Block paving over concrete

[mickg]

*sigh* ok ok your right again :p

It was only from a comment passed by our leader last year when I met him for the first time and we was talking about the different ways to install block paving and he as the forum owner can't post anything what could lead to putting himself at risk for any possible come back, I was only following that same path

I have installed lots of driveway lately on 150mm concrete due to the ground being very soft and spongy, rather than keep digging deeper pour concrete to stablise the ground and lay the blocks on a semi dry mix instead of the sand laying course

I must add its not the conventional way to install block paving but when you have dug 300mm off a driveway and your a spade depth still into soft ground its the only way forward

happy now sean

[seanandruby]

He, he. Always happy mick, just a curious bugger. I like detail and you are good at that, that's why i ask you questions. I hold you in the highest regard. Thank you for your patience

[David 1234]

Thanks Sean and Mick. So what is the concensus - to put a flexible pavement on top of the rigid base using drainage in the form of 50mm plugs taken out and filled with type 1 or go with mortar? I hear what you say about having to put cement in the mix to make it rigid but surely that would defeat the object of the holes.

I've had a contractor look at the job and he said that he has a machine with an attachment which can extract the concrete in the form of plugs qnd that this would make it perfectly ok to lay on sand.

One thing that I didn't understand - he said that he's laid rigid pavements before and screeded a section then whackered it. Surely a compactor plate would make a mess of a driveway laid on mortar? I'd always imagined that a driveway on mortar would be a bit like building a wall with each paviour individually set in place but the contractor said that it would be too labour intensive.

[mickg]

yes your correct, if you add cement to the sand then you do not need to bore the holes as you will have a rigid driveway

what your contractor means is he has mixed a semi dry mix and placed this mixture over the entire area to be block paved, either lightly compacted the mix with the back of the spade or steel float

then screed this mixture to the correct level and fall and lay the block paving on top, complete all the cuts and add the kiln dried sand to the joints and then the final compaction with the vibrating plate on top of the block paving to bed everything into place

because its a semi dry mixture the vibrating plate will not make a mess, if the mixture is too wet then thats a different ball game and can easily end up looking like a pig ear but it sounds like your contractor knows what he is talking about so let us pray this does not occur ???

unless its a large driveway I would normally screed the total area in one rather than break it into smaller areas but everyone operates in different ways but still end up with the same result

there are reason for having a rigid driveway, if your parking a medium to large van or a 4 x 4 SUV on the block paving then I would certainly recommend constructing the driveway as the rigid method rather than flexible

your reason is different because it will save removing the existing concrete

don't forget you need to add drainage to conform to the planning legislation
front garden paving

[David 1234]

Thanks Mick. I'd imagine that the driveway will only accomodate an ordinary car. I'm honestly scared about the rigid method because even the most experienced people on the forum talk about the potential for staining - Mr McCormack himself on the page about rigid paving talks about the need for an acid wash a coulple of weeks after laying as it's almost impossible to do it clean.

So I'm trying to avoid the rigid method where possible but what I'm not sure about is whether Mick and Giles's MOT in cut out holes method is universally accepted - Sean doesn't seem too be too keen on the idea and the last thing I want is a disaster.

[mickg]

yes it is an accepted method to drill the holes and fill with MOT, phone Marshall's technical helpline and they will confirm it
0845 820 5000

if your contractor puts plywood sheets in the area's where they will be walking then the staining is kept to a minimum without having cement footprints all over the place, that how i do it and i have never had to remove cement stains with acid on any of the work I do but that said I keep everything very clean anyway

this driveway i did 3 weeks ago was laid on a semi dry mix and there is no staining what so ever


grrrr see what can of worms you have opened now sean :p

[GB_Groundworks]

I love the neatness of your block work mickg top notch as always

[mickg]

thank you Giles

[David 1234]

That driveway is utterly stunning. Since looking at getting my driveway done I've started noticing driveways in my neighbourhood - it's amazing how few actually get it right.

One thing with your method of rigid paving - you spoke about using kiln dried sand and wacking it in. The site talks about using mortar for jointing and suggests that this is what makes staining so likely http://www.pavingexpert.com/rigidbpv.htm

[mickg]

this driveway was laid with a semi dry mix and the blocks bedded into place using a lump hammer and a 3 ft length of 3 x 2 timber as I could not use the vibrating plate on this type of detail but with a lot of care a attention you don't get any cement staining

[David 1234]

I notice that in the circle you don't have wider joints in a kind of a v, bu instead have cut each paviour to make a true fan shape. This is the kind of thing which I just haven't seen around here.
You may remember me and now realise why I am so paranoid - I along with you had trouble with Stonemarket Arctic granite staining - what a nightmare that was, had to have two patios ripped up and a big fight to get reimbursed. Anyway is kiln dried a decent method as mortar jointing on a rigid pavement? I just want to avoid problems as if it happens to anyone it'll happen to me - the guys who put in my patio reckon I'm jinxed.

[mickg]

what Tony is describing on that link is buttering each block together and having a mortar bed too like what you would do when laying bricks to build a wall but instead the paving block are lay flat, then you would joint them the same as you would do with brickwork

that would be a very time consuming process to construct on a driveway, that page is also a few years old and in between time they have brought out other methods of jointing paving which would be faster than the method described

what I am suggesting is instead of using the sand laying course you are using a 4:1 semi dry mixture but your laying the block paving tight together the same way you would lay them if it was on the sand laying course so therefore you need the kiln dried sand to fill the 1-2mm joints

its an unconventional method of laying block paving but I have used it for many years in certain circumstances when i feel its required to give a more stable finish to a sub base

[mickg]

I do recall you now David, my customer got her money back and compensation too, how did you get on ?

[David 1234]

I get it. Do I take it that the kiln dried sand in the joints behaves the same way as in a flexible pavement and so if I powerwash I'll need to sweep more in?

Did you ever get anywhere with Stonemarket with that granite patio?

[mickg]

yes you would have to keep the sand topped up in the joint just the same as you would do with the conventional way of laying block paving

yeah I posted a reply before yours