Wall Insulation For Existing Homes

Wall Insulation For Existing Homes

Many older Australian homes are missing wall insulation. If you experience costly power bills, a cold home in winter and hot conditions in summer you may need to turn your attention your walls. Without wall insulation you may be losing as much as 25% of your homes heating in winter and cooling in summer. Installing wall insulation will reduce your reliance on heating and cooling appliances and save you money on your next energy bill.

Should I Replace My Wall Insulation?

Wall Insulation is built to last for years however insulation that is 10 years or older may need to be checked for damage, mould or rodents. Over time, insulation may lose its effectiveness and the R-value reduced due to compression, moisture or movement creating gaps in the insulation.  Rotting or damaged insulation may require replacement and installing new insulation into the area required. There are a number of retrofit options for an existing home, including a variety of insulating materials such as; fiberglass, blow in cellulose and spray foam.

Fiberglass vs Cellulose vs Spray Foam For Wall Insulation

The application of retrofitting wall insulation using spray foam, fiberglass and cellulose is the same, however the material used differs between these applications.

Fiberglass insulation the most common insulating material and is available in batts, rolls or loose fill which can be easily sprayed into place. This insulation type in inexpensive, effective and has a high fire rating.

Blow in cellulose insulation in an inexpensive product however it requires more effort than fiberglass installation as training is required before using the blow machine. As cellulose insulation is manufactured from ground up paper it has a lower fire rating. Overall, this product is quite effective however but has a short lifespan and can get blown around leaving gaps between the insulation material.

Spray foams are more expensive compared to the other options, and as it must be installed by a professional, this increases the overall cost of the product. In general, spray foams have a longer lifespan, are permanent and will not sag or loose its R-value over time.

Spray foams comes in two forms; open and closed cell structure. Open cell foam has air gaps inside the material and occupies more space per weight, it can be easily installed and has a lower cost than closed cell foam. As the foam expands it is effective at filling air spaces and preventing air draughts. Closed-cell foam is more common and denser giving it a higher R-value rating.

Wall insulation Batts Vs Blown-In

A major renovation project or extension with brick-veneer or weatherboard walls, provides the perfect opportunity for wall insulation batts to be easily installed. However, when the wall lining is not being removed it becomes more complicated to install insulation. In this case, pump-in cavity wall insulation can be used as it is made of small insulation particles which easily conforms to any space. The R-value achieved by blown-in insulation, depends on the material used and the thickness of the wall cavity. During installation of blown-in, it is important to ensure that the insulation material does not collect any moisture as it passes into the wall cavity as this can compromise its performance.

How to retrofit Wall Insulation?

Installing blown-in wall insulation into existing walls, can be done with brick veneer, cavity brick or weatherboard walls. A blowing machine is used to insulate the walls and access to the cavity space is achieved by lifting tiles above the cavity. A special hose is then dropped into it, and gradually lifted as the cavity fills. If the cavity is not accessible in this way, then a small hole is made in each cavity (from the outside) and material is pumped through to fill each wall space. Installing insulation into existing walls can be a tricky and complex process, therefore we recommend you seek professional support and advice before commencing. Visit our “How to install insulation” page for more information and videos.

Wall Insulation Batts – Brand Comparison

Insert Video – Pink Batts vs Earthwool vs Bradford Insulation

Pink Batts made by Fletcher insulation is a glasswool insulation batt, made from up to 80% recycled glass material. Its new soft touch technology gives the insulation a low-itch feel making it easy to install. It is a lightweight and firm batt which keeps its shape once installed and has a life span of up to 50 years.

Knauf Earthwool is a glasswool insulation product and is the least itchy of the three brands. It is made of 80% recycled glass and has no added formaldehyde. It is odourless, rot proof and does not sustain vermin, thus being an attractive product for older houses.

CSR Bradford has been manufacturing insulation in Australian for over 80 years and has a large variety of insulation products on offer. When properly installed Bradford insulation can be expected to last as long as your home!

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2 thoughts on “Wall Insulation For Existing Homes

    • Pricewise Insulation says:

      Hi Sally, insulating existing walls with blow-in insulation is difficult because of all the timber joists that are in the way. There are companies that do this (such as Enviroflex in Melbourne), however it is quite expensive. If you are renovating then one option is to remove the plasterboard or weatherboards, install R2.5HD Knauf Earthwool Insulation Sound Shield Batts and then install new plaster and weatherboards. We understand that this is not an easy or cheap solution, however once it’s complete the insulation is designed to work effectively for decades. Feel free to give our team a call on 1300 729 639 if you have any questions.

      Pricewise Insulation

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