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How to build a shed floor foundation?

Hi all,

Im planning to position my shed to the yellow area indicated in the image.

The exposed aggregate concrete path has a slope towards timber fence.

Will remove the plants in the area and pour a concrete pad that is levelled to the path edge. Then lay a levelled paver floor for my shed to sit on (Shed 80cm deep x 200cm long, Paver 40cmx40)

What I am concerned about atm is the concrete pad might sink over time due to the ground underneath settling. Cannot fit a compactor in where the concrete pad is going to be - too narrow.

What can I do in order to avoid this potential problem prior to pouring?

Also is it a good idea to have a levelled paver floor sitting on the exposed aggregate concrete path and concrete pad? or is there a better preactice? And any other things I need to pay attention too?

TIA

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EricL

Hello @CarlL

Shed manufacturers recommend that the shed be placed directly over the concrete slab in order to anchor the shed properly to the base. Lifting the shed over the base and onto the paver floor will not allow you to anchor the shed properly. You do have the option of placing the pavers inside the shed once it is anchored in place. The pavers will keep your stored items in the shed off the concrete base and prevent them from getting wet should water enter the bottom of your shed.

Before pouring the concrete, I suggest using a Trojan 205mm Tamper on the soft soil section to compact the soil. You can also add some gravel to reinforce the soil. I suggest having a good look at this guide - How to pour a concrete slab by @tom_builds.

Let me call on our experienced members @Dave-1, @Nailbag and @AlanM52 for their recommendations.

If you need further assistance, please let us know.

Eric

Dave-1

Good Evening @CarlL

@EricL has pretty well covered the suggestion I was going to make, right down to the Tamp bar. I have used one a lot and it does a really got job of compacting the earth tho you will feel like you have had a hard workout at the gym! 🙂

Drainage is about the only thing thats missing from your scenerip. You will be effectivly creating a dam across the pathway with pavers, it will drain, just slowly. You could either install some ag pipe underneath the slab to join both sections of the garden bed or install some grill drain to provide a path for the water to flow through.

Dave

Nailbag

HI @CarlL

my first obvious concern is that you intend to pour a slab over the existing drain. You will need a plumber to raise this to above the top of the new slab level then cut it flush and reinstate the grate on completeion.

Next is to ensure the fence is not used as the rear edge to support the new slab into. This should be independent to avoid it bowing outwards into your neighbours yard.

You will need to dig the garden bed out and use tie-rode both horizontally and vertically to bonds the slab to the existing path to avoid it splitting. A more secure method would be to use a demolition saw to cut along the line of the shed slab and then. make smaller cross cuts within the area. Then remove the old sections of exposed egg path. Then frame out and pour a new shed purpose slab independent of the pathway.