[VoodooChile]

In the numerous paver posts I've read plenty about "polymeric" sand, but have no experience with this product.

What exactly is polymeric sand, and more importantly, I'm wondering if it would be an effective top-dress for the joints on all the flagstone patios and paths I've been laying?

I set my flagstone on lime-pack (3/4" to fines), and fill the joints with the same, sweeping sand in after settling. Of course this is messy, and not easy on the feet.

Would polymeric sand set-up enough to keep the lime-pack in the cracks and the sand out of the house?

Are there problems with heaving, namely that over time the sand would settle out and the lime-pack surface?

How much does this stuff cost?

Thanks up front to all you paver guys!


Admin edit: This discussion has been included in the site beginner's polymeric sand page.

[scl]

What I've found is that with joints over say 1" it will tend to start flaking out after a year. I tried it with a large cobble walk and a flagstone path and that's what I've found.

Poly sand is a sand filler mixed with a polymer acrylide glue that while setting up andbecoming hard, also bonds to itself and the pavers and remains somewhat flexible so as not to crack up like mortar.

[diginahole]

I have found the same thing. Poly only seems to crust over a very thin layer and wide joints can easily be knocked loose. I wouldn't recomend it for flagstone, it's kinda pricey for only marginal benefit. I pay 20 bones a bag that does about a hundred sq ft of pavers.

[Pelican]

I tried the poly sand for the first time at my suppliers recommendation. You have to be extremely careful that your paving material is absolutely clean before wetting, or the sand will bond to your paver. I'm not sure how this will work out long term.

I have a lawn account where the brick pavers have the poly sand, and it is chunking out of the joints after about two years. I used a different brand that's supposed to be better, we'll see. From what I saw at my client's, I would think larger joints as you mention would chunk out sooner.

[Paul]

VoodooChile

Set your flagstone on the 3/4"- and use a mix of 1 part portland mixed with 6 parts limestone screenings in the joints, you shouldn't have any problems.

[VoodooChile]

Paul,
How would you recommend mixing the screenings and Portland?

I have a cement mixer I use for making potting soils, but I am guessing that would actually seperate the stone chips in the screenings from the lime dust and Portland...

Would a wheelbarrow and shovel be best?
Thanks!

[Paul]

VoodooChile

We use the wheelbarrow to mix in. just shovel in 3 parts limestone screenings first then the one part portland add in the balance of screenings. We use a hoe to mix with it's faster than a shovel. Sweep in the mixture dry. We don't bother to wet it down, seems mother nature makes it happen on it's own. You could use a hose with a fine mist just to sped up the process

[spiderlily]

One of VoodooChiles's patios:

[BJR]

You have to be very careful that portland cement doesn't stain your pavers. Especially concrete and dry pressed clay ones.

The idea of the polymeric sand is to be able to flex. You are creating a flexible pavement. If you try to have a rigid pavement, eg- pavers with a sand / cement joint, over a flexible base, the rigid pavement will fail. That is the sand / cement joint will crumble. If you want to grout your joints you have to wet lay the pavers or flagstone on a reinforced concrete base.

I laid a 4,500sq metre (approx 45,000 sq ft) mall using dry pressed clay pavers with sand / cement joints. This was the laying procedure the Designer wanted. The pavers stained badly, and the joints eventually crumbled. I never did it that way again.

As far as I know Polymeric sand is only suitable for tight joints in pavers. Say 1/8in.

[Terry D]

In CA, we use 4" concrete slabs. full blown mortar beds, and grouted joints. Lawsuits would happen if we did it any other way guaranteed.

If the stones are for informal gardens, dirt or garavel joints are fine, however this Poly sand seems like a quasi-flagstone job, so I'd simply fill the joints with a nice pami-pebble type stone (very colorful and smooth) 1/4" size and it doesn't track into the house.
It looks fantastic when wet and you'd be their hero!

Another option would be to fill with a panters mix and plant some Isotoma, Irish Moss or other creeping type groundcover.

[tfld]

We've always filled our patios with crusher fines ie "breeze" and sometimes, as Paul mentioned, with 1 part Portland.

The crusher fines set up semi hard, but when mixed with the portland, the joints become almost mortared. You just need to be careful to sweep all the portland off the flagstone before wetting. I've also noticed that the portland mix tends to dullen the color of the stone a bit before mother nature cleans it up.

Here is a patio we did this spring:

Flagstone Patio

Nick

[jraltwies]

poly sand usually has a mix of polyacrylamide in it...the same type of stuff used for erosion control and the base material for super absorbant. When it gets wet is swells into molecular spagetti, tying together the sand particles. It will break down over time by UV and microbes but should "re-heal" any cracks when it gets wet for long enough. I do some consulting for a group researching new uses for this sort of polymer and it has it's own unique issues...

[Stone Art, Inc.]

Techniseal recently created a new line of polysand specifically for larger joints. The only color its available in is the Charcoal Grey and it's called Techniseal HP (catchy, huh?)

Here's the link for the technical data sheet. We use the RG for paver joint sand, but prefer Epro Bond and Seal any day.

http://www.techniseal.com/tds/FT.SAN...-USA.ANG_2.pdf