Starting first time - Whacker plate

[cucci1968]

hi tony /all, i am now starting to block pave for first time,onto existing concrete,i have drilled 22mm holes, as you suggested,
first question, do i need to fill these holes with gravel?
2nd question, when i whacker the blocks to its final level,
how much an area should i lay for a trial run, and do i put sand into the blocks when i do this? as you say it is trial and error to find the compaction rate of the sand,as so you can whacker it to the correct edge course level.( I didnt want to lay too much and then find that i had to take it all up again) 3rd question ,i know that i whacker the blocks until that edge course level is met? but is there a max you can go over with a whacker plate? thankyou, much appreciated,regards tony.

[Tony McC]

Q1 - fill with pea gravel, grit or grit sand and cover with a permeable geotextile such as Terram.

Q2 - A couple of quare metres will be planty, and there's no need to sand the joints at this stage - wait until you consolidate the completed pavement.

Q3 - You can't over-consolidate. You reach a point known as "compaction to refusal" which is the point at which the blocks will simply not go down any further and the vib. plate starts to 'bounce' on the surface. When/if this happens, stop immediately, as there is a real risk the bouncing vib. plate could damage the blocks.



Edited By Tony McC on 1143991243

[cucci1968]

hi again tony, i have now completed my edge courses, following your advice,and i am very pleased with them and they look spot on.i just need to clarify a few things if thats ok. i will be starting to put the base in (sharp sand) and blocking next week,when this is completed i.e. ive screeded the base and put the blocks down, some people advise,to compact first before putting in the kiln dried jointing sand, then put the jointing sand in and recompact, is this correct,or do i put jointing sand in and then compact to finished level?
2nd question, if it chooks it down, (rain) and the sand gets wet, can you still carry on with compacting the sand? If the sand is already compacted and ready for laying blocks can i still lay the blocks and compact whilst wet, or should i wait to let the sand dry?
3rd question, on concrete is it ok if the sharp sand base is only 20mm thick? thnx tony much appreciate your response, regards tony

[Tony McC]

1 - doesn't matter. My preferred method is stated on the main website: brush-in the sand; sweep off the excess; consolidate with the plate compactor; top-up the sand

2 - If you've used the correct type of sand, it should drain very quickly and be suitable for work to continue within 15-20 minutes of the rain stopping. If heavy rain has disturbed the prepared laying course, then you ought to re-screed.

3 - 20mm of layiung course over a concrete base is going to take a high degree of accuracy to achieve the correct levelk following consolidation. It's less than ideal (30-40mm) but it's not totally naughty.