Signs a builder isn't equipped for structural work

You've met with a builder about adding a second bedroom and they've given you a quick quote over WhatsApp. They're keen, their price is lower than two competitors, and they say they can start in three weeks. But something feels off — maybe they were vague about the foundations, or they didn't ask about soil conditions, or they glossed over how the new roof ties into the existing structure.

That unease is worth trusting. Structural work—the bones of an addition—is where shortcuts and inexperience cause problems that surface months or years later: cracks, uneven settlement, water ingress, or worse. Knowing what to look and listen for now prevents costly remediation and safety risks later.

Red flags during the site visit and conversation

A builder equipped for structural work will spend time on site before quoting. They'll walk the perimeter, ask about the age of the house, the soil type, whether there's a damp course, and how the existing roof is constructed. They're gathering clues about what they're tying into.

If a builder rushes the site visit, sketches dimensions in five minutes, or says "it's all straightforward," that's a warning. Structural decisions depend on specifics: a Johannesburg home on rocky ground behaves differently from a Cape coastal property on sandy soil. A 1980s brick veneer home has different constraints than a 1950s double-brick structure.

Watch for builders who avoid technical questions or deflect with "don't worry, I've done hundreds." Experience matters, but so does curiosity about your particular house. Red flags also include:

• Not asking about site drainage or whether water pools near the foundation after rain
• No mention of temporary bracing or support during construction
• Dismissing the need for council approval or structural drawings as bureaucratic hassle
• Unable to explain why the extension's foundation depth or concrete specification matters
• Unwilling to discuss what happens if they hit unexpected conditions (rock, old fill, services) once work starts

A builder who's uncomfortable saying "I'll need to check that" or "I'll get a structural engineer to advise" is signalling they don't know their limits.

How the work itself reveals gaps

Once construction starts, a structurally competent builder leaves visible markers of care. The foundation is dug to the specified depth and inspected before concrete goes down. Concrete columns or brick piers are plumb and level—not visibly wonky. Roof trusses or beams are seated firmly and anchored properly, not resting casually on a brick ledge. Wall ties between old and new masonry are visible and spaced correctly.

If you visit the site and see excavation that looks arbitrary, concrete poured without formwork or inspection, or roof timber that seems to be held in place by habit rather than engineering, stop the work and get a second opinion. Don't wait for the job to finish.

Another tell: a builder who resists your questions or site visits during construction, or who avoids having a structural engineer inspect the work at key stages. If the contract included engineer sign-off (which it should for significant additions) and the builder is making excuses about why the engineer "hasn't been needed yet," that's a problem.

An ill-equipped builder may also cut corners that aren't visible until later: inadequate lintels over new openings, roof loading spread unevenly, new walls not properly bonded to existing ones, or flashings installed incompletely. By then you're living with the consequences.

Getting ahead of it

The best protection is to check their track record before you hire. Ask for references from three recent structural additions and visit them if you can. Ask the previous owner: did any cracks appear after the work? Is the roof leaking? Has the floor settled unevenly?

Also ask the builder directly: where do they typically hire a structural engineer? Can they name one? Do they have a relationship with a local surveyor for foundation inspections? Builders who work regularly with engineers and inspectors have systems in place. Those who don't are flying blind.

When you're ready to hire, get quotes from builders who take time on site, ask thorough questions, and can explain the structural logic of their approach—not just the timeline and price. On Strove, you can review builder profiles, see their work, and read feedback from other homeowners who've already spotted the difference between a builder who knows their trade and one just guessing. That due diligence upfront saves heartache and money later.