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Homeowners insulate their new or existing home to increase comfort or improve energy performance. Indeed, correctly installing insulation will make significant changes in your property.  

There are vital factors that you need to consider when carrying out this project. For instance, the Building Code of Australia (BCA) has provided total R-value for each climate zone. Therefore, it’s crucial to comply with these requirements when selecting insulating the roof and ceiling of your home.

Insulation work completed in Bendigo

Issues to Consider when Insulating your Roof 

There are different issues that you need to address when insulating your home to avoid compromising the effectiveness of the insulation. The following are the concerns. 

1. Vapour Barriers

Vapour barriers are practical in cold climates with a significant difference between the indoor and outdoor temperatures. 

It is recommended in high humid or tropical climates, in raked or cathedral ceilings due to their low ventilation. More so, you can use it on the exterior of the metal roofing to minimize the chance of corrosion and condensation.  

It requires you use adhesive or tape on all joints to make the vapour barriers to moisture-resistant. 

Some of the common vapour barriers are reflective foil, polythene sheeting, painted surfaces that are water-resistant and well maintained as well as foil-backed plasterboard. Additionally, polystyrene, which is a water-resistant insulator, can act as a vapour barrier. 

Install Vapour barriers in the following ways. 

  • On the exterior of the insulation if you are living in warm climates.  
  • Install it on the interior of the insulation in cold climates. That is next to the internal lining of the wall or above the lining of the ceiling.  

2. Thermal Bridging  

The frame of your building can serve as a thermal bridge, particularly in cold weathers. For instance, metal framing is a considerable challenge due to its high conductivity. Thus, the presence of this material on your property lowers the overall insulation value. Because these frames are found in walls, floor or selling surface hence making 15% of the entire building.  

However, you can overcome this challenge by incorporating the following practices.  

  • Fix polystyrene isolating strips of at least 12mm between the cladding and the metal frame. The R-value of this material should be 0.2. 
  • Install bulk insulation over the internal and external surface of the metal frame. You can use polystyrene boards for bulk installation.   

3. Gaps 

You should evaluate the condition of the roof before installing the insulation and always ensure that there are no small gaps throughout the life of the ceiling. Gaps, no matter how tinny they are, can reduce the value of the insulation significantly. Therefore, make sure that there are no gaps left around the pipes and ducts installing batts. Ensure that joints and holes are taped up in reflective insulation while the concertina foils and multi-cell are sealed. 

Additionally, areas, where heat leaks the most, should be well insulated. These are areas such as ceilings, wall corners and floors. You should also have minimum clearances around recessed downlights, fire flues, as well as transformers. 

4. Roof Ventilation 

It’s essential to have your roof space well ventilated for it minimizes the build of the heat. This is done even in colder climates for this will allow moisture to escape. You can achieve minimal ventilation by creating air gaps between tiles or along the ridgeline. You can also use eves or gable vents to create ventilation on the roof.  

Tropical or high humid climates also need ventilation. However, having a ventilated roof spaces under the metal roofing will cause condensation at night. The condensation will begin dripping on the underneath of the metal roofing and the ceiling. 

You can prevent this installing anti-condensation blanket under the metal roof or reflective foil sarking. Further, you can close the openings at night to prevent air from flowing into the roof space.  

Homeowners living in areas prone to bushfire should cover the vents using a mesh of fine stainless steel to keep cinders off. Further, you should keep it vermin proof and weather tight.  

Roof and Ceiling Insulation  

Insulating the roof and the ceiling can save your energy bill significantly. It’s said that you can save up to 45% of the energy needed to both heat and cool the house. The following are different type of roofs and ceiling found in most homes in Australia. 

Wall and ceiling insulation done in Bendigo

Slanting Roofs and Flat Ceilings 

The BCA provides different requirements for roofs and ceiling insulation based on climate zones. 


You can place the second layer of foil batts or sarking below the roof to improve radiant heat resistance. Leave a 25 mm gap between the materials while the sarking is installed beneath the roofing materials or between the rafters and the battens. Always ensure that the reflecting side is facing down. 


Use batts and polystyrene boards for the bulk insulation and ensure that the insulation is placed between the joists. Homeowners residing in the alpine climates can install an additional layer on the bulk insulation to enhance thermal performance.  

Covering ceiling joists with insulation is not recommended because you have to remove the insulation whenever you are inspecting the roof space. You need to note that every insulation has to comply with the Australian Standard, and this includes the one you do when examining the roof.  

Ceilings Following the Roof Line

These are ceilings without accessible roof space for ample insulation. They include cathedral ceilings, sloping ceilings, skillion roofs or vaulted ceilings.  Although you can choose such a ceiling for your property, it’s essential to leave enough space that will allow adequate insulation and air gaps. 

Health and Safety Measures during Insulation 

Installing ceiling insulation can be dangerous, especially when you do it yourself without the assistance of insulation experts like Bendigo Insulation services.  

The following are the preparation and safety tips that should be adhered to during the process.  

  • Invite an expert to inspect the wiring in the ceiling before covering it with an insulator. It’s worth noting that some old wiring can begin overheating and cause fire due to the insulation material. 
  • It’s vital to invite insulation installation experts with adequate skills and knowledge to carry out the project. 
  • Switch off electricity at the switch box when inspecting and installing insulation.  
  • Wear protective clothing like gloves, and face mask when working in dusty areas, installing mineral wool, glass wool and cellulose fibre. These insulation materials irritate the eyes, skin and respiratory tract.   

Additionally, any person installing reflective insulation should wear adequate eye protection because this insulation material can cause dangerous glare.  

Installation of material

Further, installing the insulation material on the roof exposes you to the risk of sunburn.   

  • It’s not recommended to work alone for this exposes you to several dangers. Therefore, ensure that there is someone available to keep an eye on you while working or to hold your ladder as you enter or climb down from the ceiling.  
  • The increased use of downlights penetrating the ceiling has led to cases of ceiling fires. For that reason, ensure that there is no transformer beneath the insulation and a minimum clearance is maintained around the downlights, hot flues, appliances and fittings as well and exhaust fans. Further, you should have a minimum clearance of approximately 50mm around the incandescent lights and halogen lights. Always refer to the Australian Wiring Rules.  
  • Metal materials should be kept off, and avoid reflective foil near electrical wiring and fittings. Further, don’t secure these insulation materials with metal staples. 

Contact Bendigo Insulation services for more information and quotes.  

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