Markham contractors see the same renovation mistakes over and over. Most of them are avoidable — and all of them are expensive to fix after the fact. Here are the seven that cost Markham homeowners the most money, frustration, and time on bathroom renovations.
Skimping on waterproofing
Water damage behind tile is the #1 cause of bathroom renovation failures. Use proper membrane systems — they add $800–$2,000 but prevent $20,000+ in damage.
Buying fixtures before measuring
Always measure rough-in distances before purchasing a toilet. Standard is 12", but older homes vary.
Under-budgeting tile waste
Order 15–20% extra tile for cuts and breakage. Matching tile after the fact is nearly impossible.
Venting the exhaust fan into the attic
Building code requires exterior venting. Attic venting causes mould — and fails inspection.
DIY plumbing in wet areas
Failed plumbing in a bathroom can cause catastrophic water damage. Licensed plumber is non-negotiable.
Ignoring storage in the design
A beautiful bathroom with no storage is a daily frustration. Design in-wall niches and vanity storage from the start.
Cheap grout in a shower
Epoxy grout costs more but lasts 3× longer and resists staining and mould in wet areas.
The Bottom Line
Most of these mistakes share a common thread: they're caused by rushing decisions, skipping steps that seem optional, or choosing cost savings in the wrong places. A bathroom renovation starting at $15,000 is a significant investment. Spending an extra $500–$2,000 to do it right protects the other $15K+.
Use the free Markham Bathroom Calculator to get a realistic budget estimate before talking to contractors — knowing the real numbers prevents many of these mistakes before they start.
Get Your Free Markham Estimate →