What did I do wrong with my flag stone path install?

[jetdriver]

I dug down 7 inches, put in a base of 6 inches 3/4 minus, then 1 inch of sharp sand and then compacted with a vibration compactor.
Then laid out the flag stones. And ran the compactor again with cardboard to protect the stone. But these there not very thick. At best, 2 inches thick, but most 1 to 1-1/2. We filled the gaps with what locally is called "fractured granite," that was supposed to harden over time, and then set everything in place...... according to the landscape place we buy stuff from.
It has not worked out. The winters just pop all the flags up with hoarfrost. We have no issues with 2 inch thick pavers or brick, which was used in other areas with the same base.
I really don't want to pull all these out and reset them. I've bought a whole lot of Ez-Sand.
But right now I really don't have a clue as to if this will work.
Any and all suggestions, are welcome. Even ones that say I'm an idiot.

Had the same issue with brick around my back deck. I dug it to 3 feet. filled with 2 1/2 feet of 3/4 inch clear stone. Put crush over that. Sand would be good too. All fixed. Water can't stick around in the clear stone.

 

[Gord Baker]

I dug down 7 inches, put in a base of 6 inches 3/4 minus, then 1 inch of sharp sand and then compacted with a vibration compactor.
Then laid out the flag stones. And ran the compactor again with cardboard to protect the stone. But these there not very thick. At best, 2 inches thick, but most 1 to 1-1/2. We filled the gaps with what locally is called "fractured granite," that was supposed to harden over time, and then set everything in place...... according to the landscape place we buy stuff from.
It has not worked out. The winters just pop all the flags up with hoarfrost. We have no issues with 2 inch thick pavers or brick, which was used in other areas with the same base.
I really don't want to pull all these out and reset them. I've bought a whole lot of Ez-Sand.
But right now I really don't have a clue as to if this will work.
Any and all suggestions, are welcome. Even ones that say I'm an idiot.

I have found that when using 24"x24"x2" Patio slabs that a 3/4" or 1" sheet of Styrofoam keeps them even and I have never had a frost problem in Southern Ontario

 

[deezler]

Jasper, some pics would help, especially if you had any during the installation.

Wild guess: do you have clay soils? Sounds like you may have dug a bathtub. I would tend to align with the other comments about drainage around the area. I'm not sure your exact material choices are to blame so much as the installation environment. Doesn't really matter what you choose for a base if you have a clay bathtub around it.

 

[jyoutz]

In my *opinion* one inch of concrete isn't going to accomplish much. I can take my foot and put a piece of 1" concrete slab with one side on a rock - and break it with a good kick.

The freeze is going to do the same.

Concrete is unnecessary and counter productive. It heaves. A good base of compacted crusher fines is all that is needed.

 

[EddieWalker]

The idea for concrete to replace the sand was to remove a place for water to remain between the compacted gravel and the flagstones.

But I think the real solution is to dig down deeper and install more road base gravel that is highly compacted. A solid concrete base would be better, but it's more work and a lot more money.

Concrete heaves when the ground below it freezes when it's saturated with moisture. The reason for digging down below the frostline is to have the concrete on solid, dry soil that will not be saturated with moisture, or too far down that it's insulated from the freezing temps above.

For a walkway, I don't think it's practical, or even done anywhere, to dig down below the frost line. Where I'm at, that's about 12 inches. Concrete walkways are just 3 1/2 inches deep and there is no noticeable movement from freezing.

Since it's a lot colder where this walkway is located, it would make sense to make the base under the flagstones the same depth as every sidewalk in that area.

 

[Mcdust]

I dug down 7 inches, put in a base of 6 inches 3/4 minus, then 1 inch of sharp sand and then compacted with a vibration compactor.
Then laid out the flag stones. And ran the compactor again with cardboard to protect the stone. But these there not very thick. At best, 2 inches thick, but most 1 to 1-1/2. We filled the gaps with what locally is called "fractured granite," that was supposed to harden over time, and then set everything in place...... according to the landscape place we buy stuff from.
It has not worked out. The winters just pop all the flags up with hoarfrost. We have no issues with 2 inch thick pavers or brick, which was used in other areas with the same base.
I really don't want to pull all these out and reset them. I've bought a whole lot of Ez-Sand.
But right now I really don't have a clue as to if this will work.
Any and all suggestions, are welcome. Even ones that say I'm an idiot.

Hi, as a Caretaker one of my headaches is a big pool with a granite coping that was coming adrift. A local mason came and re grouted it with poly sand and a bit oh a "duh" attitude. The following spring another mason came and reset and grouted all with real mortar. End of story and my opinion of polysand is obvious

 

[charlessenf]

I dug down 7 inches
put in a base
then 1 inch of sharp sand
then compacted with a vibration compactor.

I dug down 7 inches
then compacted with a vibration compactor.
put in a base
then compacted with a vibration compactor.
then 1 inch of sharp sand
then compacted with a vibration compactor.

Seven Inches? Is that BELOW YOUR FROST LINE?

Is the path in a low, maybe moist area?

 

[pacosperson]

I dug down 7 inches, put in a base of 6 inches 3/4 minus, then 1 inch of sharp sand and then compacted with a vibration compactor.
Then laid out the flag stones. And ran the compactor again with cardboard to protect the stone. But these there not very thick. At best, 2 inches thick, but most 1 to 1-1/2. We filled the gaps with what locally is called "fractured granite," that was supposed to harden over time, and then set everything in place...... according to the landscape place we buy stuff from.
It has not worked out. The winters just pop all the flags up with hoarfrost. We have no issues with 2 inch thick pavers or brick, which was used in other areas with the same base.
I really don't want to pull all these out and reset them. I've bought a whole lot of Ez-Sand.
But right now I really don't have a clue as to if this will work.
Any and all suggestions, are welcome. Even ones that say I'm an idiot.

It sounds like you tried to do everything right. Of course, the problem is water. Nearly everyone uses their driveway as a drainage ditch in one way or the other. I had similar problems until I read a US Forestry Service manual about building and maintaining woodland roads. Nearly every bit of it concerned controlling water flow. So I bit the bullet and installed a drainage field under my driveway. It worked. I believe if you control the water runoff from rain and snow melt your previous good work will pay off. Maybe a perimeter pipe system would be enough if the driveway has any crown at all.

 

[Rockbadchild]

I dug down 7 inches
put in a base
then 1 inch of sharp sand
then compacted with a vibration compactor.

I dug down 7 inches
then compacted with a vibration compactor.
put in a base
then compacted with a vibration compactor.
then 1 inch of sharp sand
then compacted with a vibration compactor.

Seven Inches? Is that BELOW YOUR FROST LINE?

Is the path in a low, maybe moist area?

he doesn't need to be below the frost line its not a footing, our frost line is 6 foot can you imagine digging 6' for a walkway ? ... 6 to 8 inch base is on par for walkways even for us up north.

 

[Little Red Tractor]

Not sure it will help, but if you can get a look at the soil map of your property. Most USDA facilities, especially in agricultural areas, should have them. You may have soils like I have. Essentially without good drainage in your soils, you're always going to have the problem. Cement may fix it as others have said, but the moisture of the soil beneath may still wreak havoc in the deep cold.
Lots of luck with the project.