subject: House Insulation [print this page] House Insulation House Insulation
If you are one of those paying more than necessary to heat or cool your house you may consider insulation for your house. A well-insulated house is like dressing appropriately for the weather. A wool sweater will keep you warm if the wind is not blowing and it is not raining. On a windy, rainy day, wearing a rain-coat would keep you both dry and warm. A house is not different in fact. On the outside surface of your house under the brick or siding, there is an air barrier that does the same thing as the nylonit keeps the wind from blowing through. Then there is the insulation (like your sweater) and a vapour barrier, which helps keep moisture away from the house structure where it can damage.
The following signs may be helpful to see if you have home insulation problems or not:
In the winter
walls cold to touch
cold floors
high heating costs
uneven heating levels within building
mold growing on walls
In the summer
uncomfortably hot inside air
high cooling costs
ineffectiveness of air conditioning system
mold growing in basement
What shows the effectiveness of an insulation material is its R value. The higher R values mean higher resistance to heat exchange through it.
In the following table you can find common insulation materials and their properties:
Insulation Material
(R/m)
Appearance
Advantages / Disadvantages
Fibreglass
3.03.7 (2126)
All batts come in plastic-wrapped bales. The products are like fibrous blankets, about 1.2 m (48 in.) long and wide enough to fit snugly between walls studs.
Readily available.
Mineral wool
2.83.7 (1926)
Same as fibreglass.
Somewhat better fire resistance and soundproofing qualities than fibreglass.
Cotton
3.03.7 (2126)
Not readily available.
Loose-Fill All loose-fill insulations typically require a professional installer.
Fibreglass
3.03.7 (2126)
A very light fibrous fill, usually pink or yellow.
Can be affected by air movement in attics.
Mineral fibre
2.83.7 (1926)
A very light fibrous fill, usually brown.
Cellulose fibre
3.03.7 (2126)
Fine particles usually grey in colour, denser than glass or mineral fibre.
Provides more resistance to air movement than other loose fill insulations. Can have settlement problems if not installed properly.
Board-Stock
Type I and II (expanded) polystyrene or EPS
3.64.4 (2531)
White board of small about 8 mm (0.3 in.) in diameter foam beads pressed together.
Typically HCs used in production. Must be covered.
Type III and IV (extruded) polystyrene or XPS
4.5 5.0 (31 35)
Commonly blue or pink foam board.
Works well in wet conditions, can act as a vapour retarder. HFC usually used in production. Must be covered.
Rigid fibreglass
4.24.5 (2931)
A dense mat of fibres, typically less rigid than polystyrene.
Drains water away. Sometimes hard to find.
Rigid mineral fibre
4.24.5 (2931)
See Rigid fibreglass above.
Drains water away.
Polyisocyanurate
5.66.7 (3946)
Foil-faced rigid foam.
HFC usually used in production.
Spray-Applied All spray-applied insulations fill cavities very well. They must be applied by a specialized contractor.
Wet-spray cellulose
3.03.7 (2126)
Fine particles held in place by a binder.
Open-cell light density polyurethane
3.6 (25)
Soft, compressible spray foam that expands into the cavity.
Can act as the air barrier if combined with another material. Must be covered with a vapour barrier.
Closed cell medium density polyurethane
5.5 6.0 (38 42)
Rigid spray foam that expands into the cavity and sets up fairly rigid.
Can act as the air barrier and vapour retarder. HFC used in production. Must be covered.
Effective insulation systems block the heat transfer and also they act as moisture barriers. For this purpose they have the following features:
• An air barrier, which prevents the movement of interior or exterior air through the system.
Carefully filled cavities, which leave no gaps in or around the insulation and which do not compress the insulation.
A minimum of thermal bridges. These are parts of the wall that, with a lower R value, extend from the warm side to the cold side of the insulation, giving heat an easy escape. The structural members in the wall will often be thermal bridges.
A vapour retarder, such as polyethylene sheeting, which prevents moisture from moving from warm interior spaces into a colder building envelope where it could condense.
Drying potential, which is the ability of the insulated assembly to release any moisture that gets into the system.
As can be understood from all the above explanations home insulation is unfortunately not a DIY job. It requires experience, technical knowledge and expertise.
