Some areas around here require a permeable application.

So the base is #2 stone, then #1 stone, then instead of skimming it sand we screed off #1A stone. Lay them like normal, and instead of poly or mason sand we sweep in #1A's (provided the pavers used allow for a joint wide enough)

I think the key to avoiding sink holes is the same for either application though, not installing over fresh backfill, and making sure the base is thick enough. I go a little overboard and like the base at like 6", better safe than sorry.

It works just as well and applies to local requirements.

Crusher Run and stone dust like you use though is how I was taught also, and works great with poly sand for moving water off the top, similar to concrete.

 

My thoughts also. When I use permably pavers thats what I do with just the stone.

 

I am from a different area with different terminology, but what exactly is "site pack", and "stone dust"??

i am assuming stone dust is what we call crusher dust or crusher chips(or 1/4" minus), and that site pack is like a 3" minus gravel or something, anyways, your method is fine, but my experience has been that screeding gravel is a lot more time consuming than screeding sand. Also, the idea of putting course sand under bricks is that when you run the packer over the top of the bricks, the sand will be drawn up between the bricks, and you will have the sweep sand comming down and base sand comming up, to achieve maximum interlock, you wouldnt quite get that with the gravel. Another reason they want sand under the bricks is because it does not hold water, and the fine stone dust does, because it is much finer than sand, in which case it can be an issue if it holds water and freezes.

Regarding those other jobs that you have fixed up that had issues, I agree with the other guy that the reason is probably in poor preparation, and likely because subsoil was removed and replaced with insufficient compation.

Regarding polymer sand, I consider polymer sand more for maintenance/weeds than for preventing water going through the bricks, I dont think there is anything wrong with some water going through with the regular sweepsand. Nobody seems to want to pay for proper polymer sand installation around here, too competitive...

 

The lack of a 1" clean sand setting bed is like trying to reinvent the wheel. The sand bed is required for all heavily loaded or serious paver installations around the world in all climates. I have never seen polymeric sand used on a major paver installation, especially the 10-30 acres sites that carry extremenly heavy loads for unloading ship with a straddle loader that are only few feet above high tide, but they do a serious job on subgrade and base preparation.

For a small patio, you can get away with some sloppy installations that do not agree with national and international suggestions.

 

Stone dust is pretty much like concrete sand and site pack is a 3/4 gravel/stonedust mix.

stone dust compacks better then fine sand imo and just doing a base in stragiht gravel is just something I perfer not to do.

I never you poly sand for a base I use it just to sweep in the joints so weeds will not come up. what really locks pavers into place is the edging that you use

 

Heres what I do for pavers...first and foremost we make sure that we have dug an opening 1' and . (make sure its sloped properly if its necessary).

Then I use landscaping felt,crushed stone (5"),3/4 down 6" ,tampered then course sand.

 

Thats pretty serious, it sounds indestructible. With that depth of base and landscape fabric, that will outlast the work of the romans lol. You should probably note that you are in Winipeg Manitoba and are preparing against serious frost and weather problems. Here that kind of prep is something they might only do on a commercial road application where large commercial trucks might drive on it, but likely not even a driveway and especially not a patio/walk.

 

since we are out of the same area I can fill you in a bit better. for a standard paver job you should have a minimum of a 12" excavation with 10" of back fill done in 3/4 crush gravel or "#57 stone" there should be a layer of woven geotextile under the first lift at a minimum but thats another story. the top layer should be done in concrete sand and the joints should be finished off with either poly sand or mortar sand. stone dust used to be widely used in the industry and still is but there are many reasons not to use it I will list a few here.
#1. Effloressence
#2. Holds moisture
#3. Breaks down to smaller fines
#4. It is not made of angular particulates so they do not bind well
So thats the basics of it #1 and #2 are tied to each other. it basicly comes down to the fact that stone dust is weak and has i very high fines content. the particles are flat chips VS. angular aggregate that you find in crete sand. I can keep going if you would like but it basicly boils down to the basics and having a really good base under your pavers.

 

I don't do pavers and rarely do flags but I do some. Any one ever use limestone screenings?

(In the voice of the lady from SNLs "Coffee Talk)
Discuss

 

im assuming lime screenings would be the same as stone dust. its usually the scraps from the crush plant.

 

Yeah, i just googled it and stone dust. same thing. Whoops.

 

I agree with working chump and 2lowforNH... millions of $ have been spent by institutions that study ICP basically to say that stone dust is not an appropriate material for the setting bed.
Aside from the major structural 4 points that 2low pointed out... most manufactures will not honor any warranty on their product if it is set over a stone dust setting bed.


Being just south of you in MA, ive noticed that many of the quarry yards dont have the correct base (crusher run, modified stone, etc). I asked a few for the gradation data (looking to meet ASTM-2940) and found that 'crusher run' from most suppliers did not meet the proper gradation. I found 1 quarry with the proper materials and also a reprocessed asphalt that meets the spec.