Renovation Drawings in Ontario: Who Prepares Them

Most renovations that need a building permit also need drawings good enough for the building department to review and for a contractor to build from. Those are usually called permit drawings. They are not a sketch on the back of an envelope, and they are not the same as the glossy pictures in a renovation magazine. They show the existing house, the proposed work, the materials and the structure, at a scale a reviewer and a builder can read.

Who prepares them depends on the job. A BCIN designer, a licensed architect or a professional engineer can prepare drawings for a permit. An owner may prepare drawings for their own house. Structural work usually brings in an engineer. The earlier you settle who is drawing, the fewer surprises you meet at the permit counter.

What permit drawings actually contain

Permit drawings are a package, not a single sheet. For a typical renovation they include:

• Site plan showing the lot, the house footprint, setbacks and any proposed addition.
• Floor plans of the existing layout and the proposed layout, with room names and dimensions.
• Elevations showing exterior faces where the work changes them.
• Sections cutting through the construction to show how floors, walls and roofs go together.
• Structural drawings where walls are removed, beams added or openings enlarged.
• Notes and specifications naming materials and methods the Building Code requires.
• Mechanical and electrical layouts where new bathrooms, kitchens or heating equipment are part of the work.

Not every renovation needs every sheet. A bathroom renovation in the same footprint needs less than a two-storey addition. The building department will tell you what it expects for your application, and it is worth asking before the designer starts drawing.

Who is allowed to prepare the drawings

Ontario does not let just anyone produce drawings for a permit. The Building Code sets out who may prepare them:

A BCIN designer is registered with a Building Code Identification Number in a category that matches the project. A designer registered for houses may not be registered for larger buildings, and the building department will check. Ask for the BCIN and the category before signing a design contract.

An owner drawing their own house is allowed, but the drawings still have to meet the Building Code and zoning by-law, and the building department will review them like anyone else’s. Many owners find the review comments harder to answer without design experience.

Do you need an architect for a renovation?

Usually not. Most house renovations in Ontario are drawn by BCIN designers, and an architect is not required by the Building Code for a typical house project. An architect is worth considering where the design itself is the hard part: a major addition, a heritage house, a complicated layout, or a project where the owner wants one professional to carry the design from concept through construction review.

What matters legally is that the drawings come from someone permitted to prepare them. What matters practically is that the drawings are complete enough to build from and to quote from. A designer who knows the local building department and produces a full package is often more useful than a famous name with a thin set of sheets.

When a structural engineer is needed

Structural work is where drawings most often fall short. Removing a load-bearing wall, adding a beam, enlarging an opening in an exterior wall or adding a storey all change how loads travel through the house. Those changes need a design by a qualified designer or engineer, and a building permit.

A structural engineer is usually brought in when:

• a load-bearing wall is being removed or altered;
• a new beam or post is being added;
• an opening in an exterior or load-bearing wall is made new or larger;
• an addition carries new loads onto an existing structure;
• the building department asks for engineering on a specific detail.

The structural drawings show the beam size, the connections and the posts; an engineer’s drawings carry a stamp. The building department will not accept a contractor’s guess at a beam size. If the project is a kitchen opening, the sequence is set out in opening up a kitchen: removing a load-bearing wall.

Measured drawings of the existing house

Good permit drawings start with an accurate picture of what is already there. That means measured drawings: someone visits the house and measures the rooms, walls, openings, ceiling heights and the location of stairs, windows and services. Guessing from memory or from an old real estate listing produces drawings that do not match the house, and the building department or the contractor will find out on site.

Measured drawings matter most in older homes, where walls are out of square and previous renovations may not match any record. They also show whether a wall is load-bearing, which decides whether an engineer is needed. If the designer never visits, ask why.

How drawings feed the quotes and the contract

The drawings are the common language between the owner, the designer, the building department and the contractors bidding the work. A complete set lets several contractors price the same scope, which makes their quotes comparable. A vague set lets each contractor imagine a different job, and the quotes come back far apart for reasons that have nothing to do with price.

Before signing a renovation contract, the drawings should be attached to it or referenced in it, along with the specifications. Any change to the scope, price or schedule should be written and signed by both sides before the extra work is done. The province recommends written estimates from at least three contractors, and drawings are what make those estimates mean the same thing.

The order of decisions is usually: settle the scope, confirm whether a permit is needed, have the drawings prepared, apply for the permit, then tender the work to contractors. Skipping ahead to a contractor before the drawings exist usually means paying for revisions later. The step-by-step sequence is set out in how to plan a home renovation in Ontario, step by step, and the permit question is covered in do you need a building permit for a renovation in Ontario?.

What the building department reviews

The building department checks the drawings against the Building Code and against the zoning by-law. Zoning sets setbacks, height, lot coverage and use. If the drawings do not meet the by-law, the owner can apply to the municipality’s Committee of Adjustment for a minor variance, which adds time to the schedule.

Once a permit application is complete, the Building Code requires the municipality to issue or refuse a permit for a house within 10 business days. Incomplete applications do not start the clock, and many first submissions are returned for more information. That is why the quality of the drawings matters more than the speed of the designer.

The permit also names inspections at stages of the work, such as footings and foundation, framing, insulation and air barrier, plumbing and a final inspection. Covering work before it is inspected can mean opening it up again.

Other trades and their own permits

Drawings do not replace the permits that individual trades must take out. Paid electrical work in a renovation is done by a Licensed Electrical Contractor with an ESA permit from the Electrical Safety Authority, and the contractor files the permit. Gas work is done by a TSSA-registered contractor. Plumbing changes need a plumbing permit and a licensed plumber. If the drawings show new plumbing fixtures or moved drains, the plumbing permit is often a separate application from the building permit; the building department will say how it handles it.

Where a renovation touches a deck, a porch or a new addition, the drawings should show the guards and the footings, and utility locates through Ontario Dig Authority (formerly Ontario One Call) are required before any digging. For an addition, the design questions start earlier and are set out in planning a home addition in Ontario.

What goes wrong

Most permit delays trace back to the drawings, not to the building department.

• Drawings that do not match the house. A designer who never measured the existing rooms produces plans the reviewer or the contractor cannot reconcile with the site.
• Missing structural design. A load-bearing wall shown removed with no beam design and no engineer’s stamp sends the application back.
• Wrong designer category. A BCIN designer registered for the wrong type of work cannot sign off the drawings the building department needs.
• Incomplete applications. Missing sheets, missing site plan information or unanswered zoning questions stop the 10-business-day clock from starting.
• Drawings that are too vague to quote. Contractors price different jobs, and the owner cannot compare the quotes.
• Changes made on site without revised drawings. The work drifts from the permit, and the final inspection finds it.
• Skipping the trades’ own permits. Electrical work without an ESA permit, gas work without a TSSA-registered contractor, or plumbing changes without a plumbing permit and a licensed plumber can mean rework and delay.

A few habits prevent most of this. Ask for the designer’s BCIN and category in writing. Ask whether the fee includes responding to building department comments. Confirm in writing who is responsible for the structural design if a wall comes out. Keep the drawings and the contract together, and put every change in writing before the work is done. Where a contract term or a lien question matters to you, speak to a lawyer; where a local rule matters, ask your municipality’s building department.