Foundations in Clay

[aaront]

I've dug the trench for the foundations for a small sleeper wall extension (18") under my bathroom floor.

The soil is clay - are there any differences for the mix or type of concrete for setting foundations in clay considering the lack of drainage.

Thanks.

 

[masona]

Not sure what you mean by lack of drainage.

 

[aaront]

I meant that clay lacks the drainage qualities of normal soil so the cement will not lose water as quickly.

 

[masona]

Try looking at www.pavingexpert.com for your answer.You can also get Fast rapid Cement to speed up the progess.I normally use 1 part cement & 3 part 3/4 ballast for footing.

 

[MANDATE]

I'm fairly sure you have no need to be concerned.
A lot of concrete,these days is laid on a waterproof membrane, where there is no drainage.
The setting of concrete is not dependant on the water draining away.
The water is the means of starting a chemical reaction and the biggest mistake people make is by adding too much and making the concrete weak.
If the correct amount is used there is no water to drain away, in fact you will sometimes see concrete covered with sack cloth and damped to slow down the curing time.
Not only that' but footings always have to be to a depth so it is firm enough to take the weight and you can't do better than clay