The Brew Cabin

I have had the front of my drive Block Paved exactly a year ago. the problem I have is small and large holes have started to appear on about half of the paving and look like they are getting worse. Should this be natural in such a short space of time? i have contacted the builder who has done the work and he seems to blame the brick manufacturers and doesn't seem bothered at all. i have spent good money on something which i hoped would last me for years but is turning into a nightmare. Would resiblock 22 at least slow this process down or would they need replacing. Photo's available.

As mentioned when I replied to your email on this matter, I cannot comment until I see the photos.

Hi Tony

Sorry but the pics might be a bit big to post please have a look at:

http://emspace.homestead.com/pavingpix.html

Many Thanks

These look like Marshalls blocks, and the 'holes' are typical, I'm afraid, not just for Marshalls, but for most of the large manufacturers. They happen because of incomplete compaction of the semi-dry concrete mix when it's placed in the moulds. They don't appear at first becaus ethere is often a thin 'film' of concrete nmasking them, buit, as the pavement is trafficked and weathered, the 'film' disappears and the holes become evident.

I've noticed that this phenomenon is more prevalent with multi-coloured blocks, that is, blocks containing two or more differently coloured concretes. I did wonder whether the hydraulic press that is used to compact the different concretes into the mould during manufacturing was set to a lower level of compaction or perhaps not vibrated, but none of the UK manufacturers are all that keen on revealing their exact manufacturing process, so my suspicion remains. Most of the block manufacturing plants I've toured, both in the Uk and in Europe, all have vibrating presses, but the degree of vibration and compaction is not revealed.

However, the point is that these 'holes' are commonplace with that type of concrete block paver and the manufacturer will probably not entertain any claim for sub-standard materials. Still, your contractor really should be prepared to ask the manufacturer to send out a Rep so that your questions can be answered. It's not as though it costs the contractor anything, and it would come across as good PR. If there were a substantial number of the holey blocks on your pavement, 30% or more at a guess, then the manufacturer might be sympathetic, but would be quite right in pointing out that the contractor shouldn't have laid the blocks if there were so many sub-standard units.

If you want to use sealant, wait until you know whether you are going to get a vist from a Rep. If you seal the blocks before they've been inspected, you could invalidate any claim.

Applying a sealant will not eliminate these holes: they'll still be there after the sealant is applied, but the sealant will help to keep the pavement cleaner.

I would go back to the contractor, ask them to arrange for a Rep to visit the site and take a look at the blocks, and then take it from there, but I don't want to build up your expectations. I really don't think you're going to get the blocks replaced, unless, as I say, there are hell of a lot of them on the pavement, and the Rep is in a particularly generous mood.

Hi Tony

Thank you for your honest answer. my builder also stated the best thing to do would be to get a rep down and inspect. as for the amount block paved try 96x96 m2, which is a lot, which is why it is frustarting me so much. Do u think the holes will get any worse and approximately how long should the block paving last looking at the sort of condition it is in using the resiblock 22?

96 x 96m!!! 9216m²!!! That's a lot of paving, Tony!

As the blocks are now 12 months old, I don't think they'll get much worse. Obviously, some blocks will continue to develop more 'holes', but I would imagine that the vast majority of the holey blocks have made their presence known by now. Still, I;d definitely get the Rep down, though - 9000m² is not your average domestic driveway!

Even with the 'holes', your block paving should give you at least 20 years of service, possibly even longer. Some of the earliest block paving we did is now 22 years old and is still serviceable as a pavement, even if it is a bit grotty and could do with a damned good cleaning. I'm not sure that applying a sealant would dramatically extend the lifespan of your paving, although there is some research from studies on heavy duty block pavements (such as airports and freight yards) which shows that using a quality sealant does indeed reduce maintenance requirements and, so, extends the working life of such pavements.

Thanks Tony

One final thing if the worse came to the worst, and I paid to have them replaced with the same type of brick and colour and then sealed them straight away, would it make a difference?

I really wouldn't bother replacing them, Tony. In all honesty, we see 'faults' on our own driveways and patios that friends and neighbours would never see unless they were pointed out to them, but that's because we spend more time looking at said pavements. I know the photies you've posted aren't the most attractive, but, looking at the bigger picture, I'll bet very few of your visitors have even noticed! They see the whole pavement rather than individual blocks.

Replacing the lot is no guarantee that the new batch of blocks will all be what we call 'tight', ie, no holey bits on the surface, and sealing any concrete block pavement immediately after laying is never a good idea. The blocks need time to 'settle in', for the jointing sand to be topped up (usually 4-8 weeks after laying) for any efflorescence to work its way out, for any settlement problems to come to light - I always recommend leaving a new driveway/patio at least 3 months before applying a sealant, but I know some folk are quite happy to seal them immediately.

Have you got a photie of the driveway as a whole? The Brew Cabin Irregulars could all take a look and vote on whether they'd bother replacing it - wodjer fink?