Demand for townhouses in New Zealand is surging. Engineered timber innovation is providing an alternative to standard steel construction while delivering the design flexibility, buildability and cost efficiency developers want – and the space buyers value.

Key takeaways:

• Townhouse design has to optimise space and building efficiency – without compromising structural performance or Building Code compliance. 
• Wide garage openings, open-plan living and larger windows can reduce the wall available for essential ground-floor bracing.
• Prolam’s PLX Portal, PLX Column and SED Columns provide engineered timber alternatives to steel in these applications - spanning wide openings, delivering high bracing capacity within limited wall space and reducing build logistics and timeframes.
• Prolam glulam creates further design opportunities throughout the townhouse, from structural beams and lintels to exterior exposed timber for balconies and pergolas. 
• Potius (now part of the Prolam group) broadens the engineered timber solution with prefabricated floor, wall and roof panel systems suited to multi-unit residential construction.
• Prolam makes the pathway from design to specification and consent easier, with the Prolam Specifier, technical guides, engineering support and PS1 documentation. 

Townhouses are at the heart of New Zealand’s growing medium-density housing market, alongside flats and units, and are rapidly closing the gap in the new-build market. According to Stats NZ, 17,230 were consented in the year to May 2026 – up 22% – compared with 18,271 standalone houses.

For developers, designers and their project teams the challenge is not simply fitting more homes onto a site. It is optimising townhouse design and construction while creating homes people want to live in.

That comes down to the townhouse trifecta:

• Structural compliance. Meeting structural and Building Code requirements for compact, two- and three-storey townhouse designs.
• Space for living. Maximising usable floor area, natural light and indoor-outdoor connection.
• Speed of construction. Using repeatable, buildable solutions that can be efficiently designed, specified and constructed across multiple units.

Get those three working together and the benefits flow both ways: greater building efficiency and stronger returns for developers; more spacious, liveable homes for buyers.

This is where engineered timber innovation is creating new possibilities.

For two-storey townhouses designed within the scope of NZS 3604, Prolam’s PLX bracing systems and engineered timber range provide solutions to structural challenges that have traditionally pushed projects towards steel.

Behind those products is Prolam’s in-house engineering team, working directly with architects or alongside project engineers to help resolve structural design requirements early and provide a clear pathway through design, specification and documentation for building consent. 

And with Potius now part of the Prolam Group, the engineered timber opportunity extends further into prefabricated floor and wall systems for multi-unit construction. 

In this article, we look at where engineered timber fits in townhouse design - from solving wide openings and limited bracing space to the on-site time and cost savings that prefabricated, simple to install bracing and panel systems can unlock. Delivering the structure, space and speed of construction New Zealand townhouse projects demand. 

Where engineered timber works in townhouse designs 

Rethinking townhouse design and construction means looking beyond the default structural approach. The key is matching each design goal or structural requirement with the right engineered timber solution – and understanding where it can replace steel or simplify conventional construction.

Townhouse design goal	Structural challenge	Engineered timber solution
Prolam applications
Maximise garage width within a narrow frontage	Limited wall either side of the opening to achieve the required bracing	PLX Portal — alternative to a steel portal
Create full-width open-plan living	Limited wall length along the bracing line to achieve the required bracing capacity	PLX Column — alternative to additional bracing walls or steel (ground floor only)
Create wider windows and ranchsliders	Large openings reduce the wall available for bracing and require structural support over the opening	PLX Portal / Prolam glulam — alternative to steel
Create wide internal openings	Supporting loads across the opening without intermediate walls or posts	Prolam glulam beams and lintels — alternative to steel beams
Reduce floor beam depth or achieve wider spans	Achieving the required span and capacity within limited floor depth	PLX20 — alternative to conventional framing or steel
Add balconies and outdoor structures	Supporting exterior spans, cantilevers and structural loads	Prolam glulam / Pergola solutions — alternative to site-built timber or steel
Potius applications
Speed up mid-floor or subfloor construction	Creating an efficient structural floor system, particularly where conventional construction is labour-intensive	Potius floor panels — alternative to conventional mid-floor and subfloor construction
Create intertenancy walls	Providing a dedicated wall system between adjoining dwellings	Potius wall panels — alternative to masonry and proprietary panel systems

Download the Quick Guide to Engineered Timber for Townhouses and find out more about the role engineered timber can play in the design and construction of multi-unit residential developments. 

Two-storey townhouse design: three common bracing challenges

The design features that make townhouses more desirable can also make them harder to brace efficiently.

For two-storey townhouses within the NZS 3604 scope, the Prolam PLX bracing range provides engineered timber alternatives to the structural challenges that have traditionally pushed projects towards steel: wide openings and open plan layouts.

At the core of the PLX Portal and PLX Column is market-leading hybrid glulam-steel engineering. A flat steel bar is inserted into the timber laminates to create compact, high-strength glulam members with exceptional load-bearing and bracing capability.

1.    THE GARAGE OPENING

On narrow frontages, the garage door can take up much of the ground-floor frontage. Increasing its width improves access, accommodates larger vehicles and makes off-street parking more practical – but leaves less wall either side to deliver the required bracing.

This is where steel portals have entered the design.

The PLX Portal provides another option: a pre-engineered, high-capacity bracing system that allows the wide opening to remain while keeping the structural solution within timber-framed construction.

2.    THE LIVING-SPACE OPENING

At the other end of the townhouse, the same issue can appear for a different reason.

Large ranchsliders on the lower level and windows on the upper level bring in lighter and strengthen indoor-outdoor connection but also reduce the wall available for bracing.

The PLX Portal can provide bracing around these wider openings on both the ground floor and upper storey. While the PLX Column can also be used on the ground level to support generous glazing and short wall lengths in the entry, kitchen and living areas. 

3.    THE OPEN-PLAN LIVING LAYOUT

In a long, narrow townhouse, open-plan kitchen, dining and living spaces on the ground floor can leave very little wall along a critical bracing line – particularly where the stairwell occupies one side of the plan. The issue is not one wide opening; it is simply running out of wall where the bracing is needed. 

The PLX Column addresses that problem by concentrating high bracing capacity into a short wall length, helping preserve the open-plan layout without adding extra walls or defaulting to steel. 

And because each PLX bracing solution is pre-engineered, prefabricated and designed for straightforward installation, the structural solution is not only easier to resolve on paper - it is also faster and more efficient to deliver on site. 

Prolam PLX vs steel for townhouses: weighing up the costs / benefits

The advantage of PLX bracing range is not simply that engineered timber can do the structural job.

The PLX Portal and PLX Column integrate with timber-framed construction and arrive as prefabricated kitsets, including footplates, ready to install using standard tools and equipment. That means no separate steel fabricator, less reliance on cranes on space-constrained blocks and built-up streets, and no need to pack the structure out afterwards before other trades can continue. 

So, the comparison with steel should not stop at material price.

Upfront material costs can be comparable. The difference often lies in the total installed cost. A YourQS analysis found the PLX Portal represents an 80% time saving and a 24% reduction in total installed cost compared with its steel equivalent. 

It’s a fit, fix and move on solution that works for townhouses according to Alex from Chris Broadhead Construction. Based on his experience on a recent project in Wanaka where the PLX Portal was specified for the garages of an eight-unit complex, he has high praise for its straightforward installation, timber-to-timber connections and time-saving benefits on site. 

Beyond bracing: more opportunities for Prolam engineered timber

The PLX Portal and PLX Column solve the structural situations most likely to send townhouse design towards steel. But engineered timber can work more broadly through the building.

Prolam glulam can be used for beams and lintels across wider openings, the hybrid glulam-steel PLX20 Beam provides a solution for floor beams and joists where a smaller section depth or wider span is required, and visual, H3.2 treated glulam beams and H5 posts can be used for porticos, balconies, pergolas and outdoor structures.

That gives project teams more opportunities to keep the structural approach timber-based rather than introducing different materials element by element. 

Potius: extending engineered timber into floor and wall panels

Potius, now part of the Prolam Group, extends the engineered timber opportunity into panelised construction. Its residential panels are built around LVL timber framing, with plywood or OSB skins and insulation depending on the application, creating lightweight, prefabricated floor, wall and roof systems. 

• Potius floor panels use LVL joists with a plywood skin to create a stressed-skin panel system. Used for mid-floor and subfloor applications, they can significantly reduce erection time, particularly on sloping sites where conventional subfloor construction is slow and labour-intensive. 
• Potius wall panels combine LVL framing with OSB and can be used for intertenancy walls in townhouse developments. 

Together, Prolam and Potius create more opportunities to use engineered timber across the townhouse – from bracing and beams to floors, walls and outdoor spaces.

What changes with three-storey townhouses?

Three-storey townhouse design needs a different structural approach.

Three-storey residential buildings remain outside the scope of NZS 3604 and require specifically engineered design (SED) for lateral bracing.

However, new interim SESOC industry advice provides a clearer pathway for three-storey construction. The ground floor must use SED bracing elements, while the upper two storeys can use NZS 3604-rated bracing elements at reduced ratings, subject to the conditions set out in the interim advice.

For these projects, Prolam offers an SED Column solution that provides high-capacity engineered timber bracing for the ground floor. There is also the opportunity to use NZS 3604-rated PLX Portal solutions on the upper two storeys at the applicable reduced bracing ratings.

Prolam’s in-house engineering team can work alongside the project structural engineer to size and document the solution.

From townhouse design to specification

For PLX Portals and other Prolam structural members:
Use the free Prolam Specifier to perform design calculations, identify suitable Prolam options, and generate supporting PS1 documentation. Or refer to the PLX Portal Design Guide to access technical and design information to confirm the application, capacity, connection details and installation requirements.

For the PLX Column:
Use the PLX Column Design Guide to select the appropriate system and confirm its bracing capacity. PLX Column can then be added to GIB EzyBrace® as a custom bracing element for bracing calculations. The PLX Column is not currently available to be specified using the Prolam Specifier.

For projects that need additional input, including SEDs, Prolam’s in-house engineering team can work directly with architects or alongside the project engineer to provide technical advice, review the design and help identify the right Prolam solution.

Before you default to steel, think engineered timber for townhouses

Wide garages, open-plan living and larger openings are exactly the outcomes townhouse developers and buyers want. They can also be the points where the structure starts heading towards steel.
It no longer has to be the automatic answer.

Planning a townhouse project? 

Talk to the Prolam team early about how engineered timber could fit your design and building needs.

Download the Quick Guide to Engineered Timber for Townhouses and talk to the Prolam team early about how engineered timber could fit your design and building needs.