Full bathroom renovation

A full bathroom renovation is the densest trade work in a house. Demolition, framing, plumbing, electrical, ventilation, waterproofing, tiling, drywall, painting and finishing all happen inside a room of four or five square metres, and each trade has to wait for the one before. That is why a small room takes weeks and why the schedule, not the tile, is what you are really buying.

Step one: decide whether the layout moves. This decision changes the permit, the cost and the timeline more than any finish choice. The City requires a permit for alterations, additions or extensions to a plumbing system, with replacing existing fixtures as the exception, and separately for adding or removing walls (City of Ottawa, Do I need a building permit). Swapping fixtures in place avoids it. Moving the toilet 600 millimetres does not.

Step two: demolition and discovery. Everything out to the studs and the subfloor, and this is where the budget holds or does not. Common finds: rotten subfloor at the toilet flange, a shower pan that has been quietly wetting a joist, galvanised supply piping, a cast iron stack, no vapour barrier on an exterior wall. Insist on a written contingency allowance of ten to fifteen per cent.

Step three: rough-in. Plumbing first, then electrical, then ventilation ducting. The plumbing has to be done by someone certified, because plumber is a compulsory trade in Ontario. Electrical work must be reported to the Electrical Safety Authority before it starts, and hired electrical work must be done by a Licensed Electrical Contractor (Electrical Safety Authority, Notifications and inspections). The fan gets ducted outside in insulated duct, not into the attic. Then the inspections, before anything is closed up.

Step four: waterproofing, and then tile. The Ontario Building Code requires that ceramic and plastic tile installed on walls around bathtubs or showers be applied over moisture resistant backing (OBC 9.29.10.4, Moisture Resistant Backing), and that the joints between wall tiles and a bathtub or shower be suitably caulked with a material conforming to CAN/CGSB-19.22-M, the standard for mildew resistant sealing compound for tubs and tile (OBC 9.29.10.5, Joints between Tiles and Bathtub). Current practice in a custom shower goes further than the Code floor: a sheet or liquid-applied waterproofing membrane over the backer board, a sloped mortar bed or a pre-formed pan, and a flood test before a single tile goes on. Ask for the flood test.

Step five: finishing. Drywall, taping, primer, paint, then the vanity, toilet, fittings, glass and trim. Shower glass is measured only after the tile is in, which adds one to three weeks of lead time at the very end.

How long it takes. A standard Ottawa bathroom of about 4.5 square metres (50 square feet), gutted and rebuilt with the layout unchanged, is three to four weeks of working time. Moving plumbing adds a week or more plus the inspection schedule. Long lead-time items stretch the calendar without adding working days, which is worth separating in the contract.

What it costs in Ottawa in 2026. Indicative ranges rather than quotes. A standard main bathroom gutted and rebuilt with mid-range finishes and no layout change commonly runs $18,000 to $30,000. The same room with the plumbing relocated, a custom tiled shower and better finishes is usually $30,000 to $55,000. A powder room is $8,000 to $15,000. What moves the number: whether plumbing moves, whether the subfloor or joists need repair, tub or tiled shower, the tile format, whether the vanity is stock or custom, and whether a structural change needs an engineer.

What makes an Ottawa bathroom different. Ventilation, because of the humidity swing. A house here runs very dry indoors in January, which means a bathroom with inadequate exhaust dumps its moisture into cold wall and attic cavities where it condenses. The Code's Part 9 ventilation provisions set principal exhaust capacity by bedroom count, from 15 litres per second for a one-bedroom dwelling to 45 for five (OBC 9.32.3.4, Principal Exhaust), with supplemental exhaust required so that the total capacity of kitchen, bathroom and water closet exhaust reaches the required total ventilation capacity minus the principal fan (OBC 9.32.3.5, Supplemental Exhaust). In practical terms, an old 30-year-old builder fan ducted into the attic is one of the most common defects found during an Ottawa bathroom demolition, and fixing it properly is not expensive. The second local factor is housing stock: the 1950s and 1960s bungalows across Alta Vista, Elmvale and older Nepean have cast iron stacks, galvanised supply and 1.5 metre steel tubs set into mortar, and none of those come out cleanly.

Which credentials are required. Plumber is a compulsory trade in Ontario, trade code 306A, and to practise it legally a person must hold a Registered Training Agreement, a Provisional Certificate of Qualification or a Certificate of Qualification, which must be renewed to stay valid and which you can check on the Skilled Trades Ontario public register (Skilled Trades Ontario, Plumber, trade code 306A). Electrical work for hire must be done by a Licensed Electrical Contractor (Electrical Safety Authority, Notifications and inspections). General contracting and tiling are not licensed trades in Ontario, so for those the things you can verify are liability insurance and WSIB coverage, which since 5 December 2024 is compulsory for most independent operators and sole proprietors in construction, with a narrow exemption for work on an existing private residence contracted directly by the occupant (WSIB, Expanded Compulsory Coverage in Construction).

What to ask before you hire. Is a permit required, and who applies. Who does the plumbing, and what is their 306A number. Who does the electrical. Where does the fan duct discharge. Which waterproofing system, and will you flood test the pan. What is the contingency allowance and how is it drawn down. What is warranted, and for how long.