A large majority of older homes do not have cavity wall insulation, however as energy costs rise and concern for the environment increases, many are opting to install insulation in their already existing homes.

There are two primary techniques that can be employed when installing cavity wall insulation in older homes. The first involves drilling holes into either the interior or exterior section of the walls and injecting insulation into them.

Before installing the cavity wall insulation, it is important to look out for planks of wood, usually four by two inches in size, placed horizontally midway up the wall cavities.

If these are identified, home owners will need to drill holes above and below each plank of wood to ensure each cavity is evenly filled.

Similarly, check for knob-and-tube wiring in the walls, as insulation cannot be placed over this type of wiring because the wires depend on air circulation to keep cool.

In terms of insulation materials to inject, Dwight Barnett recommends closed-cell expanding foams “as they would both insulate the wall cavities and also serve as an air barrier and vapour retardant, making the project more energy-efficient,” however cellulose can also be used.

Barnett advises that you “drill holes on the interior side of the wall to inject insulation into the wall cavities.” Once insulation is installed the holes can be patched up and the walls repainted to cover any markings.

Cavity wall insulation can also be installed into older homes by pulling exterior walls apart entirely and placing it inside the wall cavities by hand, rather than injection.

For home-owners already renovating their older home, this method is ideal as it is cost-effective and simplifies the process.

Bill Kibbel supports this method, as he believes it ensures the insulation is “installed properly …[which] prevent[s] issues with uneven distribution and moisture condensing.”

Kibbel argues that injecting insulation into wall cavities of older homes can cause some areas to receive too much insulation material while other areas receive little or none.

It is recommended that home-owners who are not planning on renovating but wish to enhance the warmth and energy-efficiency of their home first focus on reducing drafts.

These areas can either be identified by the home-owner, or they can seek out the assistance of contractors who can identify points of air infiltration in the home.

Kibbel explains that contractors have devices on hand that operate in a manner that creates a negative pressure, which causes air to come in at all the leaky points. The leaks can then be identified and sealed using a smoke puffer.

To read more from Dwight Barnett, click here, meanwhile if you were interested in the opinions of Bill Kibbel, click here

Photo: a Creative Commons Attribution 2.0 from Better Business Listing’s Flickr
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