Flagstone Path - How to Fix Unstable Stones

We just put in a small flagstone path ourselves and I think we did it all wrong: the stones are pretty unstable. We did it with little research and no experience, and on a very tight budget so we cut a lot of corners.

I think the main problem is that we didn't actually use flagstones. Someone was giving away granite tiles (12x12x3/8") that we liked, so we broke those up and used them as the main stones. I think they're probably just too light. But I'd like to understand what all we did wrong before trying to fix the problem.

The path is on our front yard, about 3 ft wide and 20 ft long, gently curving, and gently downsloped -- there is about a 1 ft decline over the 20 ft distance.

First, we put in benderboards on the sides of the path. We did this without scraping the underlying dirt to be perfectly flat, so the tops of the benderboards aren't even from one side to the other.

Second, we poured in several bags of moist, all-purpose sand. Because the dirt wasn't flat and tops of the benderboards are uneven, the sand depth varies from 3/4 inch to 1.5 inch. We tamped it by pushing down with a piece of wood board -- we did not use a metal tamper.

Third, we laid the granite tile pieces. Their sizes varied, but on average they are about the size of a business-size envelope. Then we filled the spaces between them (which are about 1" width) with 1/4" black beach pebbles.

Right away the stones did not feel solid. They sank and shifted when walked on. After just one day of use, several steps are already out of place. And worse, the pebbles that were between the stones are are all over the place.

So, I think the main problem is that our stones pieces are just too small and thin. But I wonder if not tamping the sand was also a problem? In a normal flagstone path, what keeps each flagstone from shifting under the weight of a person? It seems to me that even if the sand had been packed very tight, it would eventually dry out and become fluid, and would not keep flagstones from shifting under people's weight. How does that really work?

I'd appreciate any input. Thanks.

 

Flagstones should be set in a wet mix, not just sand. That way when the mix dries, the flagstone can't move.

 

We were trying to follow how-to instructions given in Sunset Magazine, where they have you do it dry:

Step-by-step: Flagstone path

So you think it simply won't work?

 

There is no stability there, other than the sides. Do it my way & you can drive your car over it.

 

have laid flagstone in cinders from an elec generating plant & never had a problem - not as long as there's a good granular compacted base course,,, then again, never did try to lay tile on 1 1st place, get some STONE at least 1 1/4" thick,,, put in a good base course w/drainage,,, rent a plate compactor & do it right OR plan on doing it over