Extending a shed base

[Beagle1]

Hello

I am extending a concrete shed base from 8'x6' to 10'x10', to a depth of 2", but with 4" around the edges. The depths were what a builder said would be adequate. This is for a summerhouse.

My questions are:

How many ready-mixed bags of aggregate will I need? Or is it a lot cheaper to buy 'all-in ballast'.

Do I need hardcore/ type1 for such a shallow construction?

How long will it take to harden off?

Many thanks.

 

[Beagle1]

Any takers?

 

[r896neo]

2'' may well crack i'd beef it up to 3 at least probably if it was me 4.

Check out the calculator sticky in the building section for quantities of ballast

I would put some compacted mot under there especially if you are only putting 3 inches down. I would also tie it into the existing concrete by drilling holes in it half way down and sticking some bits of steel re-bar in there otherwise the new bit may settle differently.

It will be hard enough to build on the next day assuming it was poured the morning before. just leave it 24 hours after pouring. it won't be completely cured for weeks but that is irrelevant.

 

[Beagle1]

Thanks for your help. The shuttering I've got is 5" deep, so I can afford to have 1" mot (not sure what that stands for) compacted and 4" ballast.

 

[Thermo]

dont bother just fill it all with concrete

 

[Beagle1]

I think the reinforcing rods are worthwhile though.

 

[Thermo]

wont hurt to put them in

 

[r896neo]

If you already have it dug out and shuttered i agree to just fill it with concrete. As for the pins just make up a goup of pure cement and water and smear it round it then twist it into the whole. Be careful it goes off pretty quick!