Rocking blocks! - ?jointing sand problem

[sampsonr]

I have just had a 260m2 driveway laid with plaspave carrera blocks.

Within days around 25% of the blocks are showing movement (rock when stood on), and are throwing out the jointing sand. The driveway was laid 4 weeks ago, during which the temp dropped below freezing, with snow for several days. Also, I noticed that the contractor used jointing sand (kiln dried sand) which was damp, and the blocks were also damp when compacting after sweeping the sand. The contractor says that he is mystified by the rocking blocks, but that the jointing sand should not be the problem as it is purely decorative, and the blocks are stabilised after wacking by the base sand which creeps up the joint. I think this is rubbish and shows a basic misunderstanding of the inportance of dry sand filling the spaces to lock the blocks.

He has offered to redo the laying but I am concerned that the problem will recur if it is not properly jointed?

Is the damp sand, with many unfilled joints, the cause of the problem?

By the way, he has already had to redo the edges, which sank under my campervan, as he had no concrete base under the small edge blocks! Your site has been very helpful in enabling me to educate a 'professional'

Thanks

Ralph Sampson

[Tony McC]

If this clown thinks the jointing sand is purely decorative, he ought to go back to his normal job, because a professional pavior he isn't! And to claim that the bedding sand 'creeps up the joint' is complete and utter bollocks - it may do so for a millimetre or two, but if it was 'creeping' any more than that, it indicates there's a serious problem with either the bedding, the blocks, or both.

Those joints should be full to the top, and with no rocking at all. If the blocks rock, it makes me wonder if there's a problem with the bedding sand. Did you see this when the paving was laid? Did you see how it was laid and screeded? Could you lift out a block and examine the bedding beneath?

[Paverman Dan]

Egads, while yer at it, if this yahoo is telling you that jointing sand is "decorative", I'd also have a gander at how much, if any, base material he used. Your comment about the edge blocks makes me suspicious.

If your driving a campervan over the pavement (we call it a motorhome here in the Colonies) I want to see 8-12" of base, properly compacted to 95%-98% Proctor density, on top of 500x geotextile, or no matter the freeze thaw, your gonna pop out some pavers.

Moisture in the bedding sand, if it was in there during the freezing, would also be a contributing factor (see . . water freezes then expands . . causing movement in the sand . . . eeeh, we all know that) . The pavement and sand should be covered with a tarp to prevent moisture from interfering with the installation process. If the sand or pavers are wet upon jobsite delivery, both must be dried out.

Tony, any way we can fly this contractor into DC for an ICPI thrashing? LOL



Edited By Paverman Dan on 1103514143

[Tony McC]

Sod flying him to DC, we can give him a good thrashing in Wigan on a wet Wednesday! :laugh: