Constructing Energy-Efficient Office Buildings

Building a high-per­for­mance office building at com­pet­i­tive market costs

In 2013, Bautex started working with real estate developer Ironsight PSMT to design and construct an office building in San Marcos, Texas, that would serve as Bautex headquarters.

The goal for the project was to design a roughly 3,900 square foot office building that would sig­nif­i­cant­ly reduce energy con­sump­tion and improve indoor envi­ron­men­tal quality. This achieve­ment would be a stark contrast to most office buildings in the region built using tra­di­tion­al con­struc­tion materials.

Real Estate developer Ironsight PSMT con­struct­ed the building using Bautex Block — a light­weight building block made from indi­vid­ual beads of expanded poly­styrene (EPS) mixed with a pro­pri­etary cemen­ti­tious material. Bautex Blocks are stacked to form a wall, then filled with steel-rein­forced concrete to create a strong, insulated and energy efficient building shell.

The R‑14 con­tin­u­ous insu­la­tion provided by the Bautex Wall System exceeded building code require­ments and com­plete­ly elim­i­nat­ed thermal bridging through the exterior walls. This sig­nif­i­cant­ly reduced the amount of thermal energy passing through the walls in the hot-humid climate of Central Texas. In addition, the thermal mass or heat capacity of the concrete walls also sig­nif­i­cant­ly con­tributed to the reduction of heat load on the interior of the building.

Energy effi­cien­cy was also enhanced by the appli­ca­tion of a full-width stone veneer on the south-facing side of the building.

Other com­po­nents of the building envelope included:

  • Low‑E insulated windows with thermally-broken store­front frame;
  • Exterior doors that utilize a thermally-broken doorframe and Low‑E insulated glass;
  • Standing seam metal roof with a high Solar Reflectance Index (SRI) of 63;
  • Ten-inch thick, R‑38, open-cell spray foam insu­la­tion under roof deck; and
  • Bautex Air and Moisture Barrier, sprayed onto all exterior wall surfaces.

Ironsight PSMT succeeded in designing and con­struct­ing a high-per­form­ing office building at a com­pet­i­tive market cost. Energy con­sump­tion has proven to be sig­nif­i­cant­ly lower than other buildings in the region, and indoor comfort is outstanding.

Mon­i­tor­ing data shows the building is averaging less than $125 a month (1,250 kWh/​month) on average in heating and cooling costs. These savings, combined with the low cost to operate LED lighting, results in elec­tri­cal bills below $200 a month on average (2,000 kWh/​month).

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