Got Sand?

There are alot of paver joint sands available to consumers and contractors.

If you are considering a new paver patio or if it's time to re-sand an existing paver patio, here is some information to better educate on the differences of various sands out there.

Unfortunately, “polymeric sand” has become common terminology for stabilized joint sand around the country.

The main ways that paver joint sand can be stabilized include . . .

-       Acrylic sealer

-       Cement

-       Polymers

-       Organics

Mixing a small amount of cement powder with sand before filling the joints is not recommended or very common these days, mainly because of the staining issues.

Application of an acrylic sealer (aka coating-type sealer) to the paver surface will also soak down into the joints, binding the sand particles together. The higher the solid content in the sealer, the better the joint sand stabilization. But, if sealed too soon, can cause secondary efflorescence to be trapped. Also, acrylic sealers are not recommended on clay pavers and some types of natural stone. They need to “breathe” and acrylic sealers do not allow for that.

Polymers are water-soluble acrylic particles mixed into the joint sand and activated by water. When dry, the joint sand is hard & stabilized, similar to the results when applying an acrylic sealer, just without sealing the paver surface. This is polymeric joint sand.

Organics are ground-up plant products that are also mixed with the sand before filling joints and activated with water. When activated, the organic material swells and becomes gummy, binding the sand particles together. When dry, the joint is hard, but not as hard as some “polymeric” joint sands. Organics are also used in stabilized gravel paths and other applications outside of the paver industry.

Differences between Polymers & Organics: During activation, polymer stabilized joint sands need to be activated gently with several light misting of water. If activated quickly with too much water, the polymer washes away through the joint. Organics need to be activated one time with a thorough saturation. You don’t want to blast the sand out of the joint, but you also don’t want to mist it. Misting only activates the top and creates a scab, making it difficult to activate the rest of the joint.

Polymeric sand, once hard, does not have the ability to “heal”. Once the bond is broken (freeze/thaw, flexing of the pavement under load, etc.), that is it. Organics reactivate when reintroduced to water. Typically, only the very top of the joint reactivates, but with enough water, the entire joint will too.

In the case of concrete overlays (pavers laid directly on top of a concrete slab), polymers and organics can (not always) remain wet long enough to cause problems. Since drainage under the pavers is reduced, compared to sand set, the joint sand will remain wet longer than normal. In these cases, polymers can start to re-emulsify, allowing them to be washed away. Organics will start to deteriorate early and lose the ability to heal. In the case of non-typical pavers, such as the Belgard Mega-Arbel, the shallow false joints can present the same problem as concrete overlays to the polymers AND organics.

No matter what type of stabilized joint sand you are working with, none are designed to act or perform as a grout. You can reduce joint sand loss, but never eliminate it. All stabilized joint sands break down over time. But during that time, the silts from traffic and weather typically take over the sand binding. In fact, grout is too rigid and will fail on a flexible pavement over time as well.

Flexible pavements are just that, flexible. They are far superior to other pavements (poured concrete, asphalt, etc.) but present their own maintenance issues (joint sand washout and replacement over time being one of them). Normally, with a standard joint, just using a proper joint sand that has a good mix of particle sizes ranging from the #4 Sieve down to the #200 Sieve provides great interlock with the walls of the pavers and helps reduce loss. But with many of the manufacturers offering product lines that have wide and/or false joints, the joint sand challenge is more difficult.

Never power or pressure wash a paver patio. In some cases this will void out the warranty. 

  http://www.classicgardencreations.com/

Charity Begins at Home

Here in Portland that is.
If you have some free time this summer to support a local charity either by volunteering or to make a donation, the Audubon Society of Portland has received Charity Navigator's four star rating, the highest rating awarded!

Charity Navigator is an independent charity evaluator, who rates charities by evaluating two broad areas of financial health: organizertional efficiency and organizational capacity. After careful scrutiny, they issue an overall rating that combines the charity's performance in both areas.

Charity Navigator provides these ratings so donors can make informed giving decisions,showing "how efficiently a charity will use their support today and to what extent the charities are growing their programs and services over time. You can read more at CharityNavigator.org.

The Audubon Society of Portland is honored to have 12,000 plus members who generously give their time and their money. You can be rest assured   that they will use your donations well!

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