ᐅ What type of base is suitable for a garden staircase made of sandstone steps?

Hello forum,

I want to build a three-step staircase using sandstone steps. I have already built steps using concrete. Gravel/aggregate, then lean concrete, and the step on top. Can I do the same with sandstone? I read different things about sandstone. Pozzolanic lime, lime, no cement... Can the sandstone simply be placed directly onto damp soil?

I would really appreciate any clarifying help.

Thank you very much!

Directly on soil is possible. No cement needed; trass works.
Sandstone is relatively soft. When stresses occur, the stone cracks instead of the mortar.

haydee schrieb:

It works directly on soil. No cement needed, pozzolan works.
Sandstone is relatively soft. When stress occurs, the stone cracks rather than the cement.

Thank you very much for the quick response. I only know pozzolan as part of pozzolan cement/concrete, which would then be quite hard as well. If I don’t want to place it directly on soil, what exactly should go underneath the stone?

You can place the steps on a gravel bed; 20-30cm (8-12 inches) should be sufficient, and of course compact it. You can then adjust the exact height using the mortar bed (3-5cm / 1-2 inches). Trass cement works well with natural stone, as it prevents or significantly reduces efflorescence.

Philfuel schrieb:

You can place the steps on a gravel base, 20-30cm (8-12 inches) should be sufficient, and of course compact it well. You can then adjust the exact height with a mortar bed (3-5cm / 1-2 inches). Trass cement works well with natural stone because it prevents or greatly reduces efflorescence.

Now I have to ask a probably silly question, sorry. Trass cement is harder than sandstone, right? Or won’t that cause any stress issues because of the gravel?

Pozzolanic cement breaks cleanly out of the joint. For whatever reason. In the old wall, the joints are repaired every few years.