Project Description



Construction cost was reduced by keeping existing walls from new works (insulation). This was done by decreasing averaged U value from 4.4 to 3.7 and by adding 100% less insulation to the walls and 125% more insulation to the ceilings.

Existing commercial (class 9b) is located in the city of Tyabb. With new extension to the existing building, it consists of 1 levels with net conditioned area of ?m2.

Through JV3 method we managed to keep the existing walls from new works (adding insulation).

Here are some more details on the degree of insulation and glazing thermal performance for the Tyabb project:


Item NCC 2019 Reference Building Proposed Building
Floor No insulation added to concrete slabs on ground,
Solar absorbance 0.6
As per reference case.
Internal and common walls No insulation added to the timber stud walls

As per reference case

External walls R2.24 added to all external walls,
Solar absorbance: 0.6  

No Insulation added to external cavity walls, Total R-Value: R0.5

Roof/Ceiling R2.66 added to the pitched roof (23 degrees) with 2.4m high plasterboard ceiling
Solar absorbance: 0.7
Insulation with R-Value of R6.0 added to all ceiling,
Total R-Value: R6.36Insulation with R-Value of R6.0 added to all cathedral roofs
Total R-Value: R6.42
solar absorbance: 0.48
External shading All adjoining structures and features, window shading and shading devices have been incorporated into the analysis based on available drawings

As per reference case.

Glazing All south-west facing windows:
U-Value: 3.3, SHGC:0.66All south-east facing windows:
U-Value: 4.4, SHGC: 0.54All north-east facing windows:
U-Value: 5.5, SHGC: 0.43All north-west facing windows:
U-Value: 5.5, SHGC: 0.30Skylights:
U-Value: 4.0,  SHGC: 0.53
All windows and doors total performance:
U-Value: 3.63, SHGC: 0.58D03 and D05:
U-Value: 3.8, SHGC: 0.53

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