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View Full Version : Pavers... Compact Sand or not


heygrassman
09-08-2002, 09:00 AM
Quick question that searching did not help find the answer to..

When installing pavers and after a good sub-base of crushed limestone is compacted, do you compact your sand as well??

TIA,

Jeff

mike48114
09-08-2002, 10:26 AM
For pavers that will see foot trafic only you should use 4" of compacted base and 1" of NOT compacted sand. If the paved area will see car or truck trafic, you will need at least 6" of base and the same 1" of NOT compacted sand.

I recomend using Slag Sand, but there are others you may use.

Also...Dont forget your jointing sand!

RwADesigner
09-08-2002, 11:23 AM
Yea you dont ever compact the sand.

Just the sub base

Concrete sand is great for your sand layer

Stonehenge
09-08-2002, 01:58 PM
Mike, slag sand used to be the base mat'l of choice when I was in MI 12+ years ago, and may still be. However, it can have so many hazardous materials in it (like lead and cadmium), and unless you are frequently asking for EPA test reports to see what the levels are, you have no idea what you may be subjecting your clients to. Not to mention, the size of the particles is a little on the small side. Slag sand (foundry sand) is not a viable base material in many markets.


Run a search on 'patio base' and you'll find a very in-depth discussion on this topic.

As for the sand, you don't compact it. At least not directly. Once you've laid and cut in your pavers and installed edge restraint, then compact the pavers (thereby compacting the sand, indirectly).

Guido
09-08-2002, 07:35 PM
Originally posted by Stonehenge
As for the sand, you don't compact it. At least not directly. Once you've laid and cut in your pavers and installed edge restraint, then compact the pavers (thereby compacting the sand, indirectly).

Exactly.

And that Patio Base thread is a real good one if I'm thinking of the same one. It was a while back.

One thing I don't remember if we hashed out or not was this.

When compacting the pavers, I've seen it done two ways. I've seen the paver being compacted and then the joint sand added, and I've seen the joint sand added and then compacted. What are you guys doing?

I seem to have better luck with the joint sand first, and then compacting. It seems to keep my joints a little bit mroe even and the vibe helps get that sand down in the joints really good.

After that I sprinkle some water on it, rub it in with a broom and let it dry. If I can, I usually leave the sand on there for a little bit just to let it fill in, and then come sweep the excess off. I'm lucky to be able to do this because of where I'm doing the work. I'm sure you guys might have trouble leaving a job like this for a paying customer.

Anyway.....how do you guys finish once the pavers are cut and laid?

steveair
09-08-2002, 08:13 PM
Haven't seen you around these parts for awhile guido, welcome back!

I always sand and compact....can't imagine doing it any other way. I usually sand, compact, sand again, and compact again, then sand for a third and final time....that way you really work the sand in. The first two sandings are done very quickly, and the third is done slower to make sure all joints are filled.

Also, I think it is critical to sand before compaction because the paver joints will be thrown off, especially around the edges where the cuts are....are the smaller pieces need something to lock them in during compaction or they move around get twisted around.

steve

Guido
09-08-2002, 08:28 PM
Glad I'm not lonely on this one! I know you Paul, Lanelle, and Stonehenge probobly remember me whining about getting these guys in Germany to give up some of their old school ways and let me bring some new ideas out. This was one of them. One of the civillians thought I was an idiot when I started spreading sand before we compacted.....he was hootin and hollerin......

Funny though......all those guys that laughed at me when I would show them the way I learned how, all do it my way now.......by choice of course.

I wish I had more time to post this year....Its been a rough year over here. I spent about 5 months in the 'Stans playing in the worlds biggest sand box, and all the humanitarian aid we were running out of here, and all kinds of fun stuff we built (that I can't talk about on here (boy do I sound important!:rolleyes: )), and a winter that got dumped on us when we really weren't ready equipment or manpower wise.
Anyway, its been busy. Hopefully this will be an un-eventful year and I can spend some time cruising the forums.

See you around!

Stonehenge
09-08-2002, 10:48 PM
We've started using polymeric sand more and more with our installs - the only thing that really changes in the install process is to be extra diligent about cleaning sand off the pavers, and then wetting down the polymeric sand so it hardens up. But the compacting and sweeping chronology is the same as you.

Lanelle
09-08-2002, 10:54 PM
Never compact your bedding sand prior to laying the pavers. Don't even let a guy walk through it. After the pavers are down, sand the joints and compact. Sweep in the joint sand again to really fill the joints. The interlock is gained by forcing sand up from the bed and down from the sweeping. The compactor does that forcing. The bedding sand should be washed concrete sand.

Lanelle
09-08-2002, 10:58 PM
Hey Jeff,
Glad to see that you are using sand nowadays.;)

SCL
09-08-2002, 11:38 PM
Lanelle beat me to the punch on the sand thing, sorry Stone. All we use now for jointing is polymeric. Great stuff and a great selling point. Went to the Flower show in Chicago last year and a guy was giving a seminar on pavers. He starts out by saying to compact the sand. I know better. Just float it and keep it fresh.

Guido, do you still make your newbies compact sand?:p Thanks for making the world a safer place for landscaping.

Stonehenge
09-09-2002, 09:11 PM
Naw, not by choice!

We've used bedding sand on enough installs to be familiar with the process, but those are installs where we don't have access to our usual materials.

When we do, it's all stone all the time, baby! (except the joint sand, of course)

neighborguy
09-18-2002, 08:08 PM
How thick does everyone screed their sand layer?

We screed ours to about a half inch or less. While screeding we use a masons trowel (14" rectangular) and lightly compress the sand with that. we then lay our pavers and do not run the compactor over most jobs. We only use the compactor over concrete pavers because we get too many broken and chipped clay pavers.

What exactly is polymeric sand? We use a mixture of silica sand and portland cement on our concrete pavers and silica sand only on our clay pavers.

just more fuel for the debate.

heygrassman
09-18-2002, 09:03 PM
Unilock recommends 1" not to exceed 1.5"

http://www.unilock.com/installationinfo/basicpaver/2a.html

Stonehenge
09-18-2002, 09:08 PM
Neighborguy - stop using portland - it does not leave you with flexible joints. Polymeric sand has polymers in the sand that harden (not like cement) when wetted.

Always compact your pavers after laying them - otherwise, time and traffic will do it, leaving an undesired result.

Buy a urethane pad for your compactor - that will solve the chipping problem.

steveair
09-18-2002, 09:21 PM
A funny observation I thought of while reading the last few posts was all these large, mega jobs where they use machines to put pavers in......while they drop the layers in, they are driving all over the pavers with the 'cart' before they sand and compact.....

I'd imagine that on such large scale projects, more imperfections are allowed, but would think that driving the buggy all over non-compacted pavers would make for a wavy surface.

steve

paul
09-18-2002, 09:50 PM
Steveair, not really the paver setting machine stays back from the edge of the pavers so they don't move. The trick is getting close without going too far or too fast either one can cause you to lose your bond lines.

site
09-19-2002, 11:54 AM
What is the logic behind not compacting the last 1" lift before laying pavers? How do you know your heights are going to work out around steps,driveway edges, etc. ? What problems would you encounter if you were to compact fully first, then lay pavers, then compact again?

Lanelle
09-19-2002, 11:48 PM
The function that compacting the pavers accomplishes is to vibrate sand from the bottom up into the joints as well as down from the top. Wet, compacted sand isn't loose enough to move freely upward. The other problem is uneven compaction since sand moves. The plate will push it around especially on the turns so then you are laying on an uneven bed. Big problems.

site
09-20-2002, 11:08 PM
Thanks for your answer Lanelle, but I'm still wondering- what do I gain by laying pavers on 1" of uncompacted sand? What's wrong with laying pavers on a completely pre-compacted base Then compacting again. Won't the compactor set them just the same?

Lanelle
09-20-2002, 11:16 PM
1. Time
2. Consistent, predictable results.
3. More interlock of sand in the joints with is what locks the pavers in place.

site
09-20-2002, 11:26 PM
OK, I'll try it. I have been compacting the entire base forever, but I'm willing to evolve if necessary. Does anyone else lay clay brick just like pavers?

Stonehenge
09-20-2002, 11:56 PM
Site, don't let the dark side take you in........


Using sand will save you time, but when has quality ever come by going faster?

The consistent results - well, you have to make a leap of faith as to what the sand will compact down to, depending on the sand and it's moisture content. It will shift and move to eliminate flaws in the stone subbase, but there shouldn't be any flaws in it to begin with, right?

As for pushing the sand around - I agree, compacting on a sand course isn't a good idea. However, knowing that sand shifts and moves if compacted prior to paver laying, what arguement is there that the sand won't continue to move under traffic over the years?

Increased interlock? Maybe, but I haven't seen much empirical evidence of that.

I must be getting ready for an off season of debate....

site
09-21-2002, 10:37 PM
Stonehenge-
I'll work with you on the debate, but last year the season ended January tenth. We still have 3 months left.