Laying a foundation with a dry mix

[martyc]

Hey there,
Have just dug out a foundation for my garage.
A mate who does a fair whack of building said i should get enough dry mix and just fill it in dry and sprinkle with water a little every now and again.
This sound reasonable or must it be mixed with water prior to laying?
Foundation is ~400 deep 300 wide(single block/storey wall)
Cheers,
Martin.

 

[nstreet]

I would lay it wet, I cant see how a little water now and then would work. Surely the surface would form a crust and stop any further water penetrating after a short time

 

[noseall]

doing a dry mix is an old builders trick to try and save on volume.

don't do it.

there is a standard slump mix for foundations, the last thing you want is air in the concrete foundations of a building for goodness sake.

 

[JohnD]

sometimes, if you have a wet site, you can pack in dry lean mix to soak up the damp remaining after pumping, and give you a base to lay your real concrete onto. It isn't treated as concrete, its treated as a sub base, instead of using stone scalpings or something.

 

[martyc]

Cheers lads...ill get a mixer so and mix it up.
Thanks again.
Marty.

 

[^woody^]

Remind me not to let your mate on any of my jobs

 

[martyc]

Will do woody!

 

[martyc]

Actually just found this here......

www.drymixproductsco.com/products.html

--TO BUILD A BLOCK OR BRICK WALL--
Dig a 16" wide x 8" deep trench the length of the wall. Fill this foundation with DRY MIX CONCRETE and cure for 3 to 4 days.

Is this a totally different product i wonder?
Marty.

 

[^woody^]

It still has to be mixed with water, despite its' name.

Otherwise, I wonder how the "Dry Mix Mortar" will work?

There is a similar UK product for fence posts, which you do put in dry and add the water after, but this is specially prepared and bagged, and you can't do it with normal sand/ballast mix done at home. It is also not 'foundation grade' concrete.

Nice try, but it's a bit of mixing for you I'm afraid

 

[martyc]

Cheers Woody...thanks for the clarification...im new to this (obviously!!)
Will see if a ready mix truck will deliver such a small load in the morning...only need a cubic metre, otherwise ill be mixing!
Marty.