How to Tell If a Wall Is Load Bearing: Melbourne Guide

A load bearing wall carries the weight of the structure above it (roof, ceiling or upper floor) and transfers that load down to the footings. Removing or cutting into one without an engineered replacement can cause sagging ceilings, cracking and, in severe cases, partial collapse. This guide explains the practical checks a Melbourne homeowner can make, how those checks differ between common Melbourne house types, and why a structural engineer's confirmation is still required before any wall comes out.

What Is a Load Bearing Wall?

A load bearing wall is any wall that supports load beyond its own self weight. In a house this usually means roof load (through struts or ceiling joists), upper floor load (through floor joists) or a concentrated load from a beam or post above. Non-load bearing walls, often called partition walls, divide space but carry nothing from above.

There is a third category that homeowners often miss: the bracing wall. Under AS 1684 (Residential timber-framed construction), certain internal and external walls are sheeted and fixed to resist wind racking forces. A bracing wall may carry no vertical load at all, yet removing it can reduce the building's resistance to wind. A structural engineer checks for both roles.

Five Checks to Tell If a Wall Is Load Bearing

The following checks are the same ones a structural engineer starts with. Work through them in order and note what you find. The results will not replace an engineer's assessment, but they make the site visit faster and more focused.

Checking the Roof Space Safely

The roof space gives the clearest evidence in a single storey home. Step only on ceiling joists, never on the plasterboard between them, and watch for exposed electrical cabling. In a conventionally pitched (stick built) roof, look for vertical or angled timber struts running from the rafters or underpurlins down to a wall plate. If a strut lands on the wall you are considering, that wall carries roof load. Large timber members running along the top of ceiling joists (hanging beams) that bear onto a wall are another clear sign. In a trussed roof, the triangulated trusses usually span from one external wall to the other, and internal walls below are often non-load bearing, although girder trusses and truss support points can still land on internal walls.

Obtaining the Original Drawings

For houses built with a building permit, the council that holds the property's building records can usually supply copies of the permit drawings through a building information or document request. Newer homes may also have plans held by the original builder or included in the sale documents. Older Victorian and Edwardian homes rarely have useful drawings, so the physical checks above carry more weight.

How the Checks Differ in Common Melbourne House Types

Melbourne's housing stock spans more than a century of construction methods, and the typical load path changes with the era. The table below summarises what a structural engineer expects to find before the inspection.

Visual Indicators Homeowners Can Check

Beyond the five checks, the following signs suggest a wall may be load bearing. Treat them as prompts to seek engineering confirmation, not as a substitute for it.

• The wall runs perpendicular to the ceiling or floor joists and the joists rest on its top plate
• The wall runs along the centre of the house, parallel to the roof ridge (the classic central spine wall)
• The wall lines up with a wall on the floor above in a double storey home
• The wall is solid brick, double brick or concrete block rather than lightweight framing
• The wall is external, or used to be external before an extension was added
• There are posts, columns or steel sections within or next to the wall
• The ceiling has cracks or a slight sag running along the line of the wall

Common Misconceptions About Load Bearing Walls

"If the wall is plasterboard, it is not load bearing"

Not true. Many load bearing timber stud walls in Melbourne homes are lined with plasterboard on both faces. The lining says nothing about the framing behind it or the wall's position in the load path.

"The builder said it is fine to remove"

A builder can give a practical view, but a building surveyor issuing a permit for the removal of a structural wall will require engineering documentation. Removing a wall without that sign off creates a liability for both the builder and the owner.

"Internal walls under trusses are never structural"

Trusses usually span between external walls, but girder trusses, truss support points and bracing requirements can all land on internal walls. Removing an internal bracing wall without replacement bracing can reduce the house's resistance to wind.

"The house has not moved, so the wall cannot be load bearing"

The house has not moved precisely because the wall is doing its job. Removing it changes the structural conditions immediately.

What Happens If a Load Bearing Wall Is Removed Without Engineering Input

Rectifying an unauthorised removal usually involves temporary propping, a retrospective engineering design and a permit, and repairs to finishes. The disruption and cost almost always exceed what a planned, engineered removal would have involved.

When to Call a Structural Engineer

A structural engineer should assess the wall before any removal or new opening where:

• Any of the five checks above point to the wall being load bearing
• The house is double storey, or the wall is below a roof with struts
• The wall is brick, double brick or concrete block
• The wall runs through the centre of the home parallel to the ridge
• A building surveyor or builder has asked for engineering documentation
• Previous renovations have altered the roof or floor framing

Principal Built Engineering provides structural engineer inspections and load bearing wall assessments across Melbourne. Where removal is proposed, the engineer confirms the load path, designs the replacement steel or timber beam, specifies the posts and footings, and prepares the documentation needed for the building permit. PBE's fee is quoted to the scope of each job (the number of walls, the opening size, the loads carried and whether beam design and permit documentation are needed), and the site inspection is included in that fee. For the factors that drive engineering fees, see the structural engineer costs Melbourne page. A formal written outcome can also be provided as a structural engineer report.

Frequently Asked Questions

How do I know if a wall is load bearing?

Check whether it is an external wall, whether ceiling or floor joists run across and rest on it, whether struts or beams in the roof space bear onto it, and whether another wall sits directly above or a bearer runs directly below. These checks indicate likelihood only. A registered structural engineer must confirm the wall's role before it is removed or altered.

Can a structural engineer tell me if a wall is load bearing?

Yes. A structural engineer inspects the wall and the visible and safely accessible structure around it, reviews any available drawings and provides a written determination of the wall's structural role. This is the assessment a building surveyor relies on when issuing a permit.

Are internal walls load bearing in a house with roof trusses?

Often not, because trusses usually span between the external walls. However, girder trusses and truss support points can bear onto internal walls, and some internal walls are bracing walls that resist wind loads. An engineer checks both before an internal wall is removed.

Which direction do joists run over a load bearing wall?

Joists that run across the wall at 90 degrees and rest on its top plate, or join over it, indicate the wall is supporting them. Joists that run parallel to the wall generally indicate it is not carrying that floor or ceiling, although roof struts may still bear onto it.

How much does a structural engineer charge for a load bearing wall assessment?

The fee depends on the number of walls assessed and whether the scope includes beam design, calculations and permit documentation. Principal Built Engineering provides a fixed-fee quote before the site visit is booked.

To confirm whether a wall in your home is load bearing, request a quote from Principal Built Engineering. PBE serves homeowners and builders throughout greater Melbourne.