Dry-spreading sand/cement as alternative to Slablayer

IM

I’m in the (very slow) process of laying a c55m2 patio in my garden.

Last year, I dug out the old crazy-paving/lawn, framed out the area to be slabbed, and filled with compacted MoT1.

I then ran out of money/good weather…

Now that the sun’s appearing, I was planning on laying/compacting a layer of sharp sand on top of the sub-base as a bedding layer, to get things smooth and level, ahead of paying someone to do the actual laying of the slabs.

However… Finances mean I’m contemplating doing it myself.

In the name of an easy life, I was looking at Blue Circle Slablayer https://www.wickes.co.uk/Blue-Circle-Ready-To-Use-Slablayer---20kg/p/153707 as it doesn’t claim to need mixing (you just empty the bag, sprinkle with water, then pop the slabs down on top – allegedly).

For the space I’m looking at though, it would be prohibitively expensive.

Is there any reason why I couldn’t take the same approach with a sand/cement mix? i.e. Mix it in an appropriate ratio, but dry spread it on top of the sand bedding layer, then wet and lay the slabs?

Would appreciate the thoughts of folk who know what they’re talking about.

bris

That's exactly what you do. Just mix up 1 part cement to 6 parts sand.


Spread and screed then lay. The the mix sets naturally using the moisture in the ground, no need for water.

ceredigion

bris wrote: »

That's exactly what you do. Just mix up 1 part cement to 6 parts sand.


Spread and screed then lay. The the mix sets naturally using the moisture in the ground, no need for water.

Not if you are working for me you don't.
Two choices in life, cheat and hope or do it properly.

davemorton

Buy a second hand cement mixer from ebay, use it to do the patio, then sell it for round about what you paid for (so long as it does not work obviously).

Davesnave

davemorton wrote: »

sell it for round about what you paid for (so long as it does not work obviously).

And if it does work, would the OP expect to make a profit ? :huh:

Furts

ceredigion wrote: »

Not if you are working for me you don't.
Two choices in life, cheat and hope or do it properly.

I cannot disagree here - that is the proper way and a simple question should be asked by anybody saying use dry sand and cement and wait for the moisture in the ground to make it hard. Sand and cement is also used to build walls - a simple fact of life. Would anybody build a wall with a dry mix or would they first mix up some mortar?

There is a half way house for slabs and if sharp/grit/plastering sand is used then this can be damp and cement added into it. Produce a "dry" mix and away you. Not ideal but with a bit of care it does work - the secret is the sand selection.

bris

ceredigion wrote: »

Not if you are working for me you don't.
Two choices in life, cheat and hope or do it properly.

Rubbish, slabs have been laid this way for years and it sets pretty quick.


Your not building a wall, you do not need a wet mix to lay slabs for the OP's project.


Disagree all you want but your way is a waste of time, I hope you don't charge by the hour.

vixen_vg

I'm looking at doing something similar and like you looked at the Wickes products.
Be interested to hear how your project turned out ... i realise it was last year.
i calculated that if we were laying the full patio on this pre mix we'd be spending around £90 + if I used the wickes Slab layer.
think I'm just bogged down with info and calculations now, and prob we just need to crack on.
Dab and Go method I think , but I'm sure someone will disagree !
Love to hear how your project turned out.

V .

jsmi4s

I would also love to hear what you used and how it went. :-)

trphil

I laid a patio using a dry mix over twenty years ago, I covered it with decking two years ago. I removed some of the original patio underneath so that any rain water would drain into the ground rather than sit on the patio (foolishly I'd laid it dead level and it is surrounded by planters so was very slow to drain after heavy rain) - it was an absolute nightmare getting the slabs up as they were so firmly fixed! Also in the whole time it was down I never had anything grow up between the slabs.

Heedtheadvice

Ceredigion is right as to what is the best method to produce a good concrete base.
The proroess of mixing wet ensures that each grain of sand or aggregate is coated with cement and a homogenious mix can be produced. That gives far fewer voids and week spots maximising strength of the base. The base is quickly stable thus reducing the risk of pointing cracking if done.



However DIYers, gardeners and some professionals do use the dry mix method as it is much easier to lay the slabs and the cement does 'set' well over time but not any where need as consistent as a wet mix so can have week points or less resilient to some weeds and roots getting through. this can also happen between slabs and base if laid dry.
A trade off between quality and speed/ease of laying.


To ensure adequate run off surface slabs should be laid without hollows and the overall level given a run off away from property of 1 in 200 plus should not be higher or breach damp proof coarse level (or ventilation bricks) if adjacent to property walls!