circumstances.

However, in 12-18 months, the new will have mellowed and, if you power wash the lot then, there should be less of a difference.

On projects where the new absolutely must blend in with the old, then the only viable solution is to lift some or all of the old and mix them in with the new before relaying. This gives a very mottled appearance at first, but it begins to blend in within a couple of months.