Friday, May 11, 2012

Energy Efficient Building Envelopes

With many areas having adopted the 2009 International Energy Conservation Code, there are new considerations being evaluated in wall construction. Many climates are required to have a layer of continuous insulation in their exterior walls to meet this code. If your schools are constructed using either metal studs or masonry, the insulation between the studs or in the cells of the masonry is not considered continuous and an additional layer must be added outside of this wall.

An alternative wall system gaining traction in some areas is ICF - Insulated Concrete Forms. This wall system uses two layers of foam that work both as the formwork for a concrete wall and for the layer of continuous insulation. The foam forms can easily be cut to place electrical conduit or small pipes. A masonry veneer can still be applied to the exterior face of the wall. The most common interior finish is gypsum board.

There are several benefits to this wall system. It has a higher R-value than other standard wall systems, thus making the envelope more energy efficient. It is also much faster to construct, which saves time and money during construction. ICF is also designed to be a load-bearing system, which eliminates the need for any structural beams and columns around the perimeter of the building, also a direct cost savings. A disadvantage of this system is the increased wall thickness, which is typically 1'-6". This increased wall thickness translates into a larger building footprint. However, even with this increase, the cost savings generated by the benefits listed above result in this wall system still being very comparable in $/SF to a masonry wall system.

5 comments:

  1. Melissa Bryan, Tarleton State UniversityJune 20, 2012 at 4:47 PM

    Aubrey,

    Great information, makes me wonder why any school district building a new building wouldn't seriously consider these types of walls. Do you know approximately how many buildings have been constructed utilizing this design?

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  2. Good information. My little district recently contracted services for the completion of an energy audit. One of our buildings is very old and energy inefficient. According to the projected costs savings, we could save $12,763 annually on utilities by investing in the envelope. This savings is just under the $25,982 expected utilities savings by upgrading to energy efficient lighting!

    Lindsay Morgan, TSU

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    Replies
    1. Another disadvantage to insulated concrete forms (ICF) is if there is future plans to make any changes in the structure of the construction or move any walls it will take longer and cost a little more. Concrete cutting tools are required to make any changes to this type of construction. Labor cost may also be affected, as this can take more time than traditional renovations.

      A great advantage to using ICF is the sound absorption for ICF is better than frame built walls.

      A. Agunbiade, TSU

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  3. This information is interesting. I had not heard of ICF walls before and after reading the blog I am intrigued. I agree why are more schools not considering this when they build? I did look online and found that ICF walls are not a new unknown method of construction and there is a great deal of information about the amount of enegry they save and the advantages of choosing an IFC wall.

    Leslie Mills TSU

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  4. Sounds like a worthy update in technique to me. Though the larger footprint may be an disadvantage to some, I think the the savings down the road would be well worth it.

    M Nelson (TSU)

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