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).

Down­load the Com­plete Case Study.