Government

Updating Traditional Building Systems Are Not Enough for Today’s Schools

Modifying existing building systems is a difficult, costly compromise

School dis­tricts are ask­ing much more from new school build­ings than ever before. Build­ing codes are also requir­ing bet­ter per­for­mance with respect to ener­gy effi­cien­cy and life safe­ty. The nat­ur­al response to these new cri­te­ria has been to mod­i­fy the tra­di­tion­al build­ing sys­tem in order to pro­vide the addi­tion­al per­for­mance required. The archi­tec­ture-engi­neer­ing-con­struc­tion indus­try has found it eas­i­er to sim­ply stick with what they have always done and attempt to make mod­i­fi­ca­tions to meet the new, high­ly evolved per­for­mance goals.

For wall sys­tems in par­tic­u­lar, this has meant adding mul­ti­ple lay­ers of mate­ri­als to meet each of the indi­vid­ual objec­tives. The two most com­mon wall sys­tems used in the con­struc­tion of school build­ings have been con­crete mason­ry and struc­tur­al steel with light-gauge fram­ing. The chal­lenge for these sys­tems has been address­ing the insu­la­tion and air tight­ness required to meet the new ener­gy effi­cien­cy goals, while also avoid­ing fire and life-safe­ty con­cerns intro­duced by the addi­tion­al insu­lat­ing and air bar­ri­er mate­ri­als.

Adding lay­ers to either of these tra­di­tion­al sys­tems has intro­duced more com­plex­i­ty in design­ing the details of a wall sys­tem, espe­cial­ly at win­dow and door open­ings, con­nec­tions to oth­er build­ing ele­ments, and inte­gra­tion with exte­ri­or fin­ish­es. These more com­plex designs have also increased the amount of time and mon­ey it takes to con­struct a school build­ing.

More lay­ers of mate­r­i­al means more trades on a job site, more coor­di­na­tion issues as each trade attempts to accom­plish their scope of work, and more labor required over­all to get the job done. Adding lay­ers of mate­ri­als to increase ener­gy effi­cien­cy results in chal­leng­ing many con­trac­tors’ bud­gets and sched­ules.

The hier­ar­chy of needs has focused the atten­tion of design and con­struc­tion pro­fes­sion­als on meet­ing chang­ing build­ing codes first. Wall com­po­nent man­u­fac­tur­ers have respond­ed by pro­vid­ing code-com­pli­ant acces­so­ry mate­ri­als that can be added to mason­ry and steel frame wall con­struc­tion. How­ev­er, many of the options stop at min­i­mum code com­pli­ance with respect to ener­gy effi­cien­cy and air tight­ness, and do not sig­nif­i­cant­ly improve the per­for­mance of the build­ing from the per­spec­tive of fire safe­ty, storm safe­ty and long-term sus­tain­abil­i­ty.

Archi­tects, engi­neers and con­struc­tion com­pa­nies need to con­sid­er the fol­low­ing when eval­u­at­ing mod­i­fi­ca­tions to exist­ing wall sys­tems like con­crete mason­ry and steel con­struc­tion for school build­ing projects.

First Costs

Both con­crete mason­ry and struc­tur­al steel with light-gauge fram­ing require addi­tion­al insu­la­tion and air bar­ri­er lay­ers, and in some cas­es, mul­ti­ple insu­lat­ing mate­ri­als in an assem­bly. While these tra­di­tion­al sys­tems have been rel­a­tive­ly cost effec­tive to date, the increased num­ber of mate­ri­als and trades involved in pro­vid­ing a com­plete wall sys­tem today has made con­struc­tion slow­er, more com­plex and more cost­ly. Speed of con­struc­tion and increased labor costs are sig­nif­i­cant chal­lenges for these wall sys­tems.

Operating Costs

Both sys­tems can be designed to meet the cur­rent ener­gy codes, but are expen­sive in regard to achiev­ing high­er per­for­mance than code requires. Cost of main­te­nance and repair for con­crete mason­ry is good, how­ev­er light­weight steel fram­ing and cav­i­ty wall designs are still chal­lenged in the long term with mold, rot and over­all dura­bil­i­ty issues.

Health and Safety

Again, with prop­er air bar­ri­er and sealant design and con­struc­tion, either sys­tem can pro­vide a rea­son­able lev­el of air tight­ness to reduce the infil­tra­tion of aller­gens and pol­lu­tants into class­rooms. How­ev­er, cav­i­ty wall con­struc­tion is much more sus­cep­ti­ble to mold and rot which can be com­pound­ed by more air­tight build­ings. For both sys­tems, fire igni­tion bar­ri­ers must be installed over the insu­la­tion if it’s com­bustible. Con­crete mason­ry can only pro­vide major storm pro­tec­tion when ful­ly grout­ed. Steel con­struc­tion is not nor­mal­ly rat­ed for wind­storm pro­tec­tion.

Sustainability

For both sys­tems, it can be cost­ly to achieve more than code-com­pli­ant lev­els of ener­gy effi­cien­cy, but sig­nif­i­cant­ly hard­er for steel con­struc­tion than mason­ry. Mason­ry walls also con­tribute sig­nif­i­cant weight of mate­r­i­al to a project, while steel con­struc­tion requires many dif­fer­ent mate­ri­als to com­plete an assem­bly. Nei­ther sys­tem pro­vides any sig­nif­i­cant amount of recy­cled mate­ri­als. Build­ing life­cy­cles are usu­al­ly good with mason­ry con­struc­tion, yet only mod­est with struc­tur­al steel.

Improved Learning Environment

With prop­er insu­la­tion and air bar­ri­er design, both sys­tems can pro­vide a rea­son­able lev­el of air tight­ness and ener­gy effi­cien­cy. How­ev­er, it may be more dif­fi­cult to achieve opti­mal per­for­mance from the steel cav­i­ty wall con­struc­tion. Con­crete mason­ry can pro­vide bet­ter poten­tial ther­mal com­fort and noise reduc­tion than steel con­struc­tion, thanks to the insu­la­tion and ther­mal mass of the wall.

Con­tin­ue read­ing in our white paper, Lead­er­ship in School Con­struc­tion.

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