A Builder's Journey Towards a Healthier Future with His Own Passive House Build

Toby, a Licenced Building Practitioner, Certified Passive House Tradesman and Homestar Practitioner & Assessor, started his building company Craft Homes in 2015. As an Asthma sufferer himself, he knew too well about the negative effects that poor quality housing can have on our health and the cost it imposes on the NZ health system. Thus, he aimed to build a new home that could not only have a positive effect on the health of him and his family, but also to demonstrate to the public what a healthy and sustainable home can look and feel like. The Tilsleys are passionate about helping others improve their health outcomes by building high-performance homes, and make NZs legacy of living in damp, cold and poorly ventilated homes a thing of the past.

As country people at heart, Toby having grown up in the King Country, and Cat in Rural Scotland, they were keen to move their family out of Auckland and reconnect with the country lifestyle. After finding their dream rural section just out of Raglan, the Tilsleys settled on a house design they liked that took advantage of the views and surroundings. SIPs were selected as their construction method of choice. SIPs or Structural Insulated Panels offer a level of prefabrication to the build process, are naturally quite airtight and offer excellent thermal performance values.

The Tilsleys chose to build a certified Passive House, as it would give them a more certain level of health and comfort throughout the year. Passive Houses are thermally modelled during the design stage, have well insulated and airtight thermal envelopes (floors, walls, and roofs), high performing windows and a mechanical ventilation system, all of which helps to maintain an optimal internal temperature and humidity level no matter what the weather is doing. As well as being energy efficient, they decided to generate the little power they would need to operate the house by installing solar panels on the roof, so the house could be self-sufficient from the national grid.

As Toby was building the house himself while managing Craft Homes’ other build projects, he needed to be able to get the envelope of his new house erected, closed in, and kept dry, so he could chip away and finish the house when he had the time, knowing the durability of the envelope wouldn’t be at risk over the wetter months. For this reason, Toby chose to cover the exterior of the Formance SIPs with pro clima SOLITEX EXTASANA ADHERO, a self-adhesive building underlay that is BRANZ appraised for use on roofs and walls. As it is applied without any mechanical fixings, and all laps are well-sealed by the adhesive backing, SOLITEX EXTASANA ADHERO provides optimum weather protection of the building envelope for up to 180 days during construction, while being vapour permeable to allow any residual construction moisture to dry out.

On the internal side, the panel joints and wall/floor junctions were sealed with TESCON EXTORA flashing tape, to ensure the airtightness target required by the Passive House standard could be met, and the SIPs were well-protected from internal moisture ingress. TESCON EXTOSEAL sill tape was used to protect the window openings as per timber framed construction, and any penetrations made through the SIPs were sealed with ROFLEX grommets on both sides of the panel.

After some COVID-induced delays with the build, the Tilsleys are looking forward to finally being able to shift into their new off-grid Passive House and enjoy the healthy and sustainable future that should be the experience for all Kiwi families.

Watch the video “Building Design and Construction” to get insights into the construction methods used in this project and why they were chosen:

Check out the full story on the Craft Homes website

Self Adhesive Building Wrap (SOLITEX EXTASANA ADHERO)

pro clima

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ADHERO is a peel-and-stick weathertightness layer for roof and wall application over a solid substrate.

LBC Red List Free

Appraised (BRANZ Appraisal 989) for use:

Over rigid wall underlays
Over rigid roof sarking
Over roofs and walls of SIP and CLT construction
Specific Design

SOLITEX EXTASANA ADHERO Self-Adhesive Underlay has been appraised for use as a wall underlay over fibre cement and plywood rigid wall underlays on timber and steel framed buildings within the following scope:

the scope limitations of NZBC Acceptable Solution E2/AS1, Paragraph 1.1 with regards to building height and floor plan area; and
with direct fixed absorbent and non-absorbent wall claddings; or
with absorbent and non-absorbent wall claddings installed over an 18 mm minimum drained cavity; or,
with masonry veneer in accordance with NZBC Acceptable Solution E2/AS1 for timber framed buildings or to a specific design for steel framed buildings; and
situated in NZS 3604 Wind Zones up to and including Extra High

SOLITEX EXTASANA ADHERO Self-Adhesive Underlay has also been appraised for use as a roof underlay over plywood roof sarking on timber and steel framed buildings within the following scope:

the scope limitations of NZBC Acceptable Solution E2/AS1, Paragraph 1.1 with regards to building height and floor plan area; and
with roof claddings in accordance with NZBC Acceptable Solution E2/AS1, Paragraphs 8.1 – 8.4; and
situated in NZS 3604 Wind Zones up to and including Extra High

SOLITEX EXTASANA ADHERO Self-Adhesive Underlay has also been appraised for use as a wall and roof underlay when used on buildings within the following scope: p

the scope limitations of NZBC Acceptable Solution E2/AS1, Paragraph 1.1 with regards to building height and floor plan area; and
used on buildings constructed from Structural Insulated Panels (SIPs); or
used on buildings constructed of Cross Laminated Timber (CLT); and
with absorbent and non-absorbent wall claddings installed over an 18 mm minimum drained cavity; or,
with masonry veneer to a specific design for SIP or CLT buildings; and,
with roof claddings in accordance with NZBC Acceptable Solution E2/AS1, Paragraphs 8.1 - 8.4; and,
situated in NZS 3604 Wind Zones up to and including Extra High. (Note: CLT and SIP construction systems have not been assessed and are outside the scope of this Appraisal. See also Paragraph 7.12.)

SOLITEX EXTASANA ADHERO Self-Adhesive Underlay has also been appraised for use over rigid wall underlays or roof sarking on buildings subject to specific weathertightness design. Building designers are responsible for the building design and for the incorporation of SOLITEX EXTASANA ADHERO® Self-Adhesive Underlay into their design in accordance with the declared properties and the instructions of Pro Clima (NZ) Ltd.

Extra High Wind Zone

SOLITEX EXTASANA ADHERO Self-Adhesive Underlay, if used, designed, installed and maintained in accordance with the statements and conditions of BRANZ Appraisal 989, will meet, or contribute to meeting the following provisions of the NZBC:

Clause B2 DURABILITY: Performance B2.3.1 (a), not less than 50 years, B2.3.1 (b), 15 years and B2.3.2. SOLITEX EXTASANA ADHERO Self-Adhesive Underlay meets these requirements. See Paragraphs 9.1 and 9.2. e
Clause E2 EXTERNAL MOISTURE: Performance E2.3.2. When used as part of the roof or wall cladding system, SOLITEX EXTASANA ADHERO Self-Adhesive Underlay will contribute to meeting this requirement. See Paragraphs 12.1 and 12.2.
Clause F2 HAZARDOUS BUILDING MATERIALS: Performance F2.3.1. SOLITEX EXTASANA ADHERO Self-Adhesive Underlay meets this requirement and will not present a health hazard to people.

BRANZ Appraised

Sill Tape (TESCON EXTOSEAL)

pro clima

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Butyl sill tape for use with wall underlays like SOLITEX EXTASANA and SOLITEX EXTASANA ADHERO and other weathertightness layers.

TESCON EXTOSEAL Sill Tape has been appraised as a flexible flashing system for use around window and door joinery openings for buildings within the following scope:

the scope limitations of NZBC Acceptable Solution E2/AS1 Paragraph 1:1; and,
with a risk score of 0-20 calculated in accordance with NZBC acceptable solution E2/AS1 table 2; and,
with wall cladding systems complying with NZBC acceptable solution E2/AS1 or a valid BRANZ Appraisal that specifies a flexible flashing system; and,
with flexible wall underlays compatible with flashing tape; and,
situated in NZ3604 Wind Zones up to, and including, Extra High.

TESCON EXTOSEAL Sill Tape has also been appraised as a flexible flashing system for use around window and door joinery openings for steel framed buildings within the following scope:

the scope limitations of NZBC Acceptable Solution E2/AS1 with regards to the building height and floor plan area; and,
constructed with a steel frame complying with NZBC; and,
with a risk score of 0-20 calculated in accordance with NZBC acceptable solution E2/AS1 table 2; and,
with wall cladding systems covered by a valid BRANZ Appraisal that specifies a flexible flashing system; and,
with flexible wall underlays compatible with flashing tape and steel frame; and,
situated in NZ3604 Wind Zones up to, and including, Extra High.

Used in:

Te Uru Taumatua — Living Building Challenge
Unitec, Weltec and Toi Ohomai student-built homes
Habitat for Humanity
Housing New Zealand

BRANZ Appraised

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