How to Budget a Bathroom Renovation
Without Surprises

The first thing every Ottawa homeowner asks me about a bathroom renovation is "how much?" Bathrooms cost more than people expect. Per square foot, they're the most expensive room in the house.

The reason is plumbing, waterproofing, electrical, tile labour, and the fact that almost everything in a bathroom is custom-cut to fit. A 6 by 9 foot bathroom can easily cost more than a 12 by 14 foot bedroom renovation, and people are genuinely shocked by that the first time.

Here's how bathroom pricing is actually built on Ottawa projects, what drives the number for each tier, and the hidden conditions that turn a tidy quote into a bigger invoice if you don't plan for them. The goal is a detailed written breakdown, line by line, before you sign anything.

The Three Real Tiers in Ottawa

Bathroom scopes cluster into three groups based on what's in the room and what gets touched. The tier you land in is set by inclusions, not a sticker price:

Powder room (Essential scope)

A 2-piece (toilet, sink). Usually 4 by 5 feet. No shower or tub. The most affordable bathroom to renovate because there's no waterproofing, no shower glass, no tub plumbing. A typical Ottawa powder room scope is a full gut with new tile floor, new vanity, new toilet, new lighting, fresh paint, and a small adjustment to the layout (move the toilet, swap pedestal for vanity, etc.).

Main bathroom (Mid scope)

The 3-piece (toilet, sink, tub or shower) or 4-piece (toilet, sink, tub, separate shower) most Ottawa families use as the kid bathroom. 5 by 8 to 6 by 10 feet. This is the workhorse renovation: a full gut with tile shower, new tub, double or large single vanity, mid-range fixtures, porcelain tile floor, and a fan upgrade. Switching a tub-only setup to a separate shower adds drain and waterproofing scope, which moves the number up.

Primary ensuite (Premium scope)

5-piece (toilet, double sink, freestanding tub, separate large shower) or spa-style with extras like steam, heated floor, custom storage. Typically 8 by 12 feet or larger in newer Kanata, Barrhaven, or Findlay Creek builds. The projects at the top of this range usually carry heavy stone work, custom millwork, or both.

Where the Money Actually Goes

For a typical Ottawa main bathroom, the cost drivers break down like this. A transparent proposal itemizes each one so you can see exactly what shapes the total:

• Demo and disposal: 1-2 days, dumpster, hauling.
• Plumbing rough-in and fixtures: rough valves, drains, supply, plus toilet, faucets, shower trim.
• Electrical rough-in and fixtures: GFCI, fan, vanity light, pot lights, ESA permit.
• Waterproofing membrane: Schluter Kerdi or equivalent, non-negotiable.
• Tile and tile labour: usually the largest single driver; labour scales with the amount and complexity of the tile work.
• Vanity, top, mirror: driven by size and material allowance.
• Shower glass enclosure: custom-fit, tempered.
• Drywall, paint, trim.
• Project management, permits, contingency.

Tile labour surprises people the most. A 5 by 5 shower wall is 25 square feet; three walls plus the curb and the niche is around 80 square feet. Every cut, the floor, and the niche shelf adds labour, and that's before the tile material itself. This is why a detailed written breakdown matters more than a single lump-sum number.

Waterproofing: The Layer You Cannot Skip

If a contractor in Ottawa quotes you a tile shower without a sheet-applied or liquid-applied waterproofing membrane (Schluter Kerdi, Wedi, Laticrete Hydro Ban, or equivalent), walk away. Cement board with thinset is not waterproof. It's water-resistant, which means your shower will leak in 5-8 years and you'll be redoing it.

Proper waterproofing is a modest line item in materials and labour for a typical shower. It's the single most important thing in the whole bathroom. If the quote doesn't mention the membrane brand by name, ask.

The only thing more expensive than waterproofing your shower is not waterproofing your shower. The first one's a line item. The second one's a mould remediation a few years down the road.

Plumbing: The Cost of Moving Things

If your new bathroom layout is the same as the old one (toilet here, sink there, tub here), plumbing is straightforward. The minute you start moving fixtures, the scope grows:

• Move the sink to a new wall: added supply and drain rework.
• Move the toilet to a new location: the drain is in the floor, so moving it means opening the ceiling below — a real jump in scope.
• Convert tub to walk-in shower with linear drain: different drain location, sloped subfloor.
• Add a second sink to a single-vanity layout: added supply, drain, and vanity work.

This is why your designer asks "do you really need to move the toilet?" early in the conversation. The answer is sometimes yes, sometimes no, but the scope difference is real and it belongs in the written proposal.

Hidden Costs That Catch People

These almost never show up in the original quote, but they're in 30% of Ottawa bathroom renovations once demo opens the walls:

1. Subfloor rot under the toilet or tub. Common in homes built before 1990 where wax rings have leaked for years. The repair scope depends on the extent of the rot.
2. Galvanized supply lines. Pre-1980 houses sometimes have galvanized steel water lines that are corroded to half their original diameter. Replacing them while the wall is open adds plumbing scope.
3. Lead solder on copper joints. Pre-1986 plumbing. Code now requires lead-free solder. If a soldered joint needs to be cut and redone, the lead joint becomes a small remediation issue.
4. Inadequate venting. Old bathrooms often have a fan that vents into the attic instead of outside. Code requires vented to exterior, and re-routing the duct adds labour.
5. Knob-and-tube electrical. Houses in the Glebe, Hintonburg, Westboro, and Centretown built before 1950 often still have it. Insurance won't cover it, and replacing the bathroom branch adds electrical scope.
6. No vapour barrier behind tile. 1970s-80s bathrooms often have green board with no vapour management. Once it's open, it has to be done right.

The Contingency Rule (10% Minimum, 15% Smarter)

Set aside 10-15% of your bathroom budget as contingency before you sign anything. It's the money you keep in reserve instead of spending on tile.

If you don't hit a surprise, congratulations, you have a reserve you didn't expect to keep. If you do, you're not having the conversation where the project stops at week 3 because you're out of money.

Set the contingency aside in cash or available credit, not "we'll figure it out." The phrase "we'll figure it out" is where renovations go to die.

Where to Save and Where Not To

Value engineering is about where your material allowance goes, not cutting corners. Things you can keep modest without regret:

• Toilet (a budget toilet works as well as a premium one for most households)
• Vanity (a value-line cabinet looks great with a stone top)
• Mirror (any size, hardware store)
• Floor tile (mid-range porcelain looks fine; nobody studies your floor)
• Paint (this is paint)

Things you should not cut back on:

• Waterproofing membrane (already covered)
• Shower valve (Moen, Kohler, Delta cartridge brands have parts available 20 years from now; off-brand doesn't)
• Tile labour (a budget setter and a skilled setter make the same shower look completely different)
• Exhaust fan (a quality unit like Panasonic WhisperGreen lasts 20 years; a builder-grade fan is dead in 5)
• Shower glass (1/2" tempered, custom-fit, with a real seal)

Timeline (And Why It Affects Cost)

A typical Ottawa main bathroom is 4 to 6 weeks on site. An ensuite is 6 to 9 weeks. Powder room is 2 to 3 weeks. Add 6-10 weeks before for design, fixture selection, and any custom orders.

The schedule affects cost because trades come in waves: demo day, then plumber, then electrician, then waterproofing, then tile, then plumber back for trim, then electrician back for fixtures, then glass installer. Each trade visit has a minimum charge. A bathroom is 8-12 trade visits, which is why "small" bathrooms aren't cheap.

If you want a properly-scoped fixed-price bathroom renovation in Ottawa with the line items spelled out and the contingency planned for, that's exactly what we put on paper before we ask you to sign anything. The goal is no surprises by week 4.