[sandim]

As newbies we're always learning and recently went up to become ICPI certified. We're very excited about taking our hardscaping skills to the next level. Previously for a setting bed we were using stone dust rather than washed concrete sand. Now we know better. (The things you learn when you go solo and want to do things as right as you can) We also do a lot of flagstone or slate walkways and bluestone. We're now thinking the same idea would hold true for any type of walkway/patio...sand as a setting bed rather than stone dust, but we're thinking due to the thickness and variation of the real stone maybe 2" would be better. Are we on the right track?

As always, thanks for sharing your knowledge!

[TrickyDick]

Don't be too quick to assume that everything you hear at ICPI is gospel. Remember that they are an organization that has an agenda, part of which is standardizing the installation of their products to make it easier for a lot of inexperienced contractors (and homeowners) to install them so they can sell more blocks. We install pavers more or less according to ICPI specs, mostly because we don't do a lot of it and I feel better following the literature. For natural stone we always install in stone dust. What stone dust actually is varies a lot geographically (concrete sand is pretty much the same everywhere) and some stone dust is probably not as suitable for a setting bed. Ours makes an excellent setting bed.

As far as thickness....I would leave my base grade a half inch lower than the thickest stone.

[Paul]

I'll Hold my comments.............

[johnkeegan]

For natural stone walkways and patios we've always used a setting bed of stone dust because the uneveness of the thickness requires each stone laid to have the stone dust packed forcefully underneath it. Sand like the type used with paver setting beds doesn't pack well... in my opinion.
...Remember, though, your base preparation should be the same as with the pavers.

[GLAN]

All of what I have done with with natural stone paths and patios......set right into the soil.....We excavate what needs to be removed. Tamp and then set stones using soil.

Ok.......may seem strange.......for me it works, and it works well.

I also try to have something growing between the stones.

The few brick jobs we have done......of which was some time ago.......Same process.......only excavate what I needed for depth of brick and about an inch of sand. Tamp the soil and then proceed.

This is why I do what I do..............Earth / soil that has been a constant through time......where's it going?......is it settling?........NO...........I considered it to be a base. I have had very little or no settling or shifting over the years.

I have installations that go back 25+ years.....they still look pretty damn close to as it was when installed..........I can't say that for most all paver jobs I have seen.....and were done by others......I've seen far to many pavers go to crap 5 years after install.

[sandim]

Hmmm, good points. Ok, well, I feel better about our previously installed stone walkways. I suppose I can see why they want the pavers installed in sand for drainage and efflouresense. Packing the stone dust underneath the flagstone does make sense to me due to the unevenness of the stone. Much appreciation.

I love stone.

Thanks!

[Fine Edge]

Ditto Paul.

We don't use sand.

[johnkeegan]

Freeze... Freeze... Freeze....
Thaw.... Thaw... Thaw...

Be sure to read that up and down... up and down.

If you don't think the soil expands and contracts why put a crushed stone base under anything?

[Stonehenge]

Originally Posted by Fine Edge

Ditto Paul.

We don't use sand.

Paul uses sand.

We don't use sand under pavers, but we do under flagstone, to help us set each stone. We usually shoot for 1-1.5" sand thickness before the stone goes in.

[Fine Edge]

Clarification-
Ditto Paul on holding many of my comments concerning ICPI.

We don't use sand under pavers but will use it on simple flagstone paths.

[sandim]

Ok, so basically what I think I'm getting (after a long Sunday of dealing with too many stupid clients)

Basically what I'm getting is that a setting bed of stone dust or sand, either way, is ok, just depends on your preference? We've been doing what we here in CT call Process Gravel for the base, with the right depth and compaction level (thank heavens we did something right in our previous jobs). So sand or stone dust either way for the setting bed? No shifting of the stones with sand?

[Paul]

ICPI is setting a standard. However it is very hard for everyone to follow that one standard. If everyone did you wouldn't see as many failed installs. Not everyone has the necessary plate tampers as most being too small under 4000 lbs compaction force. Under excavation, wrong gravel base, poor sub base preparation, building on poor soils, the list goes on. Any one of them can and will lead to a sub standard installation. If you think that 1" of sand is going to make or break your installation your wrong.

[AZTLANLC]

Amen to that.
We lay all of our paver and stone on 1/4" or 3/8" clear gravel after we put 6" or more item 4 base depending on project I like using 1/4" gravel because I can walk on it I can install it even if it rains, and don't have to worry much about migrating near steps.
I honestly don't buy ICPI argument about using it or it won't interlock pavers.
I 100% agree with Paul that most failures will be on the base material and sub-base, after that edge restraining, pattern, pitch no sand in the joints and last the type of bedding material.

[TrickyDick]

Doesn't your sand just keep washing through into your clear stone?

[signguy]

well i think your all right, yet diffrent stone(ie thickness) and site grade should dictate the type of bedding used.I supply a lot of flagstone here on the wet coast and have seen good and bad installs.we supply both concrete sand and crusher dust.If you are working with a 11\2" product on level ground with good drainage.Then sand is your best choice,it's easy to work with and cheaper than dust.Yet on any kind of slope I always recomend dust.This product drains better and won't wash out if put on ground with poor drainage.AS for using soil, its just lazy,if you want to do planting between the stones.Do the complete job and when you are happy that the product is bedded suffisiently,take a shop vac and remove grout spaces (don't go crazy) then replace with a high compost soil and do plantings in that.your soil will settle with the sand and provide a good growing medium for creeping plants. well thats my 2 cents LOL