How to Replace Old Home Insulation

The insulation in the home is often the most overlooked home maintenance issue that homeowners face. However, replacing insulation can have a hugely positive effect on your home’s energy efficiency and air quality.

Not all old homes are insulated properly and the quality of houses insulated decades ago can vary. The state of the insulation will depend on the type and quality of the insulation that was initially installed, and how much the insulation has degraded over time.

In this blog, we will discuss why insulation needs to be replaced, how to recognise the signs that it’s time to do so, and provide a step-by-step guide for installing new insulation.

Signs That Your Insulation Needs Replacing

Recognising old or damaged insulation:

The signs of ineffective insulation are relatively easy to spot if you know what to look for.

The first signs don’t even require looking at the insulation itself. However, if you notice draughts, uneven indoor temperatures, or high energy bills, you should undergo an insulation inspection.

During your inspection, you can look for physical signs. These are things like sagging, dampness, gaps, or mould growth on the insulation itself. Small rodents are also a clear sign of damaged insulation.

Remember that old insulation standards are lower than today’s standards and higher R-values are now available for homes in Australia.

How age affects insulation performance:

Older homes built in the 1970s or earlier need to have their insulation replaced, especially if the insulation hasn’t been replaced since.

Common types of insulation in older homes include old fibreglass batts, cellulose, rockwool, foil, sawdust, wool, and polyester. You’ll find that many of these materials are dusty, may contain fire retardants or formaldehyde, and are infested by rodents. These types of insulation also degrade over time, eventually requiring home insulation replacement.

Depending on the material, insulation typically has a lifespan of 15-20 years. With advancements in technology, we now have brands like Earthwool that extend the lifespan of their insulation to 50 years and have a much higher R-value than older types of insulation. 

However, even these modern insulation products can lose their thermal effectiveness due to moisture, rodent infestations or large gaps between the batts. So even if your home was insulated 10 years ago, it might still be worth checking if it is working effectively.

Preparing for Insulation Replacement

Assessing the current state of your insulation:

Removing old insulation is recommended if it’s damaged, contaminated with mould, or infested with pests.  

In older homes, it is not uncommon to find rodents, droppings, nests, rubbish from trades and previous occupants, old tiles, water leaks, and several other issues that may be reducing the effectiveness of your insulation.

Start by inspecting the different areas of your home, including the ceiling and underfloor areas. Look for signs of deterioration like those mentioned earlier—sagging, dampness, and mould. 

If the insulation is in good shape and only needs to be added to, you can save money by adding a new layer of insulation on top. 

Consider consulting a professional if you’re unsure. They can inspect your home and recommend the best next steps after examining the state of your home’s insulation.

Choosing the right insulation material:

The most important part of your insulation replacement project will be choosing the right insulation material. Many options are available, each with its pros, cons, and costs.

Fibreglass, also known as glasswool, is a common material used in house insulation that’s made from recycled glass bottles, sand, and a handful of other ingredients. Some of the more reputable glasswool brands in Australia include Earthwool, Bradford, and Kingspan. 

Polyester is available in limited R-values compared to glasswool and is typically more expensive. It’s a high-quality insulation material that is great for underfloor spaces where moisture is an issue. However, polyester does not absorb moisture itself.

Spray foam has amazing insulating properties and can help seal air leaks. This type of insulation is not common in Australia and can be quite costly. Special care must be taken so that the spray foam does not cause structural damage to the building. 

Cellulose is made from recycled materials but isn’t as durable in damp conditions. It is also more expensive. 

Safety considerations:

Protective gear should be worn when removing insulation from your home. Always wear safety gloves, masks, and goggles to avoid irritation and contact with the eyes, skin, or mouth.

Older homes may also contain harmful asbestos. If you believe your home may have asbestos, do not attempt to remove the insulation yourself. Hire a professional to safely dispose of it.

Step-by-Step Guide to Removing Old Insulation

Gather necessary tools and materials:

Make sure you first have the right tools to remove old insulation. Depending on the type of insulation you are removing, utility knives, wooden sticks, plastic sheeting, and disposal bags will all be needed.

Hiring a construction vacuum cleaner or professional removal company may be the best option for larger homes or those with more complicated insulation issues. Companies like EcoHome in Victoria have industrial vacuums specifically for insulation removal.

If you still wish to take on the project yourself, you can remove batt insulation by hand. You can use a large dustpan and brush for gathering loose blow-in insulation and a vacuum cleaner can collect the rest of the smaller debris.

Isolating the work area:

Prepare the work area by sealing off doors and vents to prevent dust from spreading through the house. You can use drop cloths or plastic sheeting to protect your floors and furniture.

Removing the old insulation:

You’ll want to begin by carefully removing batts or blow-in insulation. Be careful not to damage the structure of your home, cause contamination, or create unnecessary dust. 

When removing batt insulation, gently lift and place it into disposal bags. Blown-in insulation can be swept up and vacuumed. 

Throughout the insulation removal process, follow safety protocols and beware of hazards like exposed electrical wiring.

Proper disposal of old insulation:

Bag and dispose of the old insulation materials and check with your local authority for the appropriate disposal method. This could involve taking your waste to a designated waste facility.

Installing New Roof Insulation

Preparing the space for new insulation:

Prepare the space by cleaning the area thoroughly and vacuuming smaller particles. 

You should also take this time to inspect the area for any leaks, cracks, or other issues that may need repairs first. It’s much easier to do these repairs before the new insulation is installed.

Installing the new insulation:

You should always follow the manufacturer’s instructions to place the insulation correctly. Make sure the insulation batts are fitted tightly between the joists, without compressing them. 

You’ll want to make sure the insulation achieves the recommended R-value for your region. An R-value is a number that tells you how good a material is at resisting the flow of heat. If it has a high R-value, that means it resists the flow of heat well.

We generally recommend installing a minimum of R4.0 ceiling insulation. However, if your budget allows then we would recommend upgrading to R5.0, R6.0, or higher in Melbourne, Sydney, and Adelaide. Knauf Insulation is now producing R7.0 and R8.0 Earthwool Ceiling Batts for high-performance homes.

Sealing gaps and air leaks:

In addition to installing new insulation in your roof space, you can also seal any gaps or cracks around windows, doors, and electrical outlets to reduce draughts. Use caulk or spray foam to seal smaller gaps and weatherstripping for doors and windows. This will help to improve both the comfort and energy efficiency of your home.

Post-Installation Tips and Maintenance

Inspecting the installation:

When finished, conduct a final inspection to look for gaps. Check around the edges and corners to confirm that the new insulation has been properly installed. 

This step is often overlooked so be sure to check your work upon completion to save time and money in the long run. 

Ongoing maintenance tips:

Maintaining your home’s insulation is an ongoing process that needs to be inspected periodically. If you have any work done in your attic or ceiling space by another trade, always check to make sure that insulation has not been displaced or damaged.

You can also add insulation to the walls and underfloor spaces of your home to improve your energy efficiency even more.

Learn More with Pricewise Insulation 

Pricewise Insulation is a 100% Australian, 100% family-owned business with over a decade’s worth of experience in the industry. 

Contact us today for more information on insulation for older homes and see how Pricewise Insulation can help transform your home!

Knauf Earthwool Ceiling Insulation Batts

From $ 8.68 p/m2 inc. GST

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This product has multiple variants. The options may be chosen on the product page

Bradford Polymax Ceiling Insulation Batts

From $ 17.86 p/m2 inc. GST

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This product has multiple variants. The options may be chosen on the product page

Bradford Hi-Performance Gold Ceiling Batts

From $ 15.63 p/m2 inc. GST

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This product has multiple variants. The options may be chosen on the product page

Pink Batts Glasswool Ceiling Insulation

From $ 6.83 p/m2 inc. GST

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This product has multiple variants. The options may be chosen on the product page

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