TCA: What does the Tilt-Up industry need to know about green and sustainability?

McPherson: I think the industry needs to understand that Tilt-Up and all concrete construction can play a role in green building and achieving LEED building certification. I hear contractors saying all the time that there is nothing that Tilt-Up or concrete can contribute to LEED but that is not the case. While there would be no way to achieve a LEED certification by utilizing only the credits concrete can achieve, it certainly can be a big help in earning easy credits for the project.

TCA: Why and how is Tilt-Up a fit for LEED?

McPherson: Tilt-Up is able to achieve several credits under the LEED system. For example:

1. SS (Sustainable Sites) Credit 7.1 – “Heat Island Effect: Non-Roof” can be partially achieved by using a slag/ cement blend. Using slag/cement blend in the site hardscape will achieve a Solar Reflective Index (SRI) of more than 29. Slag must be used as straight cement or fly-ash/cement will not achieve an SRI of 29 or higher.
2. Many of the EA (Energy and Atmosphere) credits (Prerequisite 2 and Credit 1) can be helped by using insulated Tilt-Up panels as they apply to the amount of energy used and the overall efficiency of buildings. Obviously, by properly insulating a building (and not having the thermal voids that framing studs and masonry have), the overall energy efficiency is higher and the energy usage will be lower.
3. MR (Materials and Resources) Credits 4; 5 and 7 can also be achieved through the use Tilt-Up and other concrete construction. Some examples of how these credits can be achieved include:

• MR Credit 4 can readily be achieved by using fly ash (25 percent) or slag (50 percent) or a tri- blend mix using cement/slag/fly-ash. Fly-ash and slag are considered “pre-consumer” recycled materials. Just by the shear weights and costs of these materials, the user is well on the way to achieving this credit. This credit is calculated by determining the recycled content’s weight and then multiplied by the cost of the product to determine the recycled content’s value. Also, reinforcing steel in today’s market is generally between 90 to 100 percent recycled content. The use of Tilt-Up will greatly increase the amount of reinforcing steel used as compared to most other types of construction methods. Between the fly-ash and/or slag and the reinforcing steel on a Tilt-Up project, this is usually enough to achieve this credit.
• MR Credit 5 can also get a big help from concrete and reinforcing steel. This credit applies to “Regional Materials” i.e. materials that have been extracted, processed or manufactured within 500 miles from the project. Generally (but not always) both the course and fine aggregates fall into this category as does the cement, fly-ash and slag. Also, the reinforcing steel will generally fall into this category. This credit is based on the cost of the items that can be included in this category and as with all the other credits, due to the large portion of costs associated with the concrete and reinforcing steel in a Tilt-Up project, these items will really help out in this credit.
• MR Credit 7 can also be applied to a Tilt-Up building. This is using Certified Wood from an FSC (Forest Stewardship Council) certified manager. Although form lumber is not a permanent part of the structure, the USGBC will allow the wood to be included (on only one project; i.e. the same wood can not be counted toward another project) but all other temporary lumber used on the project must be counted also (sort of an all or nothing). On Tilt-Up buildings, this is acceptable because there are not really any other trades using large quantities of temporary lumber for scaffolding, etc. so the form lumber is the bulk of the lumber used on the project.