DIY home repair videos make everything look manageable. But some jobs carry real consequences if done wrong — safety hazards, insurance voidance, failed inspections, or damage that's far more expensive to fix than the original problem.
As a former Home Inspector with 15 years of experience, I've seen the aftermath of DIY gone wrong. Here are 10 jobs you should leave to a professional.
1. Electrical Work (Anything Beyond Bulb Changes)
Replacing a light switch yourself might seem harmless, but wiring errors cause house fires. In Ontario, most electrical work beyond very minor tasks legally requires a licensed electrician and an ESA inspection.
2. Gas Line Repairs or Connections
Natural gas leaks kill people. Gas line work requires a licensed gas technician in Ontario — it's not optional and not something any handyman should touch either. Call your gas provider or a licensed HVAC professional.
3. Load-Bearing Wall Removal
Removing the wrong wall can compromise structural integrity. Identifying load-bearing walls requires experience or an engineer's assessment. Getting it wrong means a collapsing structure, not just a visual problem.
4. Roof Repairs (Anything Beyond Cleaning)
Fall risk alone makes roofing dangerous without proper equipment. Beyond safety, improper flashing, shingle installation, or sealant application leads to leaks, rot, and mold — often months later when the source is hard to trace.
5. Foundation Cracks
A hairline crack might be cosmetic; a horizontal crack in a basement wall could indicate structural movement. Diagnosing foundation issues correctly requires trained eyes. Patching a serious crack yourself can hide a serious problem while it gets worse.
6. Asbestos and Lead Paint Disturbance
Homes built before 1990 may contain asbestos in insulation, floor tiles, or drywall compound, and lead-based paint. Disturbing these materials releases hazardous fibres or dust. Removal requires certified professionals with proper containment and disposal.
7. Drain Line Repairs
Clearing a slow drain with a plunger is fine. But cutting into drain lines, rerouting pipes, or addressing deep blockages without proper tools leads to leaks inside walls or under slabs — and those repairs are far more costly.
8. HVAC Installation or Repair
Improperly installed or repaired HVAC systems are inefficient at best and dangerous at worst. Carbon monoxide risks from gas furnace issues are real. Leave furnace, heat pump, and central AC work to certified technicians.
9. Drywall Near Plumbing or Electrical
Cutting into walls without knowing what's behind them risks hitting pipes, electrical wires, or both. A proper pre-investigation (even a stud finder and wire detector) is essential — and knowing what you're looking at when you find something takes experience.
10. Deck Structural Repairs (Footings, Ledger Board)
Replacing a few deck boards is manageable DIY territory. Replacing footings, reattaching the ledger board, or addressing major structural components is not. A deck that fails under load is a serious injury risk.
When in doubt, the safest move is a professional assessment. A consultation call costs nothing — call (289) 928-5689 to discuss your project.
Pedro Giorgana
Owner, Handy Man And Home Repairs — 16 years in construction, 15 years as a Home Inspector. Serving Durham Region, Kawartha Lakes & Northumberland.