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Groundwork & Foundations

Dry mix concrete as patio sub base?

I'm putting in a patio approx 8mx3m at the rear of our garden. The top soil has been taken down to the correct level and ready for sub base. I'd prefer to put in mot type 1 but given the closure of many suppliers it is hard to come by. Due to the business I run I know a few folk delivering concrete who are still operating. Is there any reason a dry mix concrete or similar cannot be used for the sub base in place of the type 1? Many thanks.

7 Answers from MyBuilder Groundworkers

Best Answer

If your worried about it throw some water in and knock it up a bit so it definitely goes off.

In extremely dry conditions a 'dry' mix might just not go off properly meaning you'll be laying on a soft uncompacted sand as a sub base.

If it's just a garden patio you don't really need much of a sub base it's not the m25.


Answered 20th Apr 2020

it’s fine makes a better base anyway as long as you have all the topsoil out and are down to hard as it will sink if you’re not. but will be 3 to 4 times the cost of type one depending on concrete cost 8 x 3 at 150mm deep is 3.6 cube. Depends how much you need to fill if it’s a lot going to cost heavy if only 100mm all over it’s not going to be much more expensive.but if you have 300mm to up fill it will be 7 cube x say £120 = £840 14 tonne of type in @ £20 =£280


Answered 20th Apr 2020

Yes as dry mix concrete would be fine but you would still need to compact it the same has type one to give a solid foundation


Answered 20th Apr 2020

Hi there is no reason why you can’t use this as long as you compact it without using water.


Answered 20th Apr 2020

Touch of water in the mix and Concrete is fine.
But you can still get type 1.


Answered 20th Apr 2020

Nothing wrong with using concrete as a sub base, what you want is a lean mix and when you have levelled the base run over it with a whacked plate.


Answered 20th Apr 2020

You can use dry clean mix but it needs to be consolidated and a least 150mm deep in my opinion


Answered 20th Apr 2020

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