Building Science

Bautex Blocks Create Airtight, Moisture Resistant, Energy Efficient Walls

Ener­gy effi­cient walls are a key com­po­nent to the enve­lope of a high per­form­ing build­ing. Oth­er parts of the enve­lope include the roof, win­dows and doors, and foun­da­tion. An ener­gy effi­cient enve­lope is a ther­mal bar­ri­er that stops the flow of heat by air, vapor and radi­a­tion. The trans­fer of heat through a wall occurs by three pri­ma­ry mech­a­nisms: ther­mal con­duc­tion, ther­mal con­vec­tion, and ther­mal radi­a­tion. An ener­gy effi­cient wall should be con­struct­ed to pre­vent the flow of heat by all three of these mech­a­nisms.

Thermal Conduction - Transfer of Heat on the Molecular Level

Ther­mal con­duc­tion occurs when hot mol­e­cules spon­ta­neous­ly move towards and col­lide with cool­er mol­e­cules. The col­li­sion caus­es the ener­gy of the hot mol­e­cule to trans­fer to the cool­er mol­e­cule. Ther­mal con­duc­tion occurs in a wall when there is warm air on one side of a wall and cool­er air on the oth­er side of the wall. The warm air always moves towards the cool­er air. The more tight­ly packed (dense­ly) the mol­e­cules are in a sub­stance, the bet­ter the sub­stance con­ducts heat and the faster the hot air will move towards the cool­er air. The mol­e­cules in met­als are tight­ly packed. There­fore, met­al is a good con­duc­tor, and heat will quick­ly move through it. Wood is less dense than met­al, so it is a less effi­cient con­duc­tor of heat. So, wood build­ings lose less heat and stay warmer than met­al build­ings. Build­ings intend­ed for occu­pan­cy typ­i­cal­ly uti­lize low-den­si­ty insu­la­tion in their design, which slows con­duc­tion through the envelope.The effec­tive R-val­ue1 of a building’s wall assem­bly is its resis­tance to con­duc­tion. Prob­lems in a wall’s assem­bly, such as ther­mal bridg­ing, increase the wall’s con­duc­tiv­i­ty. An ener­gy effi­cient wall assem­bly should have low con­duc­tiv­i­ty and a high effec­tive R-val­ue.

Thermal Convection - Transfer of Heat by the Flow of Air

Ther­mal con­vec­tion occurs when heat moves from the warmer side to the cool­er side of a wall by the flow of liq­uid or air mol­e­cules. When occu­pants of a build­ing feel a draft, they are expe­ri­enc­ing ther­mal convection.Thermal con­vec­tion is often the biggest source of ener­gy loss in a build­ing. In wood-frame build­ings con­vec­tion occurs through the fram­ing con­nec­tions, wall, floor, roof, and fen­es­tra­tion inter­sec­tions. A tight­ly sealed build­ing enve­lope with ade­quate air and mois­ture bar­ri­ers can stop ther­mal con­vec­tion and cre­ate a com­fort­able envi­ron­ment for the occu­pants.

Thermal Radiation - Transfer of Heat by Solar Energy

Ther­mal radi­a­tion trans­fers heat from a warm area to a cool­er area by elec­tro­mag­net­ic waves, which for build­ings is main­ly the sun’s rays. Ther­mal radi­a­tion between two sur­faces does not require a medi­um, like air and water, to move through space. The two sur­faces need only be in view of each oth­er. All mate­ri­als absorb, reflect and emit radi­ant ener­gy. A material’s abil­i­ty to radi­ate absorbed ener­gy, or emit ener­gy as ther­mal radi­a­tion, is called emis­siv­i­ty. A high emis­siv­i­ty mate­r­i­al has low reflec­tiv­i­ty and will quick­ly absorb ener­gy that strikes it. The design of an ener­gy effi­cient wall should incor­po­rate mate­ri­als with high reflec­tiv­i­ty and low emis­siv­i­ty to lim­it the absorp­tion of radi­ant heat.

Bautex™ Walls Stop Thermal Conduction, Convection, and Radiation

The Bau­tex Wall Sys­tem deliv­ers a high-lev­el of con­tin­u­ous insu­la­tion and cre­ates a tight ener­gy effi­cient enve­lope. Con­tin­u­ous insulation2 in the con­struc­tion of a wall’s assem­bly stops the flow of heat by con­duc­tion, con­vec­tion, and radi­a­tion. Con­tin­u­ous insu­la­tion also pre­vents ther­mal bridg­ing, which is a com­mon issue with con­ven­tion­al con­struc­tion like wood and met­al fram­ing. Con­duc­tion tests were done on Bau­tex Blocks in accor­dance with ASTM C 518 – 10. The Blocks have an R-val­ue per inch: 1.84 and a whole wall R-val­ue (with con­crete) of R-14. Thus, Bau­tex Blocks stop ther­mal con­duc­tion. Also, The Bau­tex Air and Mois­ture Bar­ri­er reduces ther­mal con­vec­tion and ther­mal radi­a­tion by pre­vent­ing air, mois­ture, and ultra­vi­o­let waves from pass­ing through the wall. The Bau­tex Wall Assem­bly is ener­gy effi­cient and meets the ther­mal per­for­mance required of the IRC and IBC. Bau­tex Blocks are also easy to install, fire rat­ed, noise reduc­ing and storm-resis­tant. Bau­tex Blocks can be uti­lized in both com­mer­cial and res­i­den­tial build­ings and are the ide­al choice for ener­gy effi­cient wall con­struc­tion.

The build­ing and con­struc­tion indus­try use the R-val­ue as a mea­sure of ther­mal resis­tance or con­duc­tiv­i­ty. The effec­tive R-val­ue includes all the mate­ri­als used in its con­struc­tion: the dry­wall, studs, insu­la­tion, ply­wood, sid­ing, etc. The high­er the R-val­ue, the bet­ter the ther­mal per­for­mance the mate­r­i­al or sys­tem.

Con­tin­u­ous insu­la­tion cov­ers all parts of build­ing oth­er than the win­dows, sky­lights, doors, and build­ing ser­vice sys­tems. Con­tin­u­ous insu­la­tion helps cre­ate an insu­lat­ed, air­tight, and ener­gy effi­cient build­ing. The ASHRAE 90.1 and 2015 IECC require con­tin­u­ous insu­la­tion.