Featuring Plywood in Buildings - Engineered Wood Products ...

Thermal PerformanceThe real advantage of lightweight timberconstruction in a subtropical or tropical climateis the ability to provide very liveable buildingswith wall systems having low thermal mass.Thus in the cool of the evening following a hotday the wall will cool rapidly and not keepheating the interior. Walls with high thermalmass hold substantially more heat thuscontinue to radiate heat in the evening.In cooler climates, or if the building is to be airconditioned, the addition of insulation to thetimber structure can provide equivalentthermal insulation to solid construction. Forexample the addition of R1.5 batts into aplywood clad with reflective sisalation on90mm studs will result in a wall with anaverage R exceeding 2.2 (see table 2).Therefore, in winter a lightweight timber canbe a very effective insulator and keep thewarmth inside the building.Table 2 : Thermal resistance of timber framed plywood clad wallsR Value (m 2 o c/WattThroughInsulationZoneThroughStudOutdoor air film 0.04 0.0412mm Plywood Cladding 0.08 0.0820mm reflective air gap 0.58R1.5 Insulation 1.5090mm Stud 0.626mm Plywood Lining 0.04 0.04Indoor Air film 0.12 0.12TOTAL R VALUE 2.36 0.90Note:As a non-reflective 20mm air gap has an R value of 0.15, an insulation wall system withoutsisalation would reduce the total r value from 2.36 to 1.93 in the above table.8