To prepare for a plumbing renovation in your kitchen or bathroom, start with the decisions that determine the connections: which fixtures will stay, which will move, the finished dimensions and access to the existing pipes. Resolving these questions before ordering cabinetry or starting demolition gives everyone a more reliable basis for the work.
This guide helps you assemble a useful project file, separate municipal approvals from Québec licensing requirements and coordinate the work while your home remains occupied. You do not need to design the piping yourself. Your most useful contribution is to describe the result you want, make the constraints visible and have the technical questions checked before committing to expensive purchases.
Start with one decision: are you replacing fixtures in their current locations, moving them or adding more? These projects can require different access, checks and sequences of work.
Prepare for a plumbing renovation by defining the result
Write down the problems you want to solve. Is the vanity short of storage? Is the bathtub difficult to use? Would a deeper kitchen sink or a second basin make daily life easier? A list of needs lets you compare layouts without deciding too early where every fixture must go. Separate essentials from preferences you could change if the existing plumbing creates a constraint.
Next, describe what will remain. Keeping a toilet in place can simplify some work, but it does not establish the condition of the connection or confirm that the new model will fit. Even a wall-mounted vanity on the same wall can need a different arrangement of supply and drain outlets. An unchanged location does not automatically mean unchanged plumbing.
Prepare two sketches: the current room and your preferred layout. Mark doors, windows, fixtures and walls you may want to alter. Include measurements you have actually taken and label any estimates. A clear, dated sketch is more useful than an apparently exact drawing whose assumptions nobody understands.
If you are only changing a fixture without rearranging the room, see the plumbing fixture installation and repair service. A project involving several stages of alterations belongs with renovation plumbing. This distinction helps you describe the work accurately when requesting an assessment.
Document the existing room without taking it apart
Take a general photograph, followed by pictures of connections already visible inside cabinets. Photograph labels and collect useful invoices. Record the known age of the fixtures, previous repairs and symptoms you have noticed, such as odours, slow drainage, moisture marks or a shutoff that does not close properly. Keep observations separate from guesses about their cause.
Identify existing access through a basement, open ceiling, access panel or mechanical room. Explain whether the space below the bathroom belongs to another dwelling. You can point out a pipe without claiming to know its material or purpose. The professional will assess the water supply, drainage and venting systems in their actual setting.
Avoid opening walls or disconnecting equipment simply to improve the photographs. An opening can encounter wiring, pipes or hazardous materials. Do not force an old valve to find out whether it works. Instead, put the required checks on the list for the preliminary visit and let the contractor explain how access will be established.
Do not let a renovation conceal an active problem. If a leak develops, pause the planning and follow the safe first steps for a water leak. Tell the contractor about any drain chemicals already used and recent work on the connections before anything is handled.
Separate permits, licensing and technical compliance
A permit concerns municipal authorization for the project. A licence concerns the right to carry out or arrange certain work. Technical compliance concerns the installation requirements. The absence of one particular permit does not remove the other obligations, and a contractor’s licence does not authorize an otherwise unapproved alteration to the building.
Montréal’s interior renovation guidance states that the city no longer issues separate plumbing permits. The same guidance distinguishes minor replacements from alterations affecting matters such as walls, foundations or room divisions. Select the correct borough and describe the whole project. Asking only whether a faucet needs a permit can leave the important part of your renovation unanswered.
In LaSalle, consult the permit counter about the project and check the current contact arrangements. Ask which documents and authorizations apply. Where a permit is required, make its issuance a prerequisite for the affected work rather than assuming that submitting an application allows construction to start.
For a contractor you hire, verify the appropriate licence, including plumbing subclass 15.5, in the official register. The RBQ explains plumbing licensing. Exceptions for an owner doing their own work depend on the building and its use; consult the RBQ’s owner-performed work guidance. Do not apply an exception for an owner-occupied single-family home to a condominium or rental building without checking.
Check a proposed move before ordering custom pieces
A fixture needs a water supply, drainage and an appropriate connection to the venting system. Empty space on a floor plan does not prove that all these functions can be accommodated. Ask which parts of the proposed route have been verified and which remain concealed. A clear answer can change the layout while changes are still inexpensive.
For a relocated toilet, the main constraint may be below the floor. An island sink needs drainage and venting considered alongside the cabinetry. With a shower, the drain, base, surface thicknesses and access can affect one another. Have the overall approach checked before buying a custom component that depends on one exact location.
When both would meet your needs, ask about an option that keeps the existing locations and an option that moves them. Compare openings, restoration work and unresolved conditions as well as the plumbing price. Moving a fixture can improve the room; the useful question is what the decision means for the complete project.
Do not ask a plumber to route through a structural element on the strength of a sketch alone. If the route affects a beam, joist, slab or separation between dwellings, establish who is responsible for assessing and authorizing that work. A photograph cannot replace a required design or permission to drill.
Prepare a product sheet for every fixture
Collect the manufacturer, exact model number and installation instructions for each proposed fixture. A link to an entire product collection or an inspiration photograph is not enough. Two nearly identical versions can have different dimensions or accessories. Also confirm who will order the parts and who will check the proposed combination before it is purchased.
The RBQ requires plumbing products to be certified or approved for their intended use by a recognized organization. Before buying, have the applicable certification for that exact model checked. A seller’s claim of international quality is not a substitute for the required approval.
Your product schedule should identify included connections, parts sold separately, delivery dates and return conditions. For a concealed faucet, establish that the rough-in valve and the selected trim are the combination intended by the manufacturer. Attractive handles are not a substitute for the valve body that needs to be installed inside the wall.
Keep a dated version of the product schedule. If a model changes, send its new installation sheet to everyone affected before piping is prepared. Avoid last-minute substitutions based only on appearance. They can alter countertop drilling, wall depth or required clearances, even when the replacement looks almost identical in the showroom.
Kitchen plumbing: check the space below the countertop
A deeper sink leaves less space below the bowl. Drawers occupy a different volume from a cabinet with doors. Have the cabinet plan, sink, faucet and plumbing connections reviewed together. Put cabinet dimensions and drain locations on the same drawing so that each trade works from the same information.
Check where the spout directs water, the space behind the faucet and whether the handle can move fully near a backsplash. Identify the countertop holes needed for accessories such as a dispenser or drinking-water faucet. The countertop fabricator should receive confirmed selections before cutting. A hole that suits one accessory may not suit another.
Provide exact models for the dishwasher and any refrigerator connected to water. Ask about connection requirements, accessible water shutoffs and electrical responsibilities. Plan for an appliance to be removed for servicing without destroying permanent finishes. Cabinet installers should know about the intended routes before fastening or closing the surrounding units.
Plan everyday use during the disruption as well. Where will dishes be washed, which water point remains available and when will the sink actually be usable? Cabinet delivery, countertop installation and final plumbing connections are separate milestones. Booking the final visit before those conditions are confirmed can lead to a trip that cannot accomplish its purpose.
Bathroom plumbing: work from finished dimensions
For a toilet, have the connection distance, flange condition and finished floor height checked. For a vanity, compare drawer depth with the space needed for the trap and valves. A double basin introduces constraints that cabinet width alone cannot establish. Keep product drawings available while the arrangement is assessed.
For a bathtub or shower, gather the base, drain and faucet instructions. Confirm dimensions relative to the completed surfaces and their actual thicknesses. A mark measured from bare framing can become inaccurate once backer boards and tile are installed. Changing a finish build-up after rough-in should therefore be discussed before anyone proceeds.
Establish who installs the shower waterproofing and who checks the interfaces around drains and penetrations. Plumbing, membranes, wall finishes and sealants require coordinated responsibilities. Planned checks and product curing times come before use. The date of the last plumbing connection alone does not determine when the shower is ready.
Discuss future use: reaching the controls, cleaning, children’s needs or access for someone with reduced mobility. Ask about suitable temperature-control protection. These choices may affect faucet position or call for structural and finish coordination before walls are closed. Raising an accessibility concern early leaves more room to find a practical arrangement.
Plan openings and assess suspect materials first
Fresh paint does not prove that the materials underneath are recent. Before cutting or demolition, share the building’s known age and any available assessment reports. Health Canada advises professional assessment of suspected asbestos materials and avoiding disturbance yourself; see its renovation safety guidance.
The CNESST guidance on identifying suspect asbestos materials addresses checks before work that may release their dust. Establish who reviews the information, arranges any necessary testing and adjusts the schedule to the results. A small opening does not automatically rule out the issue.
Agree on what happens if an opening reveals moisture, deterioration or an unexpected material. Identify who pauses the work, documents the finding, proposes the next step and authorizes its cost. Settling that process in advance avoids hurried decisions after the bathroom has already become unusable and other trades are waiting.
Plan the debris route and protection of the rest of the home. Leave containment and treatment methods to competent people according to the identified risk. An ordinary mask, an open window or a thin dust sheet is not a universal solution for renovation dust. Explain the work area arrangements to occupants before the space is disrupted.
Coordinate a condo or occupied dwelling
Before scheduling a shutdown, identify the person authorized to coordinate it. A valve may serve one unit or several dwellings. Ask the manager or condominium syndicate how shared-system work, mechanical-room access and entry into another unit are approved. The person letting a contractor into your unit may not have authority over the common piping.
Check building rules for noise hours, elevator reservations, corridor protection, parking and debris removal. Have the responsible person confirm any documentation requirements. Municipal authorization does not replace the arrangements needed to access common areas. Write down who will provide keys or meet the contractor, especially when access depends on more than one household.
In a rented dwelling, coordinate with the owner and occupants according to the applicable obligations. Identify rooms that will be unavailable and needs that should be anticipated. Avoid promising an interruption lasting only a few minutes before the professional has assessed the work and the means of isolating the system.
Prepare a practical notice stating the expected window, affected services and a reachable contact. Allow for unexpected conditions and agree on how changes will be communicated. If the dwelling has only one toilet, decide on an acceptable temporary arrangement before disconnection. The household’s ability to remain there is part of planning, not an afterthought.
Compare quotations for the same scope
Give contractors the same file: sketches, models, photographs, access details and proposed stages. Ask them to separate confirmed items from assumptions and exclusions. A price without a defined scope does not tell you whether two quotations cover the same result. Ask questions about differences before treating one as a saving.
The Office de la protection du consommateur recommends a detailed written contract covering matters such as work, materials, dates, price and payments. The RBQ recommends checking the licence when signing and specifying who obtains any required permit.
For your project, distinguish disconnection, rough-in piping, supplies, final connections and checks. Identify openings, electrical work, structural work, waterproofing and finishes separately. State who supplies the fixtures and how a missing part or unsuitable customer-supplied product will be handled. This helps prevent a plumbing quotation from being mistaken for a complete room renovation.
Agree in writing on a change process: describe the change, identify its price and schedule effects, then obtain authorization before proceeding. A contingency in your budget does not automatically authorize every extra. Avoid universal prices per fixture when pipe condition, access and restoration remain unknown. Those conditions can matter more than the number of visible fixtures.
Set hold points in the renovation schedule
Organize work around verifiable conditions. Openings follow the relevant authorizations, risk assessment and shutdown arrangements. Rough-in requires confirmed product choices and dimensions. Final connection depends on installed equipment, ready surfaces and available parts. Assign someone to confirm each condition so that the next trade does not arrive on an assumption.
Most importantly, plan a hold point before pipes are concealed. The professional needs access for appropriate tests and any applicable inspections. Establish who arranges these checks and who then authorizes closure. Photographs are useful records, but they do not by themselves demonstrate a successful test or replace a required inspection.
The RBQ explains Québec’s Plumbing chapter, which incorporates the National Plumbing Code 2020 with Québec amendments. Have the requirements for the actual work confirmed. An older installation is not automatically a model for how new work should be carried out.
Keep one shared schedule showing outstanding decisions. A tiler’s reserved date is not a reason to close a wall while a necessary check remains incomplete. Delaying a finish can be inconvenient; reopening a new surface after concealing a problem is often more disruptive. Discuss the decision while access is still available.
Plan recommissioning and keep a final project file
Before using the new installation, ask for a demonstration of the affected fixtures and the location of their water shutoffs. Record completed checks and items still awaiting completion. If service is restored only partially, occupants need a clear explanation of which fixtures can be used and which must wait.
Store invoices, model numbers, instructions, warranties and photographs of work before concealment in a file organized by room. Include the authorizations and documents received. Keep the contact for reporting a problem and the agreed process for adjustments after completion. Future servicing is easier when an unfamiliar cartridge or concealed valve can be identified without guesswork.
At handover, review accessible areas with the contractor. Point out a drawer hitting a connection, an inaccessible shutoff or unfinished work. Record concerns precisely and keep the agreed response. A working basin is a useful check, but it is not a complete inspection of every plumbing system in the building.
You can use this file to discuss your project with Plomberie LaSalle: address, room, fixtures staying or moving, photographs and preferred timing. Availability and scope are confirmed for your circumstances. For related reading, browse plumbing tips or the Repairs and installations category.
Frequently asked questions before renovating
Should I buy all the fixtures before the first visit?
Select proposed models and collect their instructions, then have compatibility checked before a purchase that is difficult to return. Some components are needed during rough-in; others are used at final connection. Ask which parts must be available at each stage and who confirms that the deliveries are complete.
Does keeping the same fixture locations guarantee simple work?
No. Sink depth, vanity drawers and finished floor height can change the connection requirements. Existing pipe condition also needs assessment. Keeping the layout removes some uncertainties without removing them all. Tell the contractor about new cabinetry or surface changes even if the fixtures stay against the same wall.
Can work start immediately if there is no plumbing permit?
Not necessarily. The full project may require a renovation permit, condominium permissions or coordinated access. Confirm the process for the exact address and scope, along with provincial requirements and responsibilities, before starting the affected work. Do not treat advice for a minor fixture replacement as authorization for a broader conversion.
Can photographs establish a firm completion date?
Photographs help prepare a discussion but do not reveal the full pipe route or concealed conditions. Ask for a schedule showing assumptions, preliminary checks and dependencies on other trades. An estimated duration is also different from a confirmed appointment. Product delivery and site readiness must fit the proposed sequence.
What document best prevents misunderstandings?
A shared, dated project file containing the two layouts, exact product schedule, responsibilities and unresolved decisions is a strong starting point. Add the written scope and change-authorization process. Send significant changes to everyone affected before they complete their stage, rather than relying on a conversation that only one person heard.
Sources and verification notes
The official links within this guide were consulted on November 4, 2026: Ville de Montréal and the LaSalle permit counter for municipal procedures; the RBQ for licensing, exceptions, products and the Code; CNESST and Health Canada for planning openings; and the Office de la protection du consommateur for contracts. These preparation lists are practical planning suggestions. Responsible authorities and professionals confirm the requirements for your actual project. Some municipal and CNESST resources linked here are in French.