by Rob Cox, November 10, 2012
Eco-Friendly Swimming pool decks
As a follow up to our popular article two years ago on the same topic, let's revisit the question of what makes an eco-friendly pool deck.
For swimming pool decks, the available materials are endless, but most will fall into two main categories. Concrete or Wood. Within each main category we have several types of materials that are used for pool decks.
The goal of this article is to discuss these materials to help you evaluate their relative impact on the environment.
- Broom finished, or Stamped Concrete
- Pavers, Block or Brick
- Natural stones like flagstone
- Pressure Treated Softwoods
- Tropical Hardwoods
- Composite lumber
You might be surprised to see concrete pool decks mentioned in an article about eco-friendly pool decks. Cement, and the materials used to make concrete, bricks and pavers are natural materials. Production of cement, the primary ingredient in concrete and block products consumes a lot of energy (6 million BTU's per ton). Cement production also generates carbon and sulfur dioxides.
Production: Concrete Mixing plants consume far less energy to mix the cement for bags or trucks.The energy needed to transport it to the job site is equivalent to other pool deck types.
Permeability: This type of deck scores the worst on permeability, or the ability of rain and nutrients to reach the soil. Pool decks can be constructed to allow for planter areas, and for management of run-off water to avoid erosion and increase absorption.
Performance: A well laid concrete pool deck can last many years, with good soil and good luck. The ability to recycle or repurpose concrete is good in most areas of the U.S.. In some areas, dumping of concrete is a problem. Concrete decks are generally much less slippery than some options below.
Production: Concrete pavers are made primarily of a very dry mix of cement, sand and aggregate, formed in molds to their finished shape. They consume an equal amount of energy, but use less water than delivered concrete. Bricks however, have clay as their main component, and use very little cement.
Permeability: Much higher than concrete decks, in that pavers allow water to seep between them, through the sand bed and gravel beds, and back into the earth. Many pavers recommend sealing, which if done poorly, can put bad chemicals into good soil.
Performance: Also higher than concrete decks, pavers are up to 4x stronger than delivered concrete, and individual pavers can be replaced. Recycling is possible at any landfill with concrete processing. Pavers are usually quite non-skid.
Production: Flagstone or Bluestone decks are milled from mining operations which use far less energy than concrete plants. If set onto a concrete base and mortared in between, the net gain of using stone is negated.
Permeability: If set on a base and mortared, the permability is poor. Installing stones on a bed of stone dust, with wide open joints will improve this, but is a less desirable finished surface.
Performance: Natural stones are the strongest in the category, and can last forever. Changing tastes however, won't last that long. Replaced natural deck stones can be recycled, or given a new purpose. Some stone finishes can be slippery, particularly if polished.
Wood is a natural material, and some manufacturers of Tropical hardwoods are fond of calling their product Eco-Wood, or something similar. If there truly is sustainable and responsible harvesting and replanting of the donor trees, and not simply clear cutting of old growth tropical rain forests, the claim may have some validity.
Pressure treated woods are usually soft woods like pine or fir that are treated with chemicals to resist rot, decay and make it taste awful to wood consuming insects. Arsenic is no longer used as the preservative, a copper quat compound is usually used, which gives this wood its green tint. The chemicals can be harmful if released during installation. A mask should be worn and sawdust should be swept up and disposed of properly.
Composite wood is a blend of wood, sometimes reclaimed waste wood - and plastic materials, sometimes post-consumer. This material can mimic wood grain, and outlast real wood. Because it's a blend however, it cannot usually be recycled.
Permability is high on all of these types of deck materials, assuming that they are built off of the ground, with nail width spaces between.
Wood can sometimes be slippery when wet or dirty, and some composite lumber is known to be even more slippery when wet.
Production: Sustainably produced fir or pine wood is treated with preservatives and then put through high pressure chambers to push the chemicals deep into the wood. From the sustainably managed forest, to the mill and then to pressure treatment, energy use is considerable, although much lower than concrete products.
Performance: Pressure treated wood certainly outlasts un-pressure treated wood, but it does have a finite lifespan. Sealers can extend the useful life, but could be harmful to the environment and the organic sealers can require several treatments per year.
Production: Woods like Ipe, Curupay and Grapia harvested from South America and other tropical areas, and sent by ship or truck to areas that can afford it. Be wary of claims of sustainability from manufacturers. In some cases without a responsible plan for reforestation, displacement of wildlife, or the effects of erosion. A better option may be North American grown western cedar or redwood.
Performance: These tropical hardwoods resist most insects and are among the hardest, most durable wood on the planet. To keep them looking nice however, manufacturers recommend sealing, which can be harmful (unless done very cautiously and with organic stains) to the environment immediately beneath your deck, and in the watershed beyond.
Production: Look for the highest percentage of post-consumer content being used, for the largest eco-gain. Some manufacturers of composite wood offset their energy and resource needs by using reclaimed wood or sawdust and recycled plastics in their production.
Performance: Composite wood can outlast regular wood, but is subject to fading, stains, mildew or warping. Being a blend of wood and plastics, it's difficult to recycle or repurpose after replacement.
Unscientific Chart of Swimming Pool Deck Types and some Desirable Pool Deck Attributes
|Ease of Recycling||4||5||5||3||4||1|
|Low Maintenance Req'd||5||4||3||4||4||5|
|Low Chemicals Req'd||5||3||4||3||2||5|
|Low Production Resources Req'd||2||1||5||4||3||4|
All swimming pool decks have some impact on the environment. This somewhat arbitrary chart I created above seems to indicated that pavers and stones would be the best choice, but it depends on a few factors. Decide for yourself what would be the best swimming pool deck for your pool!
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