Laying patio - Marshall's Heritage range, how to?

[Mike Dodd]

Hi

I've been reading various online guides for laying patios, and after dragging 'er indoors around a couple of builders merchants have decided that I'd like to try my hand at laying a garden patio - around 25m^2 of Marshall's "Heritage" flags (cast concrete, 30mm thick, typical

300/450/600mm grid).

Now, The

guys typically recommend bedding patio flags on a 50mm compacted sand (1:10 mix cement:sand, to improve the stability), however, also mention bedding on a semi-wet mix (a sand/cement mix where the water is drawn from the damp sand) for riven stone and thin flags.

Marshall's, however, (who I have to consider an authority on their own flags) suggest a wet bed - presumably this means the concrete that I've always seem my own father laying - with the consistancy of cold custard (sorry).

Can anyone explain the rationale behind the various methods, and why Marshall's recommend a method that pavingexperts don't deal with (hey, they were the first website I found with details - digested them all, then found non were applicable to the flags we've decided upon).

Any helpful suggestions gratefully received (or failing that, any suggestions how to dig up 3 ton of concrete if i get it wrong, also gratefully received).

Regards

[Pete C]

Hi,

Maybe the Marshalls recommendation is for a drive, which would need to withstand higher loadings.

cheers, Pete.

[MBQ]

I'm going through a similar process myself and I get the impression that the compacted bed method is appropriate for flags that have a consistent thickness.

Some flags vary in thickness due to the way they are made and then the wet bed method is appropriate allowing you to level each flag individually to compensate for thicker/thinner flags. Otherwise you end up with an uneven surface.

MBQ

[Colin Brook]

In message on Sat,

15 May 2004, Mike Dodd wrote

Over on the uk.rec.gardening group, any question like this tends to get referred to this web-site:

which I've certainly found to be most helpful. I think there's a good chance you'll find authoritative answers there. Regards, Colin

[John Forbes]

This is how I and my chum did it this w/end, 20m2 Marshall's heritage of the type you describe patio for light pedestrain use:

1) dig out topsoil down to clinker/clay 2) put in level pegs, allowing 4-5" at high point 3) backfill the low spots with some of the topsoil and tamp down firmly (i used sledgehammer as a rammer) 4) semi-permeable membrane down (cutting holes for level pegs, obviously) 5) 2" of sharp sand for drainage, spread as level as poss with rake 6) approx 1" of builders sand, spread as level as poss with rake 7) set string lines for edges of the slabs 8) final thin levelling layer using dry mix 1:5 cement/ builders sand one slab at a time 9) slabs down one at a time,

[Tim Nicholson]

[Mike Dodd]

To all on the group - thanks for your advice. This, coupled with a forum reply on pavingexperts leads me to think of trying the dry/semi dry mix.

With particular reference to John. 1st - a "Chum", ah, call em "mates" up north, lad; Hmmm, may need to invest in one of them. Regarding the Fosters, hmmm, sounds half-hearted (wonders if the builders merchants can deliver a crate of Guinness).

Many thanks, all.

Mike.

[John Forbes]

This was one of those jobs where my chum/mate was the one who knew what he was doing and I was the labourer. Adding to what I'd said earlier, three important general points:

1) taking proper time to level each slab is absolutely critical if you want to do a good job. It's not enough to bung them down and jump up and down on them a few times; if they rock, or are not level, then raise up cautiously so as not to disturb the sand underneath too much. Then it's a bit of a black art shaving off a bit of sand at the high spots or trowelling it a bit extra at the low spots (as indicated by the un-compacted sand underneath, if you see what I mean). We took anything up to 10 minutes per slab doing this but were probably being over-meticulous. 2) getting rid of the waste you dig out - have your strategy for this planned before you start!! 3) I initially tried to cut these Marshalls slabs with a small grinder and a stone cutting disc to score 1cm deep then a brick bolster. This failed; underneath the thin decorative top layer there's a very sturdy concrete with a lot of coarse aggregate, which won't crack obligingly in a straight line. I'd suggest you borrow or hire a big grinder (and remember your goggles and dust mask).

John

[Mike Dodd]

Hmmm, yeah, thought about this - don't like the "black-art" side of things, but I can afford the time to get it right.

2 ton skip upgraded to 4 ton skip prior to delivery on Saturday. 80% of garden dug over already - will finish off when skip arrive. Wheelbarrow greased and ready for action.

Ah, duely noted. Will consider laying out the slabs on paper first, to minimise on cutting. I've got a good degree of freedom as to placement (i.e. the borders can be encroached).

Many thanks (and seriously, Fosters?)