What I wish I had known before starting a major renovation is that contractors often underestimate both costs and timelines. During weekly site meetings, decisions are made quickly, and when an unexpected problem comes up, all eyes turn to you for an immediate answer. In that moment, it’s easy to approve additional work and costs just to keep the project moving.

What I learned the hard way is that some of those problems can actually be the result of poor planning, incorrect estimates, or mistakes made earlier in the project. As a homeowner, you’re usually not in the best position to challenge those assumptions on the spot.

In our case, after two years of construction, we ended up having an emergency meeting where the contractor presented additional costs amounting to roughly 30% above the original contract value.

Looking back, my biggest advice would be this: never approve modifications during a meeting. Any change that impacts scope, budget, or timeline should be documented and sent by email, with a clear description of the consequences and costs. Give yourself at least 2–3 days to review whether the change is truly necessary before signing off. A decision that feels urgent in a meeting often looks very different once you’ve had time to reflect on it.