The Brew Cabin

Posted: **Thu Aug 09, 2012 3:20 pm**

Hi all experts,

topped up my sub-base last weekend and that worked out very well

Thanks again for those helpful tips.

So, this weekend I am laying the paving blocks. My blocks are 80mm thick (that's right I live in Germany and that's considered a minimum here!)

I will use the compaction first and then screed method. My laying bed of sharp sand will be 40mm after compaction. Also the paving block manufacturer recommends using the neoprene blanket with these concrete blocks as the finish is textured.

The problem is that I have one long edge as soldier course set in concrete and haunched. Now I am getting concerned that according to the table 1 http://www.pavingexpert.com/screed_faq01.htm

the blocks will have a 8-10mm surcharge before compacting. That seems like quite a lot. When I read through other similar questions on this forum 5-7mm seems to be quoted as the way to go. But, it's difficult to ignore TMcC.

Of course I know there are many variables and no golden rule. But I don't really have time to run experiments. We can't make noise here on a Sunday and I want to complete the laying on Saturday while I have some helping hands.

Look forward to any opinions.

Nigel ???

Posted: **Thu Aug 09, 2012 6:32 pm**

I would screed it, compact the lot then re-screed it. Leave 3mm above your edgings. Spot on, wont move

Posted: **Thu Aug 09, 2012 6:44 pm**

i find that if the sand is wacked before it is screeded 5mm is absolute spot on
better to have them 1 mm proud than 1 mm dropped
LLL
ps better spot on of course

Posted: **Thu Aug 09, 2012 7:09 pm**

Actually yeah i will bow to that advice. Go 4.25mm

Posted: **Thu Aug 09, 2012 8:34 pm**

as above^^^ 80mm blocks need a good sized whacker to compact 10mm in a 40mm pre compacted bedding layer 5mm sounds good, a small dusting or sprinkle of sand under your edge cuts will give you a bit of tollerance in compaction and try to keep some of the plate over your edges at all times so as not to go to low with the whacker post some pics of the blocks plz

Posted: **Thu Aug 09, 2012 9:14 pm**

Thanks to all for the quick reply and good advice. 5mm it is then. I will sleep better tonight

I will post a photo of the blocks tomorrow. The neighbours already think I am crazy without taking photos of paving blocks in the dark

Cheers, Nigel.

Posted: **Thu Aug 09, 2012 9:19 pm**

Oh! BTW just to complete the whole picture the whacker I am renting is 16 kN/80 kg.

Nigel

The Brew Cabin

Screed depth - Just need my hand held