# Using a Plate Compactor for stone patio



## MurphyMan

I am laying an irregular stone patio. You can see this thread for me previous work : http://www.diychatroom.com/f105/looking-methods-lay-stone-187841/

It seems to be best practice to use a plate compactor on the stone, to even everything up and flatten it out. I am a little concerned that the compactor will chip or scuff the stone. I think it's kind of a limestone, but I'm not sure.

I have looked all over for a plate compactor with the buffer pad. This photo is an example I found on the web. Does anyone know if I am risking my work if I don't use a pad? 

How about substitutions? Maybe there is some other locally available material I could use.

Thanks.


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## Daniel Holzman

I have done a fair amount of stone work, some very similar to yours. The most important thing is to have a properly prepared base. We set our stone in about 12 inches of masons sand, compacted in four inch lifts. We used a plate whacker to compact the sand, but we did not run over the stone (or the brick when we did a brick walkway), for just the reason you mentioned (do not want to damage the stone).

I did tap each stone into place using a 4 lb hand sledge with a pad under it, seemed to work fine. The stones (and the brick, which we did the same way) have not moved in 20 years. No doubt there are other ways to do this, but that method worked for us on several projects.


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## jomama45

You're stone are rather big compared to the average paving brick, and it looks like you'll have larger joints, so I wouldn't think running a plate compactor over it would be necessary. The biggest reason for using a plate over brick/pavers with smaller joints (1/8" to 1/4" typically) is to get the sand/poly sand material to settle into the bottom of the joints and to lock the brick tight. SHouldn't need that on joints the size of your's.

IF you still wanted to run the compactor over, I'd highly recommend the pad regardless of material. Some of the many alternatives to the rubber mat I've hear/seen through the years: Mud flap zip-tied to compactor, carpet remnants, full sheets of plywood laid out over patio, etc...


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## MurphyMan

The patio will be over well compacted cracked gravel, with approximately 1" of bedding sand. I imagine course sand would be better, this stuff is washed sand and is practically like water when dry. I hope that does't cause trouble down the line.

I will be using polymeric sand between the joints.

This morning I went over to our local Mack Truck dealer/shop looking for a mudflap. I found something even better. It's a large scrap of poly material used for heavy truck bed liners. About 3/8" thick and extremely tough. It should be easy to trim on my band saw, then bolt to the plate compactor. I'm attaching a photo of the stuff.

I'm going to and make a deal with the plate compactor rental guy. I'll trade him rental of the compactor, and in exchange, he can have the pad when I'm done. :yes:

My contractor, who did the gravel & sand for me, kind of messed up the slope and I'm going to have to add a bit more sand.


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## MurphyMan

I am afraid I have the wrong bedding sand. 

I found a good web site in England. One thing of note, they said we used the wrong bedding sand. My contractor brought in a washed sand, when we should have used a course sand. Also, they recommend mixing the sand with cement 10:1.

My washed sand flows like water when it's dry. The course sand would resist movement.

Here is the link: http://www.pavingexpert.com/layflag3.htm

So, I am faced with using it as-is, or having it scraped off and getting coarse sand. :furious:


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## Daniel Holzman

I don't see the problem with sand flowing like water when dry. Most sand does that. The thing that gives your sand strength is that it is confined, so it cannot flow anywhere. I would try out a few blocks, see how they set in the sand. My guess is it will be just fine, so long as you compact the sand first. To compact, you need to get the sand a little wet, then hit it with the plate whacker. As a test, you can compact a small area just fine using s sledge by dropping it onto the sand in four inch lifts. This gets old pretty quickly, but just to convince yourself that the sand you have will work, you can compact a small area, say a couple feet square, and put in a few blocks to see how it shakes out.

You can certainly use cement, but in my experience it is not necessary. I never have, and there have been no problems in 20 years. And I have used a wide variety of sand types, ranging from round sand grains to angular grains.

By the way, coarse sand refers to the size of the grains, and has nothing to do with the shape. Angular grains are typically stronger when compacted than round grains, but curiously the size of the grains is essentially irrelevant to the strength after compaction, strength depends on the angularity of the grains and the gradation of the sand (well graded mixes with a wide variety of sizes compact to a stronger sand than sand mixes with only one size). But this is a patio, not the Hoover Dam, so I would try it, have a beer, and relax.


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## stadry

when we did some of that work, we laid stone over a screed'd & plate-compacted granular base ( small crushed stone/stone dust ),,, the actual bedding was mason sand then we swept sand into the open jnts,,, since then polymeric sand's been developed - we'd use that today.

imo, sand isn't compactable :no:


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## beststriker21

You really need to compact or you will not have
a stable patio.


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## Bondo

beststriker21 said:


> You really need to compact or you will not have
> a stable patio.


Ayuh,.... This thread is 14 months old,....

I'd hope the project is long Done,....


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## MurphyMan

*This is how it turned out.*

We are very pleased with my first (and probably my last) shot at stonework.

I wish I had made it a bit wider, but it was a conscious decision based on the ease of mowing around it on the hill, my inexperience, etc.

But we love it and really enjoy having an evening beverage out there.


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## Doc Sheldon

Did you stay with the 1" of washed sand, MurphyMan, or did you end up adding more? 1" seemed like very little to me, but I was envisioning a more irregular under-surface on your stone, too.


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## MurphyMan

I'm not sure how thick the sand wound up, probably four or five inches in some places, less in others. I thoroughly compacted the sand before setting the stone in place.

All the stones were a different thickness. This caused me to raise and lower each one several times until it was level with the others. Some of those rascals weighed over 80 pounds, so it was a tough job. I would add or subtract sand as needed then tamp it in place with a dead blow hammer.

When the setting was done I ran the plate compactor over the whole thing. I then added Gator polymeric sand and compacted it all again.

BTW, I had originally started out by leveling each stone, from one end to the other. Fortunately, I ran into a guy who was using the same stuff, just a few blocks away. His big tip was to first lay out all the stone on the sand, then come back to level it all. I think that was very good advice. I laid a sheet of plastic on the ground then de-palletized the stone so I could see what I had. Worked out well for this beginner.

In these photos you can see how uneven it was before I went back and re-leveled.


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## mikegp

Very nice. How exactly do you re-level the stones. Just pick it up and add/remove sand? Or maybe there's an easier way. That sounds like an awful lot of work.


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## Canarywood1

And for anyone planning on doing this in the future, you want to use #2 torpedo sand for the base of your stone or pavers, it's a coarse sand ideal for the job and compaction.


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## MurphyMan

mikegp said:


> Very nice. How exactly do you re-level the stones. Just pick it up and add/remove sand? Or maybe there's an easier way. That sounds like an awful lot of work.


Yep. Awful job. I have no doubt that an experienced stone guy would have a better way. Maybe I didn't have to be so anal about it and just rely on the compactor to do the job. At any rate, it turned out great.

Builders tip: Pay attention when swinging the mallet. :hammer:


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## beststriker21

MurphyMan said:


> Yep. Awful job. I have no doubt that an experienced stone guy would have a better way. Maybe I didn't have to be so anal about it and just rely on the compactor to do the job. At any rate, it turned out great.
> 
> Builders tip: Pay attention when swinging the mallet. :hammer:


This is not a good stone you should use granite stone in granite setts measure for this.


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## MurphyMan

beststriker21 said:


> This is not a good stone you should use granite stone in granite setts measure for this.


Yes, that looks like nice stone, but you have to deal with what is available locally.


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## beststriker21

the price between each other is not very different even with transport included.


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