Unconsented Building Work: How We Spot It During a Building Inspection and What It Means

TL;DR (40–60 words): Inspectors can often identify unconsented building work by mismatches between what’s built and the consented plans. It can impact insurance, resale and compliance. We’ll show you the tell-tale signs, what to request from the seller, and realistic pathways to tidy things up.

Unpermitted alterations are common: garages turned sleepouts, internal wall shifts, extra bathrooms, decks or pergolas that quietly “appeared”. Our job is to spot indicators of possiblly unconsented building work and explain the implications.

Unconsented building work: signs we look for

• Typical design: Often older homes, i.e., 1970s bungalows, are more compartmentalised by design. When we come across very open-plan layouts in older era homes, it's a strong indication that there has likely been an internal wall alteration.
• Plan vs reality: Room layouts, window/door positions, wet-area locations and structural walls that don’t match consented or original drawings.
• Services clues: New plumbing/vents without corresponding consent documentation, plumbing fixtures in locations that arent typical.
• Structure: Lintels or beams added/removed.
• Materials timeline: Mixed-era linings, claddings, structural elements, timber and fixing types.

Why it matters

• Insurance: Some policies may exclude damage linked to unpermitted work.
• Resale: Buyers and banks get nervous; valuation can be affected.
• Safety: Hidden defects in waterproofing, structure or wiring create real risk.

Your options if we find it

• Talk to Council early: For eligible historic work that’s safe and accessible, a Certificate of Acceptance (CoA) may be possible. Not all work qualifies.
• Get evidence: As-built drawings, producer statements, photos during construction—anything that proves how it was done.
• Prioritise hazards: Fix safety issues (e.g., live wiring, non-compliant balustrades) regardless of paperwork.
• Negotiate: Price, scope of remedy, or vendor obtaining approvals post-settlement.
• Demolition or removal: Sometimes if an illegal structure has been built to a subpar standard the best course of action is professional removal or demolition.

Due diligence tips for buyers

• Request the LIM and full property file; compare plans to the physical house.
• Walk the site with the drawings and note discrepancies.
• Keep changes in perspective—some are minor and regularisable; others are risky and expensive.

Bottom line: Identifying unconsented building work early gives you choices—tidy it now, price it in, or walk away.