Working on a renovation, extension or structural alteration to an existing home? This guide looks at five common New Zealand renovation situations and how Prolam glulam provides a strong, practical and buildable solution. 

Key takeaways:

• Prolam glulam is ideal for the five most common structural renovations, including removing load-bearing walls, home extensions, decks and larger window and door openings. 
• Longer spans and high strength bracing allow for more open-plan spaces and greater design flexibility. 
• The Prolam Specifier helps architects fast-track the selection of glulam beam, post and portals and generate documentation to support the building consent process. 
• Glulam serves as a direct, buildable alternative to structural steel – eliminating the need for specialist steel subtrades, site welding, and crane access by allowing main contractors to install timber framing directly using standard tools.
• Prolam’s engineering team can provide technical advice and specification support throughout your renovation project. 

Across New Zealand, many homeowners are choosing to adapt and extend existing homes rather than rebuild. But adapting and altering existing building envelopes presents unique structural challenges. 

Whether integrating additions into traditional timber framing, converting commercial spaces, or altering residential layouts, achieving design goals depends on solving structural hurdles: load path transfer, bracing requirements, and compliance with Building Code performance standards. 

This guide explains why glulam is suitable for renovations, how it compares with other structural materials and how Prolam can help simplify design, specification, and council consent and construction for the five most common renovation scenarios. 

How does glulam compare to other structural materials?

When planning a renovation, architects, designers and builders often compare glulam with steel or LVL. The best choice depends on the project requirements, but engineered timber offers several advantages in timber-framed renovations. 

Feature	Prolam Glulam	Steel	LVL
Integrates with timber framing	ü  Excellent	Requires steel connections / packing	ü  Good
Long-span capability	ü  Excellent	ü  Excellent	ü  Excellent
Exterior applications	ü  Excellent	Limited	Limited
Weight	ü  Lightweight	Heavier than glulam	Heavier than glulam
Exposed architectural finish	ü  Natural timber appearance	Industrial appearance	ü  Natural timber appearance
Ease of installation	ü  Standard tools	Specialist equipment and installers often required	ü  Standard tools

Why glulam works in renovations

Renovation project teams need to balance design intent, structural performance and construction efficiency.  

That’s where Prolam’s engineered timber solutions give project teams an advantage. Proven glulam products, structural design and specification tools, and practical timber construction help architects, engineers and builders turn even the most challenging renovations into efficient, buildable outcomes. 

Design flexibility

Glulam supports the architectural goals that often drive renovations – open-plan living, wider spans, larger openings, exposed timber features and better indoor-outdoor flow. 

It can be concealed within the structure for a clean finish, or left visible as a warm, natural timber feature. Suitable for both interior and exterior applications (with the right treatment and coating), glulam presents architects with the ability to achieve a consistent design language and whole-of-renovation architectural and structural timber solution. 

Structural performance

Glulam is engineered for predictable strength, stiffness and dimensional stability, making it well suited to renovation work where loads, spans and existing structure all need careful consideration.

In New Zealand, structural alterations must meet Building Code requirements for structure and durability. Prolam glulam provides a reliable timber option for beams, lintels, posts and other structural members where load transfer, bracing and compliance need to be resolved.

Ease of specification

The Prolam Specifier helps architects, engineers and builders quickly evaluate Prolam glulam beam, post and portal options, run design calculations, and generate documentation to support engineering review and building consent.

This helps project teams move from design concepts to suitable product selection faster, with Producer Statements and supporting information available to streamline the consent process.

Buildability 

Renovation sites are often constrained. Access can be tight, existing framing may not match drawings, ceiling heights can be limited and connections to older structures are rarely straightforward.

As an engineered timber product, glulam works well within timber-framed renovation projects. It can be specified in a wide range of standard and custom sizes, easily connected into existing timber framing, and, where appropriate, trimmed on site for a more accurate fit.

This makes glulam a practical option for reducing onsite complexity and total installation costs, while still meeting the structural requirements of the renovation. In many situations, it can also be easier to handle and install than steel, with less packing around, reliance on specialist fabrication, or additional installation equipment such as hiabs or cranes.

Five renovation situations where Prolam glulam provides a solution

1.    REMOVING INTERNAL AND LOAD-BEARING WALLS

The design goal

Create open-plan living by removing walls between kitchens, dining rooms and living areas. 

Key considerations

• Is the wall load bearing?
• What loads need to be transferred once the wall is removed?
• Where will the new loads be supported?
• Are new point loads being introduced?
• Will bracing be affected by removing the wall?
• Will the new members be concealed or left exposed?

Prolam glulam solutions 

• Glulam beams can replace the structural role of a removed load-bearing wall by spanning across the new opening and transferring loads to suitable supports. 
• Lintels may be used where smaller structural openings are created or altered.  
• Visual grade glulam beams can turn the structural beam into an architectural feature. 
• PLX Portal and Column solutions may assist where wall removal affects bracing or where compact bracing is needed.
• PLX20 Beams can deliver a timber-based structural approach for spans that sit beyond standard glulam beam options or solid timber. 

2.    HOUSE EXTENSIONS AND EXPANDED LIVING AREAS

The design goal

Increase floor areas, expand living spaces, add bedrooms, extend kitchens, with a focus on optimising the connection and flow between the original home and a new addition.  

Key considerations

• What new roof, wall or floor loads are being introduced?
• Are longer spans required?
• Are new large openings part of the extension?
• Will existing foundations and supports be adequate?
• Are there opportunities to expose timber as part of the design?

Prolam glulam solutions 

• Glulam beams, lintels and posts can support new loads created by additions and extensions.
• Ridge beams, rafters and exposed trusses can support new roof forms, vaulted ceilings or architectural timber features.
• PLX Portals can provide bracing requirements where extensions include large openings or limited wall space.
• PLX20 beams can provide a glulam-steel hybrid option that spans longer with similar sized members. 
• Visual grade glulam beams, posts and exposed trusses allow structural members to become part of the finished architectural expression.

3.    DECK ADDITIONS AND OUTDOOR LIVING AREAS

The design goal

Create or extend outdoor living spaces, including decks, covered alfresco areas, pergolas, verandas and poolside entertaining zones. 

Key considerations

• What live loads will the deck or outdoor structure need to support?
• Is the deck elevated or attached to the existing house?
• What are the footing, post and bearer requirements?
• What exposure and durability requirements apply?
• Is the structure covered or uncovered?
• Will the timber be visually expressed?

Prolam glulam solutions 

• Glulam beams and posts support larger spans provide structural stability and bracing for decks, pergolas and covered outdoor structures.
• Pergola, veranda and rafter beams can support covered outdoor structures while keeping the design timber-based.
• CodeMarked H5 glulam posts are suitable where in-ground durability is required.
• Visual grade glulam can provide both structural support and be oiled, stained or painted to provide a warm architectural finish for outdoor areas.

Due to the strength, spanning and load-bearing capacity of glulam beams and posts, fewer structural members may be required in some deck or outdoor applications, helping create more open spaces and maximise the outlook. 

4.    CHANGING THE FUNCTION OF ROOMS

The design goal

Re-purpose existing spaces into more useful living areas, such as converting a garage into a bedroom, office, studio or additional living areas. 

Key considerations

• Is the structure suitable for the new use?
• Are new windows, doors or openings being added?
• Are existing garage openings being closed in, widened or altered?
• How will bracing be affected?
• Are new beams or lintels required?
• Are there consent or compliance requirements triggered by changing the function of the space?

Prolam glulam solutions 

• Glulam lintels and beams can support new or altered openings.
  
• Posts and beams can help transfer loads where the existing layout is being changed.
  
• PLX Portals may assist where garage openings, large windows or limited wall lengths create bracing challenges.

Glulam helps the existing structure meet the needs of the new layout and function, while keeping the solution practical for timber-framed construction.

5.    REPLACING AND ENLARGING AGEING JOINERY

The design goal

Replace older windows and doors with larger sliders, bi-folds, picture windows or wide openings to improve light, views and indoor-outdoor flow.  

Key considerations

• How wide is the new opening?
• What loads sit above the window or door?
• Is the existing lintel adequate?
• Is the existing bracing design affected?
• Are support points and fixings suitable?
• Is the desired opening pushing the project beyond standard framing solutions?

Prolam glulam solutions 

• Prolam lintels can support larger window and door openings where existing lintels are no longer adequate.
• Glulam beams can help achieve wider spans while keeping the structure timber-based.
• PLX Portals may help where larger openings reduce available bracing wall length.
• PLX20 Beams can help where the required span is beyond the capacity of standard beams.
• Visual grade glulam can provide both structural performance and architectural character where the lintel or beam will remain exposed.

How to specify Prolam glulam for renovations

For renovation work, early specification of structural timber solutions helps align the architectural intent, structural requirements and practical realities of alterations to an existing New Zealand home.

Start by confirming what the renovation is trying to achieve, and what that means structurally. Consider the span, loads, bracing requirements, support points, exposure conditions and treatment requirements. 

For common structural timber applications, the Prolam Specifier accelerates the design process – allowing designers to perform calculations, identify Prolam product options, and generate documentation to support engineering review and council consent requirements such as Producer Statements. Prolam’s Specific Engineering Design Guide also provides access to span tables and data to assist with calculations for more complex structural requirements.  

The Prolam team is also available to provide technical support, including reviewing plans and helping to identify suitable Prolam products for the application.

It is always recommended that you seek the support of a qualified structural engineer for structural renovations to help finalise a design in advance of any engineering sign-off or building consent processes. 

Renovate with confidence with glulam

Renovations are about making an existing home work better – more space, more light, better flow and stronger connection to the way people want to live.

But behind every open-plan layout, wider opening, extension or deck is a structure that needs to perform.

Prolam glulam gives architects, designers, builders and engineers a practical engineered timber option for structural renovation work across New Zealand. 

Use the free Prolam Specifier to explore suitable glulam options for your next renovation project or get in touch with the Prolam team to discuss your project needs.