I'm currently collecting opinion on the best way to lay some paving slabs on an old flower bed. The slabs are going to be the location for a wooden playhouse for the kids.
So far I've had a 50/50 split on whether to use just sand, or a sand and mortar mix. How thick?
Weed membrane under the sand?
Grout the joints with wet mortar, dry mix or just sand?
Never done it before, anyone got any good tips please?
get a man in, and go riding while he does it......... 
If you get the sand layer well compacted you shouldn't need any mortar. Weed membrane sounds like a good idea although the weeds will eventually get hold in the sand too. I certainly wouldn't mortar the joints, just butt the slabs up tight. As for sand depth, the builders who laid slabs around my house used 3 to 4 inches, seems to have worked fairly well although they are big slabs.
What stumpyjon said but deffo put a membrane down with 75mm blinding on top
75mm blinding? (sorry!)
I recently laid a base for my kids playhouse. I managed to pick up a load of split bags of Blue Circle Slab Layer for about 50p each from Wickes which was ideal, and nice and easy. I then just put the biggest, cheapest slabs I could find on top of that.
No need for a membrane as weeds won't grow in the dark under the playhouse.
When you finish, brush a sand/cement mix into the joints - then use a watering can to soak the joints. Then let dry.
if your putting a playhouse on top, you shouldn't need the mortar mix. but do spend the time to compact the sand and the soil underneath the sand and get the levels right, putting it right after building the kids playhouse may put you in the doghouse!
Stick a bag of cement (or 2) in with the sand and lay a dry mix. Its not much more effort but will harden things up a bit for only a few quid more. Cement will go off with the moisture in the sand. I'd just get some sand down and then sprinkle cement into it and give it a bit of a mix on a slab by slab basis. Not like you're parking cars on it or point loading the slabs.
75mm to 100mm thick sand layer will be plenty.
You can brush dry cement dust into the cracks too as I've found this keeps things from growing through much. Wash the remainder away with plenty of water.
Hi, i build patios and pathd, shed bases for a living and my advice is if you want it to last dont cut corners and lay the slabs on a wet mortar bed and point up. The pointing has to be troweled in so that it is tight.
If you just lay the slabs on a sand bed and dry sweep the joints it will not last at all.Just look at all the websites on path and patio laying and the will say the same.
Its a bloody nightmare, getting it level and not wobbly will take years off your life.
well that puts the cat amongst the pigeons! cheers nosher for making my life harder
can you point me at a website that you think gives a good step by step guide please? as i said, i've not done this sort of thing before!
Just type in laying a shed base and i think there is a site from Mcormick paving suppliers that is good.
You say that kosher but my next door neighbour is in the same trade. He's laid his new forecourt on sand with brushed mortar and has now got cars on it. He also did the rear of mine 15years ago. It was covered in earth for 5 of those before I moved in and exposed it. It's as flat as the day it was laid. It has concrete haunching ti the edges to keep it all mice and tight. If the sand isn't compacted enough then it won't last but all my site especially where pedestrianised are on a sand blinding
Yes but i expect the forcourt is block paving, and not slabs which is a different ball game altogether.
Paving Expert is your friend.
dig the soil out, lay 100mm of hardcore, wacker it down then lay slabs on 5 spots of 5:1 mortar mix, point up with same mix.
Dig out >100mm, layer of geotextile, layer of compacted type 1 hardcore, layer of dryish mix, take the time to level them, then point it up properly.
5 dabs of mortar wont work if your slabs are all different thickenesses i dont think,
fancy stone slabs?
or cast concrete ones? (should be fine with them)
Surely life is too short to go to all that effort above ^^^^ for the sake of a childrens playhouse? I'd just dig out to the depth of the slabs plus a bit and level it out, compact the soil, level with sand and lay the slabs over the top butted up really tight. Once done the and playhouse on top what is going to go wrong?
This has worked fine for me in the past and for small sheds and the like its perfectly adequate IMHO.
Before you decide what method your going to use think about what you will do with the area once the kids have grown out of the playhouse. Will you want something easy to get up or will you use it as a patio or put a shed on it?
This hasn't really sorted much out really, has it? 
End of the day I'm a bit of a lazy sod, so probably sand (maybe with abit of cement mixed in if I'm feeling flush in Jewsons) base, with the slabs tight together...
If I have ignored your advice then I apologise! I'm sure your method would be just fine...and if it goes tits up I'll let you all know.
Did my patio last year. 750mm MOT Type 1 compacted in 50mm layers, 50mm sharp sand compacted in 10:1 dry mortar mix, 35mm slabs. You could stand a crane on it.
750mm of type 1!! they don't even use that much under motorways!
750mm! How big is the patio? Did you compact it with one of fred dibners rollers?
dig deep and use a bag of lime to help break up the corpse.
Oh erm.......
Meh, we had play house - put it on stilts and then on a paving slab under each corner.
We did this and it's great - easy to spray off underneath and keeps bugs out.
But then we're in Australia, where even the moths are toxic...
+1 paving expert
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