How to make a rock cairn on a slope?

BodgeJobsRUs

Hiho

I have a small area that I wish to build a stone cairn on.

Unfortunately, it's on a slope, and I want it to abut a concrete slab, but needs to be raised. 

I have my stones, two bags of blue metal, and a 20kg bag of mortar. I also have some planks I can use to create form work but I'm after a circle shape. I also don't want to spend more money on edging. 

The ground is pretty much just sandstone. 

What should I do to raise it up so the base starts just below the top edge of the concrete? Should I shovel some mulch to create a sort of supportive bed for the gravel whilst the mortar sets?

Large pot for scale.

Thank you!

MitchellMc

Welcome to the Bunnings Workshop community @BodgeJobsRUs. It's great to have you join us, and many thanks for your question about levelling a base.

To create a circular form, you’ll need a flexible material, such as plastic sheeting or thin plywood, to shape and hold the structure. Secure the material in place with stakes to create the desired circular shape. This approach will help you form a level and stable base for your cairn.

Alternatively, you could start by cementing the rocks together on the lower side of the slope first, gradually building up to level the base. This method avoids the need for additional materials and creates a natural, organic look. If the ground is soft, consider compacting the area or adding a supportive layer of blue metal to ensure stability before adding the mortar.

Both methods can help you achieve a raised, circular cairn that aligns with the concrete slab edge.

Please let me know if you have any questions.

Mitchell