Applications of Different Insulation Materials

Insulation types and their applications vary depending where or what part of the house you need to install:

Bulk insulation materials

Mainly resists the transfer of conducted and convected heat, relying on pockets of trapped air within its structure. Its thermal resistance is essentially the same regardless of the direction of heat flow through it. Bulk insulation includes materials such as glass wool, wool, cellulose fibre, polyester and polystyrene. All bulk insulation products come with one material R-value for a given thickness. Bulk insulation traps air in still layers.

Reflective insulation materials

Mainly resists radiant heat flow due to its high reflectivity and low emissivity. It relies on the presence of an air layer of at least 25mm next to the shiny surface. The thermal resistance of reflective insulation varies with the direction of heat flow through it. Reflective insulation is usually shiny aluminum foil laminated onto paper or plastic and is available as sheets (sarking), concertina-type batts and multi-cell batts. Together these products are known as reflective foil laminates, or (RFL). Dust settling on the reflective surface greatly reduces performance. Face reflective surfaces downwards or keep them vertical. The anti-glare surface of single sided foil sarking should always face upwards or outwards. The total R-values for reflective insulation are supplied as ‘up’ and ‘down’ values. Total values depend on where and how the reflective insulation is installed. Make sure that system values provided by the manufacturer relate to your particular installation situation. Composite bulk and reflective materials are available that combine some features of both types. Examples include reflective foil faced blankets, foil backed batts and foil faced boards.

The building code sets out minimum requirements for the R-values of materials used in the construction of buildings. It is generally advisable to exceed these for greater comfort and energy savings. The higher the R-value, the better the thermal performance. Material R-values are supplied with bulk insulation materials and refer to the insulating value of the product alone. The higher the R-value the better the thermal performance. Total R-values are supplied with reflective insulation and depend on the product being installed as specified. R-values can differ depending on the direction of heat flow through the product. The difference is generally marginal for bulk insulation but can be pronounced for reflective insulation.

• ‘Up’ R-values describe resistance to heat flow upwards (winter R-values).
• ‘Down’ R-values describe resistance to heat flow downwards (summer R-values).

Up and down R-values should be quoted when installing reflective insulation in roofs, ceilings and floors. It is extremely important to ensure that your insulation is installed by competent, experienced professionals. Badly-installed insulation which is crammed in too tight, has gaps or gets wet will do little to protect your home, even if it's material with very high R-values. Also for using insulation materials, the walls and roof spaces also need to be constructed properly, using appropriate framing techniques, radiant barriers and other approaches to reducing heat transfer. And most importantly, insulate the foundations, basement walls and slabs, especially in colder climates.

Underfloor Insulation

If you live in a home with timber floors, underfloor insulation is a particularly effective way to get on top of winter chills. High quality underfloor insulation not only stops cold draughts from whistling up between floorboards, it also creates a barrier against moisture that will ensure mould can’t take hold beneath carpets during the wet months. Slabs on grade can be insulated by digging around the perimeter and installing foam board. When the building is new construction, then it might be easier to only install the foam board against the exterior of the slab and footing, or under the slab. Slab foundations with interior insulation provide more termite resistance, but some builders in the southeastern United States have even reported termite infestations through foam insulation on contained slabs.

Underfloor insulation is required for in cool climates and often in other climates. Insulate the underside of suspended floors:

• in cool temperate and alpine climates
• in temperate climates in some cases
• in high humid and hot dry climates where air conditioning is used.

Insulate the edge of slabs-on-ground:

• in cool temperate and alpine climates
• in temperate climates where slab heating is used.

Insulate the underside of slabs-on-ground:

• in alpine climates
• where groundwater is present.

Enclosing subfloor spaces in mixed climates may be sufficient to reduce heat transfer.

Having a timber floor insulated professionally, including filling the gaps between the floorboards and around the skirting, depends on the size and shape of the room and the insulation material used, but typically costs around £800. The insulation will make the room feel warmer in the winter and reduce heating bills by as much as £90 per year.

Underfloor insulation is a simple and effective way to keep your home warm and reduce your energy bills. Regardless of whether you have a suspended wooden floor or a concrete floor, improving your undefloor insulation could save you money. You may also be able to get financial help and other support to help you pay to have the insulation installed by a professional. Solid insulation boards, or rolls of mineral fiber similar to those used to insulate lofts can be fitted between the flooring joists. If your floor is above an unheated cellar or basement you will need to fit the insulation tightly between the joists and secure in place with netting if needed. Plasterboard should then be fixed to the ceiling of the basement to provide fire resistance. If a floor is being replaced, this is a perfect opportunity to improve the standard of insulation. In fact, where this is the case, upgrading your floor insulation is required in order to comply with building regulations. Insulation can be added over the existing concrete slab or underneath a new one. Where insulation is placed above the slab, the rooms will warm up more quickly when the heating is switched on. High performance rigid insulation boards are often the best materials to insulate an existing concrete slab floor, as they provide the best thermal performance at any given thickness. Keeping the thickness of your insulation to a minimum will reduce the likelihood of having to make costly alterations to door openings, stairs and other fixtures as a result of the increase in floor heights.

A Well Insulated House

Having a good house insulation is not only a great way to live toward a greener ideal, but to also save yourself some money on heating and cooling bills. Increasing the thermal insulation in an existing home doesn’t have to be difficult, and the financial payoff can be substantial in the long run. It is more cost-effective to add house insulation during construction than to retrofit it after the house is finished. To properly insulate a new home, you’ll need to know where to insulate and the recommended R-values for each of those areas. Use a tool to determine where you need to insulate and the recommended R-values based on your climate, type of heating and cooling system, etc. Once you know where you need to insulate and the recommended R-values, review our information on the types of insulation to help you decide what type to use and where. Before you insulate a new home, you also need to properly air seal it and consider moisture control. When remodeling, one of the best and fastest ways to insulate is using blown-in insulation. Blown-in insulation, when installed with the dense pack technique, will offer superior air sealing. It can be installed easily, reducing the amount of preparation needed. If you’re remodeling and your wall cavities will be open, look into two-part spray foam or wet spray cellulose insulation. If you are building a new home, then there are many alternatives to choose from, including structural insulated panels, insulating concrete forms, and insulated concrete blocks. All of these materials are considered insulating materials as they are manufactured with the purpose of increasing R values on a building. If you’re building a traditional framed house, consider using advanced wall framing techniques. These techniques improve the whole-wall R-value by reducing thermal bridging and maximizing the insulated wall area.

In most climates, you will save money and energy when you build a new home or addition if you install a combination of cavity insulation and insulated sheathing. Reduce exterior wall leaks by taping the joints of exterior sheathing and caulking and sealing exterior walls. Cavity fibrous or cellulose insulation can be installed at levels up to R-15 in a 2 inch x 4 inch wall and up to R-21 in a 2 inch x 6 inch wall. R-values can be higher for foam insulation and other advanced insulation systems.

Three critical elements of house insulation strategy are:

1.    The type of insulation material to be use

2.    Where it is installed to be installed

3.    And how much is needed

If there is no upcoming work being done on the home, you will want to consider which season is best for installation. Although, if you are in a cold climate some people wait until winter, hoping that prices will become lower, the cost of insulation actually remains fairly constant throughout the year. The best option is to choose an installation time that will increase energy cost savings. If you're having a new home built, be sure to talk to your builder about these elements so that you can be assured the house insulation strategy will contribute to a comfortable, efficient home.