How to construct base for 'Build A Shed' garden shed?

Question

I am about to buy a garden shed from Bunnings (Build A Shed Skillion Series base dimensions 2.3 by 1.2m). I'm not concerned about assembling the shed but nowhere is there any guidance about constructing the base to which the shed will be attached, except, Bolt down kits & anchor bolts are included in the package.

Presumably a concrete base would be best. My questions are:

1. What thickness?

2. Should the base extend a certain amount from the base of the shed?

3. Would consider ordering a 'mini mix' concrete delivery but determining the amount could be tricky. If there is excess do they take it away? The site is behind a villa unit so no opportunity for disposal.

Any advice would be appreciated,

with thanks, John

JacobZ95 · Accepted Answer

Hey John,

1. As a rule of thumb 100mm is a good thickness for a slab. In conjunction with reinforcing mesh this will give you a good base to attach your new shed to.

2. The slab should extend out around the shed at least 100mm to allow for the concrete anchors. If they're too close to the edge they can "blow-out" the side of the slab. This will also help with stopping water ingress assuming the slab is edged correctly to run away from the shed.

3. Generally speaking, concrete delivery services will not remove excess concrete as it is prone to "going off" inside the truck. Bunnings do offer Mixer Hire if over ordering is a concern.