ᐅ Concrete slab foundation for garden shed

Hello everyone

I have a garden shed with a footprint of 6m x 2.5m, which is 15m² (161 sq ft). Since I want to create a walking area all around it, the foundation will expand to 8m x 4.5m, which is 36m² (387 sq ft).

At first, I thought about making a full concrete slab foundation, then building an underlying frame from squared timber on top, and placing the garden shed on it. This would also secure it firmly in place.

However, I must admit that the cost of the concrete slab would already exceed the price of the garden shed, and I feel this might be overkill.

After contacting the garden shed manufacturer, they said a simple slab foundation made of paving slabs would be sufficient. However, I definitely want to anchor it securely.

So here is my planned approach:

I will create a slab foundation using paving slabs. Beneath them: 15cm (6 inches) of crushed stone, 5cm (2 inches) of gravel or grit for bedding, then the slabs on top.
At the corners, I will drill down 20cm x 80cm (8 inches x 31 inches) and make isolated pad foundations.
The squared timber frame will be anchored at the corners through the paving slabs into the pad foundations using bolt anchors. The squared timbers that form the inner frame (supporting the floor above) will only be laid on the paving slabs and not screwed down.

Now my questions:
1. Is it problematic to anchor only the corners?
2. Do I need a frost barrier (frost skirt / frost protection) around the slab foundation?

Thank you very much
Best regards, jumbo125

You could place an edging border under the edge of the small shed and embed it slightly in concrete. Then you can securely screw the shed to it. We installed our metal garages this way, and it works very well. In our experience, a frost apron (frost skirt) is not necessary for this. The depth of the border is entirely sufficient.

motorradsilke schrieb:
You could place edging around the base of the shed and set it in a bit of concrete. You can then screw the shed securely to this. That’s how we installed our metal garages, and it works really well. In our experience, you don’t need a frost barrier for this. The depth of the edging is also completely sufficient.

Do you mean by border - curbstones?

Yes, exactly. The 30mm (1.2 inches), 8mm (0.3 inches) width.

motorradsilke schrieb:

Yes, exactly. The 30 (12 inches), 8 (3 inches) width.

Did you set the curbstones in concrete?

motorradsilke schrieb:

You could place a border around the edge of the little house, embedding it slightly in concrete.

jumbo125 schrieb:

Did you embed the curbstones in concrete?

That’s how I would understand it.