When architects, builders, and contractors design or construct buildings, they must follow a set of standards known as building codes. These guidelines ensure that structures are safe and conserve energy.
More stringent code requirements for insulation have become a pressing issue for many builders and remodelers. Choosing efficient, economical insulation is essential to meeting these new regulatory requirements.
What is a Building Code?
Building codes are rules that govern the construction of commercial buildings, homes and other structures in a given area. Local governments typically set these regulations with the help of architects, engineers, builders and construction professionals to ensure the safety and strength of structures in their jurisdictions. The rules, which are enforceable by law, usually include specifications for structural integrity, fire safety and energy conservation.
The process of developing, approving and enforcing building codes varies by country. In the United States, state and city officials often reference model building codes—such as the International Building Code (IBC)—as a guide for their own local rules. Model codes are developed and updated by a group of industry experts—such as ICC-appointed technical committees and working groups—who utilize research findings from the National Institute of Standards and Technology (NIST) and other organizations to update the rules as needed.
As with any set of regulations, it is possible for disagreements to arise between inspectors and builders over how a specific rule should be interpreted. To avoid misunderstandings, keep lines of communication open and provide inspectors with research reports that support your construction practices. This helps build trust and ensures that your structure is built to the best standard.
What is Insulation?
Insulation is a non-conducting material used to stop the flow of heat, electricity or sound between two conducting materials such as walls or wires. It also stops the spread of fire in a home or building. Insulation is a key component of good passive design and can be found in floors, lofts, ceilings, wall cavities, pipes and other spaces that allow hot air to escape or cold air to invade. Insulation can also reduce noise and improve energy efficiency in the home or office.
Most insulation is rated by the amount of heat it resists, which is known as its R value. The higher the R-value, the more effective the insulation. The NCC specifies minimum R-value requirements for different climate zones.
Good insulators have a structure that traps pockets of air, which helps to keep the warm air inside in winter and cool air out in summer. This makes them a natural choice for roof insulation, and there are a variety of products available to meet different needs and budgets.
Cellulose, fiberglass, mineral wool and spray foam are all popular forms of insulation in Australia. Each has its own strengths and weaknesses, but all provide good R-values for relatively low cost. Spray foam is particularly suitable for gaps and crevices, but is not ideal for use in exposed areas of the ceiling where it could absorb moisture or mould.
What is Continuous Insulation?
Using continuous insulation (ci) in the wall assembly dramatically reduces energy losses and increases building performance. This approach also helps eliminate moisture problems, a common source of mold and other damage.
In addition, ci makes code compliance easier for builders, and it provides better building comfort, reduces construction defects and results in stronger, more resilient buildings that last longer. And because it helps reduce the consumption of non-renewable fossil fuels, lowers dependence on foreign sources for that energy and limits greenhouse gas emissions, CI is also good for the environment.
To meet current IECC and ASHRAE energy codes, the insulated sheathing must be R-38 or higher. Unlike cavity insulation materials, which must be bridged by wood or steel framing members, sheathing is a continuous barrier to thermal transfer and must meet the same R-value requirements as the rest of the wall.
Atlas Molded Products offers a wide variety of building materials that help builders comply with a number of prescriptive and performance-based insulating R-value requirements for commercial wall assemblies in all climate zones. These include a combination of rigid foam insulation and a reflective foil facer, which is ideal for the sheathing of most wall systems including stucco, brick or fiber cement. These insulation products are also available in sheets or fanfold, making it easy for builders to choose the right thickness for their projects.
What is Slab-on-Grade Insulation?
If your home is built on a slab-on-grade foundation, a layer of insulation under the concrete is a must. It reduces heat loss in winter and condensation of humidity on the floor in summer. It also saves energy on air conditioning by keeping the indoor air temperature lower.
Most Building Codes require slab-on-grade floors to be insulated to a minimum of R-5. However, the insulation must not be placed more than 24 inches below grade (or to the edge of a framed wall). In climate zones 4 and higher, builders may use continuous horizontal R-10 or more under the slab, which will greatly increase the comfort in the home.
In the ENERGY STAR Single-Family New Homes National Rater Field Checklist and the ENERGY STAR Multifamily New Construction National Rater Field Checklist, Item 3.2 and Item 3.4 require that slab-on-grade foundations have insulation at the perimeter of the monolithic slab and footing in alignment with the perimeter of the walls. This is typically accomplished with rigid insulation such as XPS or rigid fiberglass.
Insulating the edges of a slab-on-grade foundation prevents thermal bridges through the highly-conductive concrete and allows for easier heating and cooling in the home. This is especially important in colder climates where a poorly-insulated slab can lose substantial amounts of energy due to conduction. Also, a slab that is not properly insulated can draw moisture from the soil through the slab perimeter and into the basement, which can promote mold growth and compromise indoor air quality.