R4.0 Ceiling Insulation


Great value with R4.0 insulation

In terms of price versus performance R4.0 ceiling insulation is the best solution for your home, particularly if you live in climates like Melbourne and Sydney. However, insulation is a once off investment and many DIY builders are opting for higher ratings.


Save up to 40% on energy bills

According to the NSW government insulating your ceiling can reduce your heating and cooling costs by up to 40%. R4.0 ceiling insulation will help to reduce the heat-flow into the home, lessening the demands on heating and cooling systems.


Good for your health

According to ICANZ, a study in New Zealand showed that people living in insulated homes reported a significant improvement in health compared with those living in uninsulated homes. The adults living in insulated homes reported less sick days at work and children were less likely to take days off school.



R4.0 Insulation for Roofs and Ceilings

If you’re wondering whether your currently un-insulated home would benefit from thermal insulation batts, then the answer is in all likelihood ‘Yes’. R4.0 insulation is a fairly safe and economical recommendation for all but the most extreme climates in Australia.

How fat are the R4.0 Batts?

R4.0 insulation batts are typically around 20cm thick, though this does vary a little between brands. Earthwool R4.0 batts are the thinnest at 195mm, and GreenStuf R4.0 batts are the thickest, at 210m. Remember that it isn’t the thickness which determines the R-Value, thought these usually do correlate.

How do insulation batts work?

Insulation isn’t rocket science. One of the easiest ways to explain the way ceiling insulation works is to begin with let’s consider the effect of not insulating your ceiling. Anyone who has lived in a house without insulation will be familiar with the below scenario..

On a hot summers day:

The warm rays of the sun quickly heat up the exterior of the roof – which will typically be constructed of metal sheeting or roof tiles. These materials are very efficient conductors of heat, and in the space of minutes, the heat begins to radiate down into the ceiling or loft space below. Within an hour or two, the ceiling space, which is also poorly ventilated, has heated up to significantly higher than the outside air temperature. As the temperature continues to rise, the difference in temperature between the overheating roof-space and the living areas below – continues to increase. In fact, the only thing slowing down the heat transfer is a thin, hard layer of ceiling lining, which, although not as powerful a heat conductor as a metal roof-sheet – still falls far short of the level of insulation required to stop the heat in its tracks. And it’s not long before the effects are being felt inside the house, with a slow but irreversible rise in air-temperature in all the rooms, in particular those with poor ventilation. At this point, the residents will usually have closed all doors and windows and turned on the air-conditioning, which will remain on until the evening, when the absence of the sun, and a cooling of the outside air temperature will bring relief to the home dwellers once more.
While this is not an exact scientific explanation of exactly how the temperature is ‘transferred’, it does demonstrate a simple reality – insulation batts in the ceiling – especially R4.0 batts and those with an even higher R-Value – are absolutely the main determining factor on how much energy you’ll need to use throughout the four seasons of the year, in order to remain comfortable indoors.

Installing insulation in a tight ceiling space

  • When installing insulation in a ceiling the two most challenging areas to access will typically be the corners of the house, and any rooms that extend beyond the natural contour of the house.
  • The corners: As well as requiring lots of cutting for all the intersecting joists, there are often big support beams in the ceiling that makes access to the corners even more difficult.
  • Extended areas: If the house is a square or rectangle, all the corners will generally have the same pitch of roof. But if there are one or more rooms extending beyond the natural perimeter of the house, these extensions will often have a lower pitch, as well as requiring additional framing, making them less accessible.

Where it’s obvious that it will be difficult, if not impossible, to insulate the entire ceiling area after plaster, you may need to settle for compromise. Install any ‘problem areas’ before plaster, and then load the remaining bags in the ceiling for easy access when climbing up ‘after plaster’ to finish job.