By Candace Sofianos King
Timber iQ investigates the latest trends of using thermal insulation in timber construction.
Bulk insulation installed between rafters. Credit: TIPSASA
With the cost of heating and cooling in buildings escalating, timber structures are being increasingly favoured as the building method to keep these costs in check. Insulation in hollow structure walls regulate indoor temperatures, keeping homes warm in winter and cool in summer.
Apart from timber’s superior insulation properties, such buildings can be well insulated as ceilings and external walls can be filled with insulation. “The building envelope is the interface between the interior of the building and the outdoor environment, including the walls, roof and foundation,” says Des Schnetler, chairperson of Thermal Insulation Products and Systems Association SA (TIPSASA), a non-profit company that consists of manufacturers, suppliers, contractors and consultants in the South African thermal insulation industry.
“By acting as a thermal barrier, the building envelope plays an important role in regulating interior temperatures and helps determine the amount of energy required to maintain thermal comfort. Minimising heat transfer through the building envelope is crucial for reducing the need for space heating and cooling. In cold climates, the building envelope can reduce the amount of energy required for heating and in hot climates, the building envelope can reduce the amount of energy required for cooling,” says Schnetler.
Schnetler says it is advisable to install insulation in a suspended floor that is part of a building’s envelope with an R-value of at least 1m²K/W. Various types of products are available to suit the relevant application, Schnetler adds. The R-value is the measure of an insulation product’s ability to restrict heat transfer. It is therefore indicative of an insulation product’s thermal insulation performance.
“Apart from timber’s superior insulation properties, such buildings can be well insulated as ceilings and external walls can be filled with insulation.”
Addressing insulation challenges
“When insulating in timber frame construction, it is critical that the vertical insulation is of a rigid type to avoid sagging over time and therefore creating thermal bridging. The insulating material should also be a type that will not add additional fuel in the case of a fire,” says Trevor Henwick, regional sales manager: Eastern and Western Cape for Isover, a division of Saint-Gobain Construction Products South Africa.
Henwick continues, “The Knysna fires should be considered when specifying thermal insulation. The product used should also offer good acoustic insulation for better comfort. The correct thermal resistance as per the National Building Regulations needs to be complied with. Moisture barriers are critical for performance of thermal insulation and no shortcuts should be taken here.”
“Needless to say workmanship is one of the biggest challenges in the timber frame industry. Any potential homeowner should get references and follow up with the associations like the Institute for Timber Construction South Africa (ITC-SA). Clients should only deal with reputable companies that can back up claims of performance with tests done on their products. Well established manufacturers should be strongly considered first. Suppliers must be able to back up claims of sustainability with independent tests,” advises Henwick.
“Every year, millions of plastic PET bottles are thrown away into rubbish dumps and landfill sites. In addressing this major environmental problem, plastic bottles are converted into thermal insulation to be used to insulate buildings.”
Sustainability at the fore
In the midst of an energy crisis, South Africa’s buildings consume 40% of the country’s energy. An un-insulated building loses as much as 35% of its energy via its
Recycled plastic bottles have become a thermal insulation solution. Credit: Creative Commons
ceiling. Schnetler highlights that timber construction is heavily guided by Energy Efficiency Regulations. The current SANS 10400-XA: 2011 Edition 1 Energy Usage in Buildings provides clear performance requirements regarding the building envelope, notes Schnetler.
With sustainability at the top of the construction agenda, new innovative product developments have been made which are increasing the built environment’s green footprint. One sterling innovation is the use of recycled plastic bottles for insulation.
Every year, millions of plastic PET bottles are thrown away into rubbish dumps and landfill sites. In addressing this major environmental problem, plastic bottles are converted into thermal insulation to be used to insulate buildings. This type of material complements the architectural and construction practice of green building by increasing the energy efficiency of buildings and reducing the impact buildings have on human health and the environment.
According to ISOTHERM, thermal insulation manufacturer, such thermal insulation in ceilings, on geysers and water pipes can reduce energy consumption and cost, while regulating indoor temperatures. In accordance with the global trend to regulate the design and construction of buildings for maximum energy efficiency, South Africa has recently updated the National Building Regulation, namely SANS 10400. The new regulation stipulates that all new buildings or additions and alterations to existing buildings must comply with energy-efficient standards, including the insulation of floors, walls, windows, ceilings and roofs.
Deemed-to-satisfy thermal insulation requirements:
- Non-masonry walls shall achieve a minimum total R-value of 2.2m²K/W in climatic zones 1 and 6, and in climatic zones 2, 3, 4 and 5: 1.9m²K/W.
- Roof assemblies in climate zone 1 and 4 shall achieve a minimum total R-value of 3.7m²K/W; 3.5m²K/W in climatic zone 6; 3.2m²K/W in climatic zone 2 and 2.7m²K/W in climatic zones 3 and 5.
