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View Full Version : Compacting sand


forestfireguy
07-03-2007, 09:44 PM
I was watching a crew work next door to us the other day and saw something odd so I approached the foreman to ask. They screed the sand then run the compactor over it, then install pavers in the normal way and sand as ussual.. They showed me the results after the plate running over pavers, they seemed to bed just as well as if it had been done without precompacting the sand, the reason they do this is to avoid having to be as careful with the sand, they walked right over it without leaving even a footprint. Anybody do this?????? I know this isn't ICPI approved but it seemed to make sense, I just wonder if there are any long term effects of this.

McKeeLand
07-03-2007, 09:51 PM
this problem i see with that is that when you compact your paver into the sand it will not migrate as far between the joint, thus creating a weaker interlock.

cgland
07-03-2007, 10:33 PM
You will tend to get more horizontal migration due to the lack of interlock.

Chris

ChampionLS
07-03-2007, 11:41 PM
What they're doing is wasting time. When you screed sand, you leave a 1 inch (approximately) layer of sand on top of your base. I know people that are anal and think that if theres even a thumb print in the sand, the job will be messed up. NOT TRUE!. Sometimes there are jobs where you need to start in a corner and have no access. You must go across the sand. You could put a small strip of plywood over the sand and start laying that way, but a simple fact of Physics proves a inch of sand is a inch of sand. If you were to step right on the sand, and even walk back/forth many times, it's still an inch!. (as long as you dont kick it or mess it up). Also- Sand has round particles... like marbles. If the sand is compacted- either by foot or plate compactor, once you lay the pavers over it and re-tamp, the harmonic frequency will turn the sand to liquid, so it will still even out and flow up into your joints. It's a fail proof cushion. This is the reason for not using screenings. Stone dust/screenings will not "liquefy" under the vibration of the compactor and just pack down harder. This can be beneficial if your skilled at troweling or have a problem area that needs a little stiffening, but for the average job, always use concrete sand and dont tamp before. No reason for it.

AztlanLC
07-04-2007, 10:33 PM
Couple of guys I know use this method and swear by, me based on personal and ICPI instructions don't see any benefit but if it works for you why not use it, I really don't agree 100% with ICPI claiming not interlocking will be achieved if sand is pre-compacted I think is the same result if you sweep the sand from the top and make sure it gets into those joints by compacting real good, as a matter of fact I don't use sand anymore or stonedust, we use 1/4" gravel for the bedding base with real good results.

cgland
07-05-2007, 06:14 AM
What they're doing is wasting time. When you screed sand, you leave a 1 inch (approximately) layer of sand on top of your base. I know people that are anal and think that if theres even a thumb print in the sand, the job will be messed up. NOT TRUE!. Sometimes there are jobs where you need to start in a corner and have no access. You must go across the sand. You could put a small strip of plywood over the sand and start laying that way, but a simple fact of Physics proves a inch of sand is a inch of sand. If you were to step right on the sand, and even walk back/forth many times, it's still an inch!. (as long as you dont kick it or mess it up). Also- Sand has round particles... like marbles. If the sand is compacted- either by foot or plate compactor, once you lay the pavers over it and re-tamp, the harmonic frequency will turn the sand to liquid, so it will still even out and flow up into your joints. It's a fail proof cushion. This is the reason for not using screenings. Stone dust/screenings will not "liquefy" under the vibration of the compactor and just pack down harder. This can be beneficial if your skilled at troweling or have a problem area that needs a little stiffening, but for the average job, always use concrete sand and dont tamp before. No reason for it.


You're kidding right? Please tell me you are kidding! First, washed concrete sand has angular particles...masonry or any other improper sand has round particles. Never use a soil w/ round particles. Second, Sand NEVER liquifies when compacted....who told you this?:dizzy: The vibration settles the paver into the UNCOMPACTED sand. If your sand is precompacted it WILL NOT move into the joints and your pavers will most likely suffer from horizontal migration. Thirdly, you are saying that an inch of sand is still an inch even when you step on it. NOT TRUE! sand compacts just like any other soil. When you compact you are eliminating air molecules and pockets from the soil you are using...thus you are turning an inch of fluffy, air filled sand into 5/8" of fully compacted, airless sand. There are many more things that I could hammer you on, but I'm getting a headache from thinking about contractors like you. No wonder your jobs fail.

Chris

cgland
07-05-2007, 06:14 AM
Couple of guys I know use this method and swear by, me based on personal and ICPI instructions don't see any benefit but if it works for you why not use it, I really don't agree 100% with ICPI claiming not interlocking will be achieved if sand is pre-compacted I think is the same result if you sweep the sand from the top and make sure it gets into those joints by compacting real good, as a matter of fact I don't use sand anymore or stonedust, we use 1/4" gravel for the bedding base with real good results.

You're just as bad!

Chris

Tim Wright
07-05-2007, 09:20 AM
Hey Chris, How's it going?

Ready for another breakfast when things slow down?

Tim

cgland
07-05-2007, 06:02 PM
Absolutely Tim! You name it, I'm there! BTW, things never slow down! LOL!

Chris

mrusk
07-05-2007, 06:19 PM
I think i am finally ready for a lawnsite get to gether. Someone needs to have a BBQ at their house!

PatriotLandscape
07-05-2007, 10:37 PM
I love hearing how engineers are stupid and contractors know because they are in the field. Most of the guys who have not had serious issues is because there work has yet to stand the test of time sure a patio will be great week one, month one, year one. Go back year 5 and 10 then you get your real answers.

Don't compact your sand it is a waste of time because your not installing it correctly.

Sand is round? what beaches do you go to?

zedosix
07-06-2007, 09:40 PM
I think i am finally ready for a lawnsite get to gether. Someone needs to have a BBQ at their house!

Well good timing, I just bought a nice cast iron weber this evening. Come on up to Canada and have a real beer!:canadaflag:

dchauling
07-07-2007, 01:42 AM
How far east are you in ON?

ChampionLS
07-07-2007, 02:18 AM
You're kidding right? Please tell me you are kidding! First, washed concrete sand has angular particles...masonry or any other improper sand has round particles. Never use a soil w/ round particles. Second, Sand NEVER liquefies when compacted....who told you this?:dizzy: The vibration settles the paver into the UNCOMPACTED sand. If your sand is precompacted it WILL NOT move into the joints and your pavers will most likely suffer from horizontal migration. Thirdly, you are saying that an inch of sand is still an inch even when you step on it. NOT TRUE! sand compacts just like any other soil. When you compact you are eliminating air molecules and pockets from the soil you are using...thus you are turning an inch of fluffy, air filled sand into 5/8" of fully compacted, airless sand. There are many more things that I could hammer you on, but I'm getting a headache from thinking about contractors like you. No wonder your jobs fail.

Chris

For a contractor that's supposed to be professional in the industry, you certainly don't know more than the average homeowner. Do you even know why sand is recommended for the bedding layer?? Because it is a fail-proof layer in most circumstances to achieve a even, level surface. The sand, under the harmonic vibrations will "liquefy" AKA- smooth out and compress evenly, provided there are rigid edge restraints. If the edge restraints fail, YES the sand will keep forcing out with continued vertical force. Its obvious to anyone in the trade reading this what happens while walking behind a plate compactor.

Even if someone tamped the sand prior to placement, Once the pavers are compacted afterwards, the sand will still be forced up into the joints. That little bit of interlock (1/4-3/8") is not going to stop a driveway from migrating horizontally. The laying pattern dictates the degree of interlock by intersecting bond lines.

I hate to dampen your optimism, but unfortunately you are wrong again. Sand does not compact- it will only compress when bound on all sides. Somebody show me compacted sand!- Anyone. I wanna see you make a snowball from sand. Lets see you push a shopping cart through plate tamped sand. It will not hold together. Round Particles! Would you like to explain to our professional community how if you screeded one inch of sand, and it suddenly vanishes to some other number by simply walking on it? Perhaps you failed Physics in school? Or did you not get that far? The sand can be there 10 minutes, 10 days or 10 years. Wet, dry, hot, cold etc. etc. An inch is an inch PERIOD. You can lay pavers over pre-tamped sand, sand with footprints in it, dry soft sand, or damp sand. It's still an inch and after the final tamping the results will still be the same. :drinkup:

ChampionLS
07-07-2007, 02:35 AM
Quote:
Originally Posted by AztlanLC
Couple of guys I know use this method and swear by, me based on personal and ICPI instructions don't see any benefit but if it works for you why not use it, I really don't agree 100% with ICPI claiming not interlocking will be achieved if sand is pre-compacted I think is the same result if you sweep the sand from the top and make sure it gets into those joints by compacting real good, as a matter of fact I don't use sand anymore or stonedust, we use 1/4" gravel for the bedding base with real good results.


You're just as bad!

Chris

AztlanLC is correct. Sweeping sand over the pavers and compacting not only achieves equal interlock, it also helps provide a protective cushion for the plate tamper to glide across the paver's surface and protect it from scuffing.

Laying the pavers on 1/4 Aggregate is acceptable for permeable pavements and storm water management. Chris, do us a favor... put your hands around your neck and choke yourself. :dizzy:

ChampionLS
07-07-2007, 02:45 AM
WHERES THE INTERLOCK??

Great pattern! Oh wait.. the sand must have squished up into the joints. My bad.

photo compliments of CGLAND

sheshovel
07-07-2007, 03:42 AM
This is a very interesting debate for sure. Is it possible that you both are correct in certain aspects of it and you both are incorrect in certain aspect of it as well?
I say this calls for a sand off!

hoskm01
07-07-2007, 05:48 AM
I agree on the sand off...

I dont compact sand before laying, but I can see the argument that it may not make a difference. You cant really compact sand, lest you wet it, then thats a whole other story.

zedosix
07-07-2007, 08:23 AM
How far east are you in ON?

I see quebec "far east"

DVS Hardscaper
07-07-2007, 09:16 AM
I wanna see you make a snowball from sand.


Sorry, but I'd like to see you make a "snowball" from anything other than SNOW! :hammerhead:

heck, i'd like to see you make a *ball* from crusher run. Being we all have a digital camera now-a-days - we await a photo of crusher run formed into a ball :)


I do not believe in tamping sand. Never have. never will.

Sand is for bedding purposes only. Hence the term "bedding sand".

We screed one inch. no more, no less. This way after the pavers are compacted, they are settled in by 1/2 an inch.

ChampionLS
07-07-2007, 11:37 AM
A sand-off it is! ;)

Just don't get sand in your bed. Hehehe. :hammerhead:

When is the BBQ at Zedosix's? I'm getting hungry. :drinkup:

zedosix
07-07-2007, 11:49 AM
Sorry, but I'd like to see you make a "snowball" from anything other than SNOW! :hammerhead:

heck, i'd like to see you make a *ball* from crusher run. Being we all have a digital camera now-a-days - we await a photo of crusher run formed into a ball :)


I do not believe in tamping sand. Never have. never will.

Sand is for bedding purposes only. Hence the term "bedding sand".

We screed one inch. no more, no less. This way after the pavers are compacted, they are settled in by 1/2 an inch.


Your pavers settle by 1/2"... wow. Where does all that sand go if sand doesn't compact.

DVS Hardscaper
07-07-2007, 01:33 PM
Your pavers settle by 1/2"... wow. Where does all that sand go if sand doesn't compact.

EXACTLY!

- When we excavate, for pedestrian use, we excavate 8-inches.

- 5-inches for the aggregate base

- 1 -inch of bedding sand

- 2 3/8-inch for the thickness of pavers.

Add up those numbers and you'll get 8 3/8".

yet, when it's all said and done.......the pavement SOMEHOW is perfectly flush with the intended final elevation!

How does this happen???? :dancing:

Maybe we're just using sub-par pavers and the paver units theirselves are compressing.....as WE ALL know - the sand doesn't compact :hammerhead:



Anyone here ever been to Florida? Anyone ever seen all those buildings constructed at the edge of the ocean? Anyone ever notice that the soil there in FL is sand?? If sand doesn't compact - then how the hell are all those buildings not falling to one side?

I was at a seminar years ago. And there was an engineer speaking. ICPI seminar, if I'm not mistaken. And the engineer said "sand will compact just as well as aggregate, but the reason it is not used for a base is because sand is too expensive, aggregate is cheaper and aggregate will compact as well.

forestfireguy
07-07-2007, 04:02 PM
I didn't mean to start a fight, JEEZZZZ, but it is always interesting to see who has what to say........I see the merits of compacting the sand in ease of install, again if I saw the patio in 5 years and it looked as good then as it does now I'd probably do it myslef, it really does simplfy things but for now....I guess the jury is still out on this one. Sand in your bed sounds like it might hurt...,...LOL.....I like the idea of a BBQ, I think Matt volunteered since it is his idea. Maybe we could get Lawnsite to contact some of the sponsors to see if they are into doing a mini expo sort of thing, I have a good connection at one of the ski resorts here in Jersey.......

DVS Hardscaper
07-07-2007, 04:44 PM
.....I have a good connection at one of the ski resorts here in Jersey.......

For some reason a meet in NEW JERSEY just does not sound very appealing to me.

the meet, sure.

new jersey?? Yuck.

mrusk
07-07-2007, 05:37 PM
NJ is a good place to make $$$$

Mike33
07-07-2007, 10:15 PM
Tony Soprano did well.:laugh:
Mike

ChampionLS
07-08-2007, 03:01 AM
Anyone here ever been to Florida? Anyone ever seen all those buildings constructed at the edge of the ocean? Anyone ever notice that the soil there in FL is sand?? If sand doesn't compact - then how the hell are all those buildings not falling to one side?

I was at a seminar years ago. And there was an engineer speaking. ICPI seminar, if I'm not mistaken. And the engineer said "sand will compact just as well as aggregate, but the reason it is not used for a base is because sand is too expensive, aggregate is cheaper and aggregate will compact as well.


LOL do you really think buildings are built on sand? There are pillars or pilings that are driven down to bedrock. Even if Florida is mostly sand, there is still bedrock present for which these pilings are driven down into.

The ICPI would never suggest to substitute one material over another based upon price. They are not a financial adviser. It's all based upon A.S.T.M. (American Society for Testing and Materials) specifications. Sand and/or aggregate is not always present in every part of North America, and by following A.S.T.M. guidelines an equal substitute may be used. For example, on a big demolition job- They may have a crusher on site to recycle demolition concrete. The recycled concrete can be used as base material in a future parking lot or roadway.

sheshovel
07-08-2007, 05:05 AM
There are a lot of guys here that live in NJ. Seems like there many more of them lately anyway.

Stillwater
07-08-2007, 11:20 AM
This is pretty funny stuff, sand compacts, sand doesent compact, yes it does, no it doesen't..... oh my god.... one of you guys would be fired I won't say who though.

zedosix
07-08-2007, 11:36 AM
This is pretty funny stuff, sand compacts, sand doesent compact, yes it does, no it doesen't..... oh my god.... one of you guys would be fired I won't say who though.

I think if you take an inch of sand and screed a board across it, yes it will compact, mostly because some of the sand is being forced up the brick joints. I imagine there is some degree of compacting (removing minute air pockets) etc but to compact it by 50% I find a bit hard to digest. Put me down for yes sand compacts.

bigviclbi
07-08-2007, 04:43 PM
Sand compacts, but not alot. Where I live all houses on the shore are on pilings, the pilings DO NOT GO to bedrock. There is no bedrock. Here all the companies around me compact the sand. I don't know but I don't think its a big a deal. What they do is compact the sand then screed the top so that the small imperfections in the base are forgiven but the top of the sand is still soft enough that the sand compacts under the pavers when the pavers are tamped. I hear the argument that the base is the final level of the pavers, but I've seen this done enough to know that the compacted sand isn't going anywhere. Still I would suggest doing it by ICPI standards so that when we give prices out people don't realize why we are so high.

Drafto
07-09-2007, 10:03 PM
I really can't belive this arguement is going on? If there are guidelines for compressive strength, specs for gradation of modified, specs for welding, codes to follow, specs for shear pins, specs specs specs that are followed everyday in every workplace..........why are we arguing about ICPI specs? Has anyone ever asked an engineer why we should not compact the sand? Is anyone on here an engineer?

Follow the specs and the guidelines and you won't have a problem. Shortcut them, and I assure you'll have issues.

There has been a spec out for about 6 years (atleast) for overdig areas around new construction. In case no one saw the memo, your work will fail in those areas if you don't follow it. So I would suggest you follow the ICPI specs for bedding sand and stop with the debate or your work WILL fail..................like the over dig you knew nothing about.

Dan

kootoomootoo
07-10-2007, 01:17 AM
I buy pre-compacted sand.*trucewhiteflag*

AztlanLC
07-10-2007, 01:19 AM
Sand does compact but I never saw any of my jobs when I used 1" of state approved concrete sand to compact by half inch, a 1/8" or even a 1/4" sounds more logical to me.
The real tread was about pre-compacting sand which honestly don't see any harm and if it works for them good not that I have ever done it.
The method we use I learned from a friend of mine that has being laying pavers for many years now and that guarantees their jobs 10years, I have also seeing many of his projects with 10+ years and they still look more than good.
Lateral movement by pre-compacting honestly don't believe it, unless sand would turn solid I don't see that to be true.
Get 3 4x4 sheet of plywood install sand and lay pavers on one the next install sand pre-compact and install pavers, now push the pavers from the side and see which ones have more resistance.
You can do the same for different laying patterns and you'll understand why some are recommend it more than others at least for a driveway.

forestfireguy
07-10-2007, 09:12 AM
I think I'm going to pat myself on the back for a good thread.......LOL. And to all of you who think NJ stinks...There are many parts that do, however the area I refer to is very nice, lots of open space and farm land, I'm sure Matt can verify this.......Scenic Sussex County, it's not all Newark in Jersey.

ChampionLS
07-10-2007, 11:38 AM
I think the message to convey about compacting sand is basically that it will compress and/or compact dense and tight, provided that:
1) It's constrained from moving in all directions.
2) It is not used a leveling pad for any type of structure or wall, because it can be easily washed out, causing failure.

For those of you that live near a beach, lake or ocean...think about what happens when your standing on that nice hard sand close to the water and a wave washes up past you. As the water recedes, you sink down each time. Sand may compact/compress, but it's round particle size allows it to easily wash out.

Drafto
07-10-2007, 03:33 PM
I think the message to convey about compacting sand is basically that it will compress and/or compact dense and tight, provided that:
1) It's constrained from moving in all directions.
2) It is not used a leveling pad for any type of structure or wall, because it can be easily washed out, causing failure.

For those of you that live near a beach, lake or ocean...think about what happens when your standing on that nice hard sand close to the water and a wave washes up past you. As the water recedes, you sink down each time. Sand may compact/compress, but it's round particle size allows it to easily wash out.

Beach sand is round, it is washed sand, it is supposed to be round. Concrete sand is angular, which packs tighly when compressed. We do not use beach sand under our pavers. I take that back, I do not use beach sand under my pavers, maybe you do. But the properties are night and day when you are talking about standing on the beach. Dig a very, very deep hole on the beach and you should find some angular sand, that is the sand that we use, not the washed sand that hits your feet. Do some research on google about sand and its properties, then do some research on concrete sand specs and gradation.

Dan

John Zaprala
07-10-2007, 05:28 PM
You beat me to the punch. Concrete (aka bedding sand) should be angular.
http://a9.ac-images.myspacecdn.com/images01/91/l_7def4926f83df56f20d7c12317732a68.jpg
funny how it's the first thing mentioned in that section huh?
I have a feeling the companies compacting their sand for speed and easier installs also cuts other corners. ex. 2" lifts for compacting 2A base, the right kind of sand and stone. ICPI put more money and research into these topics than anyone one of us. Why do they spend almost 4 hours in ICPI classes explaining soil characteristics and the importance of using the proper aggregrates for the job if it wasn't essential to a properly installed patio. I'm not one to start an argument, but bedding sand shouldn't be round, too fine, compacted or have too much moisture. These are simple guidelines to avoid problems.

Cedar Valley Landscapes
07-10-2007, 08:51 PM
Well i am glad to see another debate on tamping bedding sand. I thought the one we all had a couple months ago would be over but here we go again. Atleast it makes for good and (sometimes funny) converstation. And to everyone stay busy and good luck for the rest of the season.