ᐅ Slope Angle Decorative Gravel

Hello everyone, for the outdoor areas, I’m planning to cover some sections with decorative gravel, probably Carrara, sized 15-25mm (0.6-1 inch). The base is crushed stone, compacted, and on top of that, there will be a weed control membrane.

What is the maximum slope I can lay the gravel on without it slipping due to wind and weather? Does anyone have experience with this?

I’ve read a bit, for example that it’s generally good to have gravel with mixed sizes so the stones lock together better. However, I prefer to use rounded gravel, so locking won’t be much of a factor here.

I’m also not very keen on using honeycomb grids.

So again, the question is not how steep I can make the slope, but rather how steep can I reasonably go with the gravel mentioned?

Thanks a lot, and have a great weekend everyone!

In my opinion, you are asking about the angle of repose, which can practically only be determined experimentally. Either someone has already done this (try searching online), or you have the opportunity at a building supply store to pile up a heap (cone) of material. The way it falls will likely show the steepest angle that will remain stable over time; it won’t hold steeper permanently.

Sure, it is clear that this is the absolute limit. However, I would also doubt whether it would hold up practically over the long term...

Why not? Do you have any new insights? Have you already laid gravel? Photos?

No, I’m asking so that I can set the slope properly and won’t be surprised later...

How many meters (feet) of elevation difference are we actually talking about?