A structural plan establishes the path the loads take down to the ground and checks that every element along that path can carry them. It's required for the permit as soon as a load-bearing element is altered. The time needed to produce the plans depends on the scope and is stated in the service proposal.
Most people think a structural plan is for getting a permit. That's true, but it's the smallest part of what it's for. A good plan is mainly there so the contractor doesn't have to improvise on site.
On site, the same scene often plays out: a project well drawn by the architect, a tight budget, and a beam whose load path down to the foundation nobody checked. Fixing it usually costs more than the study someone tried to avoid.
What a structural plan really contains
A structural plan isn't an architect's drawing with beams added. It's a technical document that answers a specific question: what path do the loads take down to the ground, and can every element along that path carry them?
A complete set includes the framing for each level, the foundations, connection details at critical points, general notes that specify materials and their strengths, and the table of design loads. That last item is what separates a plan you can check from a decorative one.
The seal isn't a courtesy signature
When an engineer applies their seal, they take professional responsibility for the calculations, the load assumptions and the buildability of what they've drawn. They can't seal plans they haven't designed or checked themselves.
The code changes in October 2026, and it affects you
The Building chapter of the Quebec Construction Code incorporating the National Building Code 2020 came into force on April 17, 2025. An eighteen-month transition period still allows design to the previous edition.
That period ends on October 17, 2026. Construction or alteration work that starts on or after that date must comply with the new edition. For a project whose plans are being prepared now and whose construction will start in the fall, the question isn't theoretical: it changes the applicable requirements.
In practical terms, design has to target the new edition starting today for any project whose permit and start of work will fall after that date. It's a point to confirm before starting the calculations.
The four families of projects, and what they require
Not every design assignment takes the same effort. Here's how we classify them when a client calls us, and what each one really involves.
- Simple scopeOpening in a load-bearing wallOne beam, two supports, a load path to check down to the foundation. The work is straightforward when the existing structure is accessible and documented.
- Moderate scopeAdding a storey or an extensionThe question isn't drawing the new storey; it's proving the existing structure can carry it. That means tracing the loads down to the foundations and often checking them with test pits.
- Moderate scopeNew residential buildingA house, plex or small apartment building. The work starts with the structural grid and ends with the connection details. That's where coordination with the architect saves the most time.
- Complex scopeCommercial, industrial, long spanLong spans, concentrated loads, bracing. Sizing becomes an optimization exercise where every kilogram of steel saved shows up in the budget.
Complexity isn't measured by floor area. A small opening in a load-bearing brick wall of a Plateau triplex sometimes calls for more checks than a new garage in the suburbs.
How an assignment unfolds, from the first call to the seal
The process is short when the information is available from the start. Here's the real sequence.
- Scoping by phone: nature of the project, age of the building, existing plans, constraints from the architect or contractor.
- Technical visit, usually a day or less. We record the actual dimensions, locate the load-bearing elements and open up if needed to see what's hidden behind the finishes.
- Analysis and calculations: load takedown, sizing, checking the existing supports and foundations.
- Production of the set of plans, with the general notes, connection details and load table.
- Signed and sealed issue, then follow-up with the contractor during construction for the questions that come up on site.
The fifth step isn't optional. A plan with no one to talk to during construction often ends up being interpreted, and interpreting a structural plan is the job of whoever sealed it.
Steel, engineered wood or concrete: how we decide
The choice of material is rarely about looks. It comes down to the span, the depth available in the ceiling, site access and supply lead time.
| Where it wins | Its limits | What it demands on site | |
|---|---|---|---|
| Steel | Long spans with a reduced beam depth | Fabrication lead time and corrosion protection | Access for handling, and installation at exactly the right level the first time |
| Engineered wood | Typical residential work, built-up beams that are easy to handle | Sensitivity to moisture, shorter spans for the same depth | Dry storage and properly sized supports |
| Concrete | Foundations, slabs, underpinning | Curing times and significant dead weight | Careful formwork and quality control of the concrete delivered |
In Montreal renovations, access is often the deciding factor. A steel beam that's ideal on paper is useless if it won't fit through the basement door or if the crane can't set up in the back lane.
The question to ask early
Before settling on a material, ask how the piece will get into the building. That one question heads off many unpleasant surprises on renovation sites.
What derails a project
Delays rarely come from the calculations. They come from missing information and decisions made in the wrong order.
- Calling the engineer after the architect. Once the geometry is fixed, all that's left is to make it possible, sometimes at the cost of a column in the middle of the living room.
- Not finding the original plans. Without documentation, everything has to be measured on site, and some checks require opening sections of ceiling.
- Underestimating the foundation. A new load has to go down somewhere. If the existing footing isn't enough, the project changes in nature.
- Changing the concept after the plans are issued. Every change in span or support triggers a new check, and there's no informal version of a sealed plan.
A plan that can't be built isn't a plan. It's a drawing.
What the city checks in your plans
Montreal's boroughs don't review the calculations. They check that the documents exist, that they're signed and sealed by an authorized professional, and that they match the project described in the permit application.
Consistency is what most often holds things up: architectural plans showing a seven-foot opening and structural plans sized for six, an address that doesn't match, an undated revision. These are details, and they cost weeks.
A sealed plan doesn't authorize the work on its own
The seal certifies the design. The permit authorizes the work. Starting before the permit is issued exposes you to a stop-work order and, for a load-bearing wall, an obligation to restore the original condition.
Timelines to expect
Here's what to expect when the file is complete.
- The technical visit: usually a day or less. The date is set with you, based on availability.
- The plans: a timeline stated in the service proposal. An opening in a load-bearing wall takes less time than a new building.
- Permit processing: varies by borough. This step isn't in our hands, but a consistent file can shorten it.
What stretches a schedule is often waiting for information: a land surveyor's survey, a soil report, a client decision on the finished ceiling height. The calculations take the time they take, and they're rarely the critical path.
FAQ
Do I really need an engineer, or can the contractor decide?
As soon as a load-bearing element is altered, added or removed, the municipality requires plans signed and sealed by an engineer before it issues the permit. An experienced contractor often knows how to install a beam properly, but can neither size it nor seal the plans. Professional responsibility can't be delegated.
Does my project have to comply with the new edition of the Construction Code?
Work that starts on or after October 17, 2026 must comply with the Building chapter incorporating the National Building Code of Canada 2020, as amended for Quebec. For projects that start before that date, the transition period still allows the previous edition to be applied. What counts is the date work starts, not the date of design.
Do you need a soil report for an addition?
Not always, but often. As soon as significant loads are added or new foundations are set at a different depth from the existing ones, knowing the soil's bearing capacity becomes necessary. In the clay areas of the Montreal region, a geotechnical study avoids designing a foundation on an optimistic assumption.
Can you work from my architect's plans?
Yes, and it's the most common situation. Ideally, we come into the project while the geometry can still be adjusted: a column grid moved a few feet at the right time often simplifies the entire structure. We then remain available for the contractor's questions during construction.
What happens if the contractor wants to change something during construction?
They call us before they cut. A change in beam type, support location or fastening method may be acceptable, but it has to be checked and documented. A change made on site without approval makes the sealed plan inapplicable and complicates acceptance of the work.
A project to have drawn up?
We design structural plans for residential and commercial projects and for extensions in Montreal, on the South Shore, on the North Shore and elsewhere in Quebec. The timeline for the plans is stated in our written service proposal, based on the scope.
Discuss Your ProjectNote: The requirements described reflect the Quebec regulations in force at the time of the update. Permit requirements vary from one borough to another.
Sources: Régie du bâtiment du Québec, Building chapter of the Quebec Construction Code including the NBC 2020 as amended for Quebec, in force April 17, 2025, mandatory for work starting on or after October 17, 2026. Engineers Act (CQLR, c. I-9).