A good house is well
insulated, well sealed, and has good ventilation. If you live
in a house which was built before modern insulation standards were
adopted it is very likely yhtat it was not insulated properly (if at
all) during construction.
Effects
Of Poor Insulation:
During Winter
Floors feel cold
Walls are cold to the touch
Different parts of the home are unevenly heated
Heating bills are high
Mold is seen on some walls
During Summer
House is too hot inside
Air conditioning system is ineffective
Air conditioning cost is high
Mold shows on some basement walls or floor
Measurement of
Insulation Quality
The R value or the metric
equivalent, RSI value, is a designation of the insulation
quality of insulating materials. The R value is a measure of resistance
the material posseses to heat passage. Local or other building codes
will usually specify minimum R value for new buildings.
How the insulation is installed largely determines its
effectiveness. Compressing the insulation or leaving spaces
around it will reduce the effectiveness of the insulation.
Characteristics
of common insulation materials
Fibreglass Batt
Insulation Material.
Is sold in plastic wrapped bales. The batts are about
1.2 m (48 in.) long and of the correct width to fit exactly
between wall studs.Readily available.
Mineral
wool
This is sold in batts and has better soundproofing and
insulation qualities than fiberglass. The main disadvantage is that it
costs more and is not commonly available.
Loose-Fill
Loose-fill insulations is done by professional
installers.
This is a very light fiber type fill, usually pink or
yellow in color.Air movement in attics may detract from its efficiency
by moving it around
Mineral
fibre A very light fibre type fill which is
usually
brown in color.
Cellulose
fibre Consisits of fine particles which are
usually grey in colour. It is denser than either glass or
mineral fibre.Due to its weight it provides more resistance to air
movement than other types of loose fill insulation.
Board-Stock
Expanded polystyrene or EPS
In form of white, blue or pink boards, of small foam
beads pressed together.
Good for use in in wet conditions, and can act as a
vapour retarder. Must be covered over.
Rigid
fibreglass
Consisits of a thick mat of fibres, normally less
rigid than polystyrene.
Will drain water away.
May be difficult to find.
Effective insulation systems slow the movement of heat
and of moisture . To accomplish this they must have the
following characterisitics:
Form an air barrier, which stops movement of air
through the system.
Well filled spaces with no gaps and with no
compression of the insulation.
Minimum of thermal bridges. These are structural parts
of the wall which go from the interior warm side to the exterior cold
side of the insulation, which heat can pass through.
A vapour retarder for example polyethylene sheeting,
which stops movement of moisture from warm interior spaces to colder
near exterior spaces where it condense to form water.
The ability to dry and to release moisture
which enters the system.
Wall Insulation for
Existing Construction
The two wall types commonly seen are
wood-frame or solid brick. To insulate a wood-frame wall, insulation in
the form of loose fill or foam is blown into the cavities through holes
that are drilled through the drywall on the inside or the siding on the
outside. In solid brick walls there is no cavity big enough for
insulation. A new wall is built inside and insulated during
construction, or board stock and new siding can applied to the exterior
although this is less effective. When planning a cavity wall retrofit,
remember the following:
The cost of building the new wall is high.
Air and vapour barriers are required. Interior drywall
is an air and vapour barrier. Insulation must be applied that will fill
the cavity without settling. Foam insulation, is an air barrier in
itself.
Attic Insulation
The attic is a cost-effective area to insulate. Most
commonly loose fill is blown between and over ceiling joists.
Alternastively batts laid on existing insulation may be used.
.
Basement Insulation
Basement walls must handle moisture from both inside
and outside the house. The most effective method, is to insulate walls
on the outside with rigid insulation materials which are suitable for
below ground use, for example extruded polystyrene or rigid fibreglass.
This has the following advantages:
Works well for damp-proofing and foundation drainage.
Rigid fibreglass or mineral wool will act as a drainage layer to keep
water away from the foundation.
The basement walls are maintained at room temperature,
which reduces the occurrence of interior condensation.
The disadvantages are high cost and the necessity of
covering the insulation above ground.
Interior insulation can be used. This can be done with
batt insulation between the studs, or with extruded polystyrene and
strapping on the face of walls. The advantages of interior
insulation are low cost and ease of application. The
disadvantages are as follows:
Any moist air moving through the wall from
the inside will condense on the wall on the outside.
Interior insulation should not be used in a basement
with moisture problems.
Is Insulating My
home Cost effective?
Good insulation systems will save money, cut
energy consumption and render the home more comfortable.