Anyone who has renovated will tell you: there’s the renovation you imagine, and the renovation you live. Between the two there’s often a gap dug by a few avoidable mistakes. After more than 20 years leading residential and commercial projects in Quebec, we’ve seen the same pitfalls come back again and again. Here are the seven most common renovation mistakes — and, above all, how to avoid them.
1. Underestimating the budget
This is mistake number one, by far. People set a budget based on Pinterest and three quick quotes, and forget about surprises. Yet in renovation, surprises aren’t the exception — they’re the rule. Vermiculite, aluminum wiring, a French drain to redo, weakened framing: every wall you open can reveal a new bill. It’s one of the costliest renovation mistakes.
The golden rule: plan a contingency reserve of at least 15 to 20% of the total budget. On a $100,000 project, that’s $15,000 to $20,000 set aside so you never have to stop the job halfway.
2. Hiring a contractor without an RBQ licence
In Quebec, any contractor performing construction or renovation work must hold a valid licence from the Régie du bâtiment du Québec (RBQ). Yet homeowners still get caught every year by unlicensed operators who offer an unbeatable price… and disappear as soon as a problem shows up.
An RBQ licence isn’t a decorative piece of paper. It confirms that competencies have been verified and that the contractor holds a licence bond ($40,000 for a general contractor) that can compensate the client in certain situations, such as work that was never done or done poorly. Always check the licence on the RBQ website before signing.
3. Skipping the required permits
Many homeowners think a small addition or new windows don’t require a permit. That’s false in most Quebec municipalities. Working without a permit exposes you to fines, problems at resale, a refused insurance claim, and even an order to demolish.
Before you start, visit your municipality’s planning department. Five minutes at the counter can save you years of trouble.
4. Poor coordination between trades
The plumber finishing before the electrician has come through. The tile setter arriving before the mortar bed has cured. The painter painting walls that are still damp. Poor coordination means rework, delays and extra costs.
That’s exactly why you hire a general contractor: to orchestrate the sequence and keep subcontractors on track. If you coordinate yourself, be ready to spend 20 hours a week on the phone.
5. Choosing on the lowest price alone
Three quotes, you take the cheapest. Logical? Not always. An unusually low quote often hides something: lower-quality materials, uninsured subcontractors, steps left out of the estimate, or worse — a contractor planning to cut corners to stay profitable. The lowest price often hides other renovation mistakes.
Compare quotes in detail. If one is 20% lower than the others, ask questions. Request the exact list of materials, brands and thicknesses, and whether final cleanup, permits and taxes are included.
6. Not putting anything in writing
A handshake looks great in old movies. In renovation, it’s risky. A written contract should state the total price, schedule, payment terms, materials, exclusions, late penalties and the procedure for changes during the job.
Without a clear contract, if there’s a dispute, you’ll be alone in front of a judge trying to prove what was promised. A good contractor will never refuse to put things in black and white.
7. Ignoring hidden structural problems
Many clients want to jump straight to the finishes: a new kitchen, paint, flooring. But if the building envelope is compromised — an aging roof, poor insulation, a cracked foundation — all those beautiful finishes will age prematurely. Of all renovation mistakes, it’s often the hardest to undo.
Money invested in the structure and envelope pays back more over time than money spent on decor. Always have the hidden elements assessed before planning the visible ones.
Avoiding renovation mistakes: how to start on the right foot
A successful renovation begins before the first hammer swing: with a licensed contractor, a clear contract, a realistic budget and a detailed plan. At MSC Construction, we take the time for this preparation because we know it prevents the vast majority of problems we see elsewhere. It’s less glamorous than a great before-and-after photo, but it’s what separates a satisfied client from a traumatized one.
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MSC Construction handles new homes, extensions and major renovations and commercial projects across Quebec. Tell us about your project: request your free quote.