| Clarification Type |
Tool Version |
Month Released |
Credit Name |
Tool Category |
Amendment/Approved Ruling |
|
V4.1
|
October |
|
WST
|
The TQ requesting 3 Points for WST-1 based on total onsite waste sent to landfill (kg per m2 of site) is within 10 kg/m2 although no quantification is available for waste generated during offsite construction, is accepted. To be clear WST-1 in Homestar v4.1 (which this project is registered under) only accounts for waste generated on site, as waste from offsite assembled components are often difficult to quantify, AND reporting from overseas* suggest that offsite construction helps significantly reduce waste from construction. Hence this project is eligible for points to be awarded solely based on waste generated onsite.
|
| Project Specific |
V4.1
|
October |
|
EHC
|
Bedrooms are calculated on the square footage area of flooring of the actual room to determine compliance for EHC-7 Natural Lighting. The Master bedroom is most often the largest room, however a room that has more adjoining facilities like ensuites and walk-in wardrobes would likely be treated as the master bedroom despite a smaller habitable floor area. In terms of achieving compliance, we accept the Master bedroom as the smaller room with adjoining facilities.
|
|
V4.1
|
October |
|
MAN
|
Homestar approves CPTED and surveillance camera system with appropriate lighting as an alternative for the MAN-1 credit. Homestar cites CPTED in MAN-1 and they are good guidelines.
|
|
V4.1
|
October |
|
EHC
|
It is a requirement for habitable spaces to have a reliable and practical means of ventilation and in this case, the project seeks to use the intermittent extract pathway which means reliance on passive ventilation for habitable spaces. Therefore, having the slider as the only source of ventilation can be problematic for a space that is a kitchen, dining, and living area. Because while the slider can be very useful during the day in the summer when the space is in use and/or occupied this may not be the casein the winter. Furthermore, leaving a sliding door open at night in any dwelling raises security concerns. In the case of a care/retirement facility, it can leave both staff and residents feeling unsafe. Hence, the slider is likely to be closed. Thus, NZGBC advises the project to seek alternative means of compliance by considering a ranch slider with an awning window. This also gives building occupants/users control over their space.
|
| Project Specific |
V4.1
|
|
EHC1 - Thermal Comfort
|
EHC
|
The request to use the Cresco Waffle Suite Software to calculate the R-value of the R-value of the Firth Xpod Foundation system (Plastic Dome / air void spacer) in place of using the ‘Generic Slab / solid concrete foundation’ as per the Homestar V4.1 Manual page 197 which states "If the core is air-filled, treat as if solid concrete’ is denied. The Cresco website states that “Wafflesuite™ is a software that runs calculations of waffle rafts in compliance with AS2870 Appendix F.” [1] and the Australian standard website states that AS2870 Appendix F - (informative) deals with the soil structure interaction analysis for stiffened rafts. This is structural engineering software rather than thermal modelling software and it is unclear if this software can calculate ground temperatures from slab geometry or uses ISO13370 to estimate ground impacts on heat loss or accurately model 3D heat loss in accordance with EN ISO 10211. Whilst the Wafflesuite calculation methodology does include reference to ISO13370 in section 5 on page 27 it merely states that “a layer of coarse-grained compacted engineered fill that is placed immediately under a waffle raft foundation may be modelled in a thermal analysis conducted in in accordance with ISO13370” not that this modelling has actually been undertaken in accordance with ISO13370. The reference to ISO 6946 is in section 5.2 on page 28 and states “when foil insulation is used, the compliance with building code is demonstrated via an alternative solution (ISO6946)”. Again not that modelling of the specific product has occurred in accordance with this ISO standard. In addition foil insulation is banned for use in New Zealand. [1] https://www.cresco-group.com/driving-innovation/
|
| Project Specific |
V4.1
|
|
|
|
An exemption beyond 31st January 2026 can be arranged under extenuating circumstances. This must be confirmed in writing by NZGBC. Updates to the building code (specifically H1 5th edition), finalised in November 2023 will require insulation levels to match or exceed the insulation requirements of Homestar v4.1 for heat loss. However the ventilation requirement of the building code have not changed, nor is there any requirement to consider the risk of overheating. In order to manage the reputational risk to Homestar, to incentivise improved design where possible, and to inform home occupants, NZGBC requires the following as a condition for granting an extension to the submission date of Homestar v4.1 projects: 1. A risk assessment of overheating is to be carried out. This should be done in accordance with CIBSE TM59, or similar. 2. The submission must included a summary report of the overheating risk assessment. The report should also include any planned or possible mitigation measures. Project teams are reminded that projects may be upgraded to Homestar v5 at any stage prior to submission, at no additional cost. Every effort should be made to fulfill the performance objectives of Homestar v5, which may include the application of further TQs.
|
| Project Specific |
V4.1
|
|
EHC9 – Sound Insulation
|
EHC
|
NZGBC allows 5 dB difference provided the ASTC ( Performance measured in the field) is not more than 5 dB below the STC58 (Performance of a system in the laboratory). In your case, the specified IT wall system has an STC rating of 58, while the field test resulted in an ASTC rating of 53. A difference of 5 points between the specified rating and the field test result is not uncommon and may fall within acceptable tolerance levels in many cases. NZ Building Code specifies that walls and floor/ceiling assemblies must achieve a Sound Transmission Class rating of at least STC 55 in laboratory. A 5 point leeway is permitted on site, so that the minimum requirement on site is ASTC 50 (Field Sound Transmission Class).
|
| Project Specific |
V5
|
October |
HC1 - Winter Comfort
|
HC
|
100% heating by the heat pump installed in the living area is accepted considering a combination of the set criteria below has been met. • Highly insulated envelope • Ducted Ventilation • Thermostats in separate rooms with direct control to heat pump • Heating demand of total conditioned space relative to the capacity of the heat pump The heat transfer aspect is being satisfied due to the heat pump heating capacity, its auto -functionality along with high-performing envelope and ventilation equalizing the overall house temperature on a constant basis.
|
| Project Specific |
V5
|
October |
HC1 - Winter Comfort
|
HC
|
|
|
V5
|
|
EN2 - Embodied Carbon
|
EN
|
This is a broad guide for what to include when accounting for (custom) materials in the Homestar Embodied Carbon Calculator (HECC). When all materials in the “must include” section are included, it is estimated that 95% of the total embodied carbon for the most common construction assemblies in New Zealand will be accounted for. Must Include Walls : Cladding Structural framing Internal linings (e.g., GIB) External paint (e.g., applied to weatherboards, if included) Internal paint Cavity Battens Insulation Roofs: Cladding Structural framing Ceiling lining Internal paint Insulation Purlins Suspended Timber Floors: Flooring Structural framing (joists, bearers, piles) Pile footings Subfloor linings. Insulation Concrete Slabs: Concrete (slab and footings) Reinforcing steel Basecourse/fill Underslab insulation (e.g., EPS) Edge protection Membranes (e.g., DPC) May Exclude : Internal paint applied to cornice and skirting. Exterior primer Cornice Interior primer Cavity vent strips Building wrap Skirting Fixing straps Adhesives Fixings Interior primer Building wrap Adhesives Fixings Membranes Adhesives Fixings Sand blinding Flashings Edge insulation Formwork Accessories to slab (e.g., bar chairs, wire) Adhesives
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