Wednesday, September 22, 2010

Part 3 - What about wall insulation?

Did you know that wall insulation can affect your star-rating by up to 35%?  Now thatcartoon house's worth looking into further....

We recently rated a double-storey dwelling; walls for both floors were light weight Polystyrene 75mm foam board. The project complied with 5 stars exactly, with ComfortPlus type windows. The client requested to change the ground floor from Polystyrene to brick type. When rated, it did not comply, it was 4.9 stars. We suggested the use of Air-Cell Glareshield foil type or an approved equivalent, giving additional insulation of approx R1.7 to the ground floor walls. Total wall insulation = R2.0 + R1.7 = R3.7. When it was rated, it complied at 5.2 stars.

Good quality foil products can significantly increase insulation performance and improve the energy rating efficiency. They can also be used in roof, giving additional insulation of approx R1.2. Total ceiling/roof insulation = R4.0 + R1.2 = R5.2. For suspended enclosed timber floors, Air-Cell Permifloor 500 or approved equivalent, will give R.3.

For application in apartment buildings, even though each apartment is already thermally insulated and protected by its adjacent neighbours,  adding wall insulation between apartments will be of great benefit. From our experience, this will significantly increase the thermal rating efficiency by approximately 10% - 20%, and provide acoustic benefits as well of approximately 8 - 10 dB(A).

For commercial application, classes 5 - 9, the minimum requirement is a total of R2.3 for concrete / brick type walls. This can be easily achieved by R2.0 insulation batts plus foil and construction material such as plaster, studs, air-gap, etc...  For office internal walls in warehouse buildings, the minimum is R1.8. This can be achieved by R1.5 insulation batts plus foil and construction material such as plaster, studs, air-gap, etc... 

We recently completed an offices development project in Beaconsfield and recommended  Kingspan Koolthem K17 insulated plasterboard panel, R2.8. Refer to photograph depicted. For more information about this product, refer to

When your designing new projects, consider the inherent thermal efficiencies of these wall types, ranked most efficient to least efficient:
  1. Hebal Panels
  2. Polystyrene (EPS)
  3. Brick work
  4. Weatherboard
  5. FC Sheet Cladding
  6. Metal Cladding
Have you found this to make a difference?

Wednesday, September 1, 2010

Does Insulation impact star-rating? Part 2

Insulation, and the impact it has on the star-rating, seems to be the hot topic at the moment. Following on from the previous issue on floor insulation, in this e-newsletter we will be discussing insulation further with a focus on ceiling insulation.

Residential Application – Class 1

(image used with permission from Joe M. Drafting Copyright 2010)

The above is a typical duplex. Unit 1 is double-storey and unit 2 is single-storey. Both units have plenty of north facing windows.

Summary of findings

Unit 1: Ceiling Insulation R3.5; Wall Insulation R2.0; Energy Rating Efficiency 6.0 stars.

Ceiling insulation used between floors. Complies with current BCA 2009 and upcoming BCA 2010.

Unit 1:  Ceiling Insulation R3.5; Wall Insulation R2.0; Energy Rating Efficiency  4.3 stars.

Ceiling insulation only used for upper floor only. Does not comply with current BCA 2009. Few windows will need to be changed to be double-glazed to increase the rating.

Unit 2: Ceiling Insulation R2.5; Wall Insulation R2.0; Energy Rating Efficiency 6.8 stars.

Complies with current BCA 2009 and BCA 2010, from May 2011. Garage internal walls and garage ceiling have been insulated and roof has sarking.

Unit 2: Ceiling Insulation R2.5; Wall Insulation R2.0; Energy Rating Efficiency 6.3 stars.

Complies with current BCA 2009 and BCA 2010, from May 2011. Without garage internal walls, ceiling insulation and sarking.

From the above, it is evident that ceiling insulation between floors will significantly increase the energy rating in an economical way. Additionally, roof sarking, garage walls and ceiling insulation can increase the energy rating by about 0.5 stars. This application is useful now for 5 stars regulation and will add value when 6 stars regulations applies from May 2011.

Insulation for Apartments – Class 2

We have recently completed several multi-level apartment projects. When ceiling insulation is proposed between floors, the energy rating efficiency will generally improve by 10% - 20%. This is significant! A particular 16 apartment project in the inner suburbs of Melbourne, had an average rating of 6.7 stars without using any treated or double-glazed windows! This complies with the current Code of a combined average of 5 stars and the upcoming BCA 2010 (to be applied from May 2011), a combined average of 6 stars.

For further information, feel free to contact our office on 03 9390 2934 or by email You may also wish to visit our website

Kind Regards,

Karim Ghobrial

Electrical Engineer; Energy and Sustainability Consultant