Im looking to put down a small patio / hard standing in front of the shed, about 2.5m x 2.5m.
Its going to be for light use only, perhaps the occasional bit of spannering. Its not in a high traffic area, as its away from the house.
I’ve got all the slabs I need (600x600x25mm) already.
Looking at the how to guides, do I really need to have a 100mm of compacted hardcore base and then 25mm of mortar on top? I’m wondering if I can just get away with 50mm of mortar underneath the slabs, having compacted the soil underneath? Will I just end up with a cracked and uneven slabbed area in a couple of years.

If you want to save I’d keep the hardcore and lose the mortar. Big slabs like that will be fine on hardcore/MOT and a bed of sand. Easier to recycle the materials afterwards, too. You should be able to pick up hardcore free from facebook/freecycle. Just be fussy about getting something fairly rubbley rather than just bricks and mix in some proper MOT so it has a few smaller bits and fines. A small area like that can be whacked down by hand. Better than going to the gym

Depends on the stability of the underlying soil but 50 mm or so of scree mortor has been ok for my patio.

I will say that my soil is quite gravely though already

No doubt i will get flamed from the DIY aficionado’s but i slabbed a similar sized area in front of my shed a few years back. All i did was remove the turf and then but a bed of sand down to level the ground and placed the slabs (900×900) on top (no mortar, no hardcore) and it is still fine. The other bit of patio elsewhere i extended about 8 years ago, using mortar and hardcore has sunk!

I’m sorry to hear about your wife’s sudden and unexpected emigration.

You might want to budget for a bag of quicklime. Makes it more difficult for the dogs.

I helped lay a patio for my boss with some 900x600mm slabs and my back was screaming by the end of the second day, 900x900mm must have been torture!
The ground is pretty stable by the sheds, so I’ll dig out 75mm depth, whack it down by hand and stick 50mm mortar underneath the slabs.

My folks back garden is nothing but beach sand and the slabs stayed fine for years. Sometimes I think it’s too easy to over think these things. I laid slabs for my shed on 150mm of red chip with sand on top and again they have been fine (other than ants recently burrowing it out).

I’m in a similar position to yourself and wanted it done properly however in the time honoured fashion of tradesmen never calling back after going to the bother of coming out and quoting I may end up doing the same as you. I hate this town.

I just dug down a few inches, laid sand mixed with cement (no water) and laid the slabs. Still fine years later. The moisture in the ground rises up and sets the cement hard enough to stay level but not actual concrete. Wasn’t too hard tbh.

25mm thick slabs don’t have the weight to stay still, they will dance around on sand alone or even that old trick sprinkle cement on top, bed them proper or get proper 50mm thick ones

Do it rough and ready then if you’re not satisfied with it, raise it and do it properly in years to come.

600 x 900 slaps ought to be pretty stable.

Recently dug out and layed 100mm of MOT and 50mm of mortar, hired a compactor, mixer the works. Was totally unnecessary and alot of extra work I did not anticipate 😥

If I was doing it again I would defo still get proper mot, as soon as I put it down it was rock solid at 50mm and still drained. 2.5cm of mortar (sharp not builders sand) on that would have been perfectly fine unless you are parking your car on it.

Im stil in two minds whether to mix the ballast and cement dry or whether I should get it wet so it sets prpoerly?

Go for a dry mix with just a dribble of water to make it workable. 4 to 1 sand and cement and then water so it’s moist.

As far as the hardcore goes I would say go for it. A tonne bag of scalpings is £60 at the local builders merchants. Should be absolutely fine without if not high traffic but you’ll be using a lot of sand and cement to fill the gap.

I’m sorry to hear about your wife’s sudden and unexpected emigration.

You might want to budget for a bag of quicklime. Makes it more difficult for the dogs.

Two minds with a single thought… 🤣

Im stil in two minds whether to mix the ballast and cement dry or whether I should get it wet so it sets prpoerly?

I just did it dry. Plenty of water around in our garden.

A tonne bag of scalpings is £60 at the local builders merchants. 

They must be mates rates ay perchy? 🤣

I did start to write a proper reply but think minds have already been made up.
I is disappoint though that we’ve not had one mention of “the paving expert,” standards are slipping folks!

They must be mates rates ay perchy

Seems cheap*. 😉

I’m guessing it’ll  be a “bulk bag” of unspecified weight or volume (I.e. less than a tonne, because, let’s face it, how many people really know what a tonne of type 1 is supposed to look like) or it’ll contain a mixture of dust and rocks the size of tennis balls.

B&Q pull this exact  stunt for £45 per “bulk bag”

*not really. In industrial quantities it should be half that-ish

£60 for a ‘Bulk Bag’ then… Just seem to be called tonne bags whenever I’ve wanted one.

I think they’ve started to put out disclaimers when you buy the stuff like that from B&Q etc. Exactly how you would check is beyond me but they’re half the size of a standard FIBC which holds 1000kg of powder quite easily.

The HiAb that delivers it should show the operator how heavy it is when he’s slinging it onto your drive.

I was referring to the cost. 60 snoots for approx 850kg of “scalpings”, scalpings usually being planed tarmac and not type 1.
Money to burn on here I tell thee!

Make sure you smash out the teeth and cut off the hands to dispose of separately, makes it harder to identify the corpse. 👍

ThePavingExpert is a lot of potential reading for a small patio.

I’ve done a big one on dry sand and cement- didn’t turn out well, I was about to relay on mortar but moved house instead!

Just put down a small patio – dug out turf, laid sand, levelled and lay slabs on. If it doesn’t work, sand can be relevelled and relaid, or mortared. If you go with cement and it doesn’t work out, it’s a bigger remediation job.

If you’re not doing sub-base then don’t use any cement – neither dry mix nor mortar. Just lay on sand.
Cement of either type will fail and move and cause wobbles without a proper base.
Sand on the other hand will be adequate without a base, given you’re using big slabs and hopefully can tolerate a bit of movement over the years.

I’ve had sand wash away before and a patio sink after a few years.

Type1 is alot easier to lay than mortar which is a pain to mix. But a thin mortar layer makes levelling flags easier.

Ask the Jordaches!

Firstly, thanks to everyone who offered their suggestions etc. It all helped.
It is all done!
Last week I spent Tuesday digging out soil to a depth of 4″. Then Thursday mixing the concrete and laying the slabs. Went for a 2″ deep wet mix of 6:1 ballast / cement in the end. Used 3/4 of the bulk bag. Hired a cement mixer in the end. For £13 it was worth it!
All levelled and water seems to run away in the direction I’d intended. Spent Saturday pointing it, although getting it between the paving blocks was a faff. Took me about 4 hours probably and its done!
Its not absolutely perfect (some of the slabs are a little higher than I’d have liked) but it looks good and it should last well.
Much better than some slabs just chucked on the ground with weeds poking out everywhere.