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Green Building Materials

EDITOR’S NOTE:
This is the fourth article in the five-part 360Value Green Building Article Series, intended to inform insurance professionals about the growing green building trend and how it may affect insurers in the future. The 360Value team has a comprehensive understanding of green building techniques and is actively studying this emerging issue to define more clearly how to incorporate the various green building options into 360Value.

In this article, “Green Building Materials,” we will review many of the new common materials used in green building.

by Mike Fulton, Assistant Vice President, Xactware, and Rob Caron, Senior Construction Specialist, AIR Worldwide

Green building is about making the best use of resources during all stages of construction. By combining a system of components and materials that work in harmony with one another, the goal is to create an energy-efficient, water-saving structure with a low carbon footprint. While selecting the right materials is a large part of green building, choosing the best materials may not be obvious and will depend on the needs of the building owner.

What, if any, green certification is the owner seeking?
Is the owner concerned about lifetime energy use?
Is the carbon footprint of the construction process a factor that concerns the owner?

In addition to those considerations, budgetary constraints may require making tradeoffs.

There are organizations that certify material as meeting specific green standards. Building owners and insurers need to be cognizant of possible “greenwashing.” This is a term used to define products that claim to be green but, in reality, are only trying to profit from the green movement.

Those organizations offer and advertise products that don’t meet green specifications. It’s important to look for green logos such as EcoLogo™, BuildingGreen™, Energy Star™, Green Seal™, Green Label™, Green Label Plus™, or other nationally recognized certifying companies. However, not all green materials carry a green label or are part of a green rating system.

Notwithstanding the benefit of certification, the “green-ness” of materials can still be a matter of perspective. For example, when considering framing materials, a builder may face several choices: buy lumber with a managed-forest seal of approval and chain of custody, such as FSC (Forest Stewardship Council), that may have been shipped long distances or buy lumber from a local mill, harvested and milled within 500 miles of the project. It’s difficult to say which is greener, and the decision would depend on the objective of the builder.

Since it can be difficult to define whether a particular building material is green or not, here are some general principles to consider.

Typically, the best material for any job is the one that performs the best with respect to the green criteria of the owner. That will likely include the product’s longevity but may also include how well the material or product works with the rest of the building as a system, whether it contributes to reducing energy or water consumption, or if it helps to improve air quality.
If two materials perform the same and have roughly equal expected lifetimes, natural materials are generally preferable to man-made ones.
Local materials are generally preferred to ones that must be shipped long distances, but you should weigh each material case by case.
If the perfect material is extremely expensive, and the next-best material is relatively inexpensive, it might be “greener” to go with the second-best choice if it allows adding other green choices to the building.

Beyond those principles, the choice of materials depends on the criteria of the builder or owner. The rest of the article will discuss common materials used in green construction. Some are new and cutting-edge, while others have been used in construction for centuries.

The Framing and Building Structure

Wood is the most common material used in framing residential structures and offers several green variations.

A building is really nothing more than an enclosed space. To maintain an enclosed space that will not collapse, some structure must exist to counter the forces of gravity and the elements. Builders have traditionally met that function by using stone or a wooden frame. While wood is the most common residential building material, there are now greener versions of wood available, as well as several alternatives.

Wood — Two types of wood are gaining traction among green builders — engineered lumber and wood certified by the Forest Stewardship Council (FSC). Engineered wood is very common on both green and conventional homes. It uses wood scraps and smaller trees to produce framing that’s stronger than traditional sawn logs. Engineered wood allows the builder to use less wood per structure and make use of wood scraps that would otherwise go to waste. Where conventional sawn timbers are used, some green builders use wood that bears FSC approval, meaning wood harvested from a managed forest.
Structural insulated panels (SIPS) — SIPS are large panels (4' x 8' up to 24' x 8') typically constructed at a factory. They are composed of foam insulation sandwiched between two sheets of oriented strand board (OSB). You can consider SIPS green because of their superior insulation and air-sealing qualities, but they often must be set in place with a crane. SIPS construction is typically slightly more expensive than conventionally built structures.
Insulated concrete forms (ICF) — ICFs are essentially Legos® made from Styrofoam™. They stack together to create a permanent formwork for concrete, which is then poured to make the structure of the building. While concrete has a very high embodied energy relative to most building materials, many consider it a green material for its longevity and durability.
Straw bale — Although straw bale construction is rare, it’s gaining in popularity. Builders build these structures in a manner similar to a log home — simply stacking up a solid material. The buildings offer excellent insulation and sound-deadening properties. They are surprisingly resistant to fire due to the inability of air to flow through the straw bales.
Earthen structures — Builders build rammed-earth, adobe, and other earthen structures using perhaps the greenest building materials. Constructed from dirt, gravel, clay, and lime, and often harvested locally, these homes offer a durable and well-insulated building.

Insulation

Insulation is critical for any building. Whether the builder is trying to keep the heat out or in, the amount of insulation will indicate how resistant a building is to losing energy.

Fiberglass — Builders generally don’t consider fiberglass insulation a green material because it typically contains a toxic binding agent and is very energy-intensive to make. However, superinsulating a structure beyond building-code requirements is a fundamental principle of green building. Many green builders take advantage of the low cost and ease of installation to superinsulate and save money that they can use for other green features.
Cellulose — Made from recycled paper, cellulose is the second most common insulation material and is considered a very green choice when used properly. Also, it is relatively inexpensive, with costs similar to fiberglass.
Natural fiber (cotton, wool) — Cotton insulation is typically made from recycled cotton fibers formed into a batt, a preformed section of insulation sized to fit snugly in a framed cavity. Wool is an excellent insulator and a rapidly renewable resource. However, while it is commercially available, you can typically find it only in areas where wool is abundant.
Polyurethane — Expanding spray-on polyurethane foams are quickly becoming very popular. They offer the highest insulation value for a given thickness and, because of their expansion during installation, are excellent at eliminating air leakage.
Polystyrene and isocyanurate — These foams are typically installed as preformed sheets. Builders commonly use them to insulate below grade, such as beneath a slab, but also use them as exterior-mounted insulation in some applications.

Roofing

Slate and stone roofs are considered green since they are created with natural materials and have a long life span.

Keeping the weather out of a structure is not only key to making it a comfortable environment but is also critical to making it last. Like the variety of choices for other building components, there are now numerous ways to cover a building. The color of the material can also have an impact. Light colors are preferable for all types of roofing, as they reflect more energy away from the structure and thus reduce the cooling load.

Steel — Steel roofing (both panels and shingles) is an increasingly popular green choice because of its high recycled content and longevity.
Slate/stone — These natural materials are excellent green choices but are very expensive due to both material and labor considerations. While mining companies typically mine and ship natural materials long distances, they have a very long life.
Composites — Manufacturers often make composites from plastics and rubber, and they mimic the appearance of natural materials such as slate and wood. They have the advantage of being lighter than their natural counterparts. Composites are frequently made from recycled materials and so have a lower embodied energy than materials that must be mined.

Exterior Siding

Traditional wood siding is a good choice for green building, particularly when using reclaimed, recycled, or FSC-certified woods.

Like roofing, exterior siding helps provide the distinction between indoors and outdoors, but, unlike roofing, siding can play a significant role in the appearance of the structure.

Wood — Wood is a traditional siding choice and, when properly designed and detailed, remains a reliable green building choice. Reclaimed and recycled wood as well as FSC-certified woods are all popular choices with green builders.
Fiber cement — This material is made from wood, sand, and Portland cement. Fiber cement offers excellent durability and fire resistance and is less expensive than many common wood choices.
Composites — Composite materials such as plastics and vinyl are not inherently green materials, but some consider them green because of their long lifetime and low maintenance requirement.

Interior Finishes

Green builders and designers typically try to replace the more common synthetic materials used inside the structure with lower-impact natural materials.

Natural clay plaster — Natural clay plasters are a green alternative to the more common gypsum-based plasters.
Low/no-VOC (volatile organic compound) paints, stains, and coatings — Paints and stains are a common source of indoor air-quality issues due to the amount of harmful VOCs needed to keep them in a usable liquid form. VOCs spur the quick evaporation of liquids in paint to leave behind a solid film of color. Many manufacturers are now offering low- or no-VOC alternatives to address this environmental concern.
Natural fiber flooring — Whatever type of flooring is desired, there are green alternatives. Rugs and carpets are available in natural materials such as wool and cotton, while wood and other solid alternatives such as bamboo and cork offer high durability and/or sustainable harvesting methods.
Paperless drywall — Paperless drywall helps save on deforestation by eliminating the paper surface manufactured from trees.

Heating and Air Conditioning

The proper orientation of a building with respect to the sun and other design details can contribute significantly to minimizing the heating and cooling needs of a building. There are also nonconventional HVAC systems that can play a significant role in using less energy in any structure.

Geothermal — Heat pumps can provide heating and cooling to a building using a fraction of the energy of a conventional system. They work very much like a refrigerator — by using a compressor, evaporator, and condenser, heat can be moved. Heat pumps use the earth, ground water, or even the air as a source of heat, or a place to remove it, depending on the season.
Solar hot water — Solar water heating has been commercially available for decades for domestic hot water needs, but these systems can be used as the primary source of space heating as well when coupled with radiant flooring. By using radiant rather than convective heat transfer, the system can heat water to a lower temperature, which works very well with solar hot water systems.
Focus on high efficiency and proper sizing — Using the most efficient equipment available not only conserves energy but saves money as well. By properly matching the system to the building, you can avoid purchasing an unnecessarily large and expensive system.

Conclusion

As discussed at the beginning of the article, the “green-ness” of building materials is often a matter of perspective. Ultimate choices on what materials to use depend on the goals of the builder and owner. However, our overview of common green materials provides a good summary of the materials builders can use to rebuild properties to a green standard.

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Comments

The comments posted by our readers do not represent the opinions of ISO or the author.

From: James G Drawert
Comment: In this article, I was somewhat puzzled by the exclusion of brick as an exterior siding. Also, no mention was made of Hardy Plank which has become very popular in the southwest. It could be that you are including HP under the fiber cement category

From: Mike Fulton and Rob Caron
Comment: Hi Jim,

Thank you for your comment. We appreciate your interest in our green building article series. The intent of the article is to provide an indication of some common items that are considered green, rather than to list all possible items, which would be an exhaustive list.

To answer your specific questions, Hardy Plank is sometimes used to refer to products of the James Hardie Company, which among other products, manufactures fiber cement siding. Our goal is to reference product classifications in a generic sense rather than pinpoint any particular manufacturer.

You are correct that brick can be considered a green product. While there are several organizations that designate green status, the LEED organization, which appears to be at the forefront of the movement, provides green points for brick if it meets the following criteria: they are recycled, made from recycled material, or manufactured within 500 miles of structure.

It is interesting to note that, according to the Brick Industry Association (BIA), there are 83 brick manufactures operating 204 plants in the US. Today, plants are located in all but eleven states (AK, DE, HI, ID, MT, NH, NV, RI, SD, WI and WY). Therefore, unless a home is located in AK or HI, brick will meet the third certification criteria in many cases.

Please contact us if you have any additional questions or would like more information.

Best regards,
Mike Fulton and Rob Caron