Small in footprint, but big on performance these two off-grid cabins use Prolam glulam to deliver strength, open interiors and smart prefabricated construction.      

When David and Jenna Hartly decided to add self-contained accommodation to their rural Hapuku property, they turned to Cosy Cabins who specialise in in modular tiny and portable homes that are built off-site and delivered across New Zealand.

Justin McLean and the Cosy Cabins team created two stand-alone dwellings for the property – a 48m² two-bedroom Cosy48 and an 18m² one-bedroom Cosy18 – each custom designed to meet the Hartleys’ brief for practical yet luxurious spaces that make the most of the site, views and sunlight.

Both are fully off-grid, with solar, battery, tank water and septic systems, and were built in Motueka before being transported to Kaikōura.

At first glance, the cabins have a simple, understated form. Step inside, though, and there’s more than meets the eye. Clever use of timber creates interiors that feel warm, open and generous, while working hard structurally behind the scenes.

Despite their modest scale, the cabins had some significant structural demands to meet. The exposed site sits in an Extra High wind zone and Snow Zone N3, placing significant loads on the pitched roof structure and making the right engineered timber solution critical.

Small footprint. Smart structural design. 

In the larger two-bedroom Cosy48 cabin, and the one-bedroom Cosy18 cabin, a 28-degree pitched roof and raked ceiling add height and volume to the living areas, with the exposed Prolam ridge beam helping define the open interior. 

The Cosy48 features a 360 x 90mm PL12 ridge beam spanning 6.0 metres, while the smaller Cosy18 has a 240 x 90mm ridge beam with a 4.7-metre span. Prolam 140 x 90mm lintels were also used to support the ridge beams and wide door and window openings.

As Justin explains: “Glulam gives us beams engineered for the exact load we need but are still light enough and straightforward to work with in an off-site build.”

Built in Motueka. Made for Kaikōura.

Prefabrication was central to the construction approach. 

Both cabins were built at Cosy Cabins’ Motueka facility before being transported to Hapuku, craned into position and placed on piles. Building off-site gave the team greater control over construction and reduced the amount of work required on the exposed site. 

For Justin, Prolam glulam is a natural fit for the straightforward construction that defines the Cosy Cabins building philosophy.

“Glulam is lighter than steel and easier to handle, and we don’t have welding or coating touch-ups to deal with. For the way we build, it just works,” he says. 

The consistent dimensions and straightforward timber connections also suited Cosy Cabins’ practical, repeatable construction method. 

Large windows and doors connect the interiors with decks and the surrounding landscape, helping both cabins make the most of their setting. 

Support from design to delivery

The Cosy Cabins team used the Prolam Specifier to size the glulam members for the project and generate the supporting producer statement.

Having ready access to the engineering and documentation needed to progress a project is a key advantage for Justin:

“Engineering, product selection and the producer statement come out of one tool, which keeps consent documentation moving on a tight programme.”

Cosy Cabins is a regular Prolam customer, located just minutes from Prolam’s Motueka manufacturing facility. Justin says the responsiveness of John Woodman and the Prolam team, together with reliable supply, are an important part of that ongoing relationship.

“Prolam works really well for the way we build. The glulam is consistent and straightforward to install, the Specifier brings engineering, product selection and documentation together, and the team is responsive and reliable. This helps us keep projects moving from design through to delivery.” — Justin McLean, Cosy Cabins

Get the look

Cabin 1

• Size: 48m2
• Ridge Beam – 360 x 90mm Prolam PL12 Beam
• Span: 6.0m span
• Treatment: H1.2

Cabin 2

• Size: 18m2
• Ridge Beam – 240 x 90mm Prolam PL12 Beam
• Span: 4.7m span
• Treatment: H1.2

Both Cabins

• Lintels over door and window openings
• 140 x 90mm Prolam PL12 Beams 
• Treatment: H1.2

Design tools and support

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Images courtesy of Cosy Cabins.