Drawings and Field Conditions: Who Is Responsible When They Do Not Match?
Updated: Sep 20
Every commercial construction project reaches the same moment. A wall gets opened, a ceiling tile comes out, a slab gets scanned, and suddenly the drawings and field conditions do not agree. The documents say one thing. The building says another. Work stops, and somebody asks the wrong question first.
The wrong question is "who made the mistake?" The right question is "who carries this risk under our contract, and how quickly can we make a decision?" On a commercial project in Ontario, the distance between those two questions is usually measured in weeks of schedule and tens of thousands of dollars.
Here is how responsibility is actually assigned when drawings and field conditions conflict, and what you can put in place before a shovel goes in the ground to keep that conversation short.
Why drawings and field conditions stop agreeing
A conflict between drawings and field conditions is rarely a sign that somebody was careless. In an existing building it is close to inevitable. Four causes account for most of what I see on office, industrial and retail projects.
The as-built drawings were never as-built
Most sets labelled as-built are really the last issued-for-construction set with a few markups. Field changes made on a Friday afternoon twenty years ago never made it back to the drawing. The set is honest about design intent and silent about what was actually built.
The building has been renovated more times than anyone documented
Every tenant improvement leaves something behind: an abandoned duct, a filled-in opening, a slab patch, a circuit feeding a panel nobody can find. Each one is a small undocumented deviation, and they compound.
Design assumptions meet real structure
A designer working from a partial survey has to assume something about beam depths, slab thickness, existing capacity, or where the services actually run. Good assumptions are still assumptions, and the field is where they get tested.
Two consultants and drawings that were coordinated enough
Architectural, structural, mechanical and electrical drawings are coordinated to a standard, not to perfection. Clashes a model would have caught show up on site as a duct and a beam competing for the same 300 millimetres.
Who is responsible when drawings and field conditions conflict?
Responsibility follows the delivery model you chose, and it is settled long before the conflict appears. This is the most useful thing an owner can understand about project delivery.
Design-bid-build: the owner generally carries the design
When you hire a consultant to produce drawings and then tender those drawings to a contractor, you are the party who handed over the documents. Canadian courts have long recognised the principle that an owner who supplies plans and specifications gives an implied assurance they are adequate for the work. If the drawings and field conditions conflict because the design missed something, that is usually an owner cost, recoverable from the consultant only where the consultant fell below the professional standard of care. Your contractor is entitled to a change order.
Design-build: one party owns the answer
Under a design-build agreement such as CCDC 14, the design-builder is responsible for both the design and the construction. That single point of responsibility is the entire commercial logic of the model. When a drawing does not match the field, there is no gap between two firms to argue across. The design-builder verifies, redesigns and builds, and the price moves only if the owner changed the requirements or the condition genuinely could not have been anticipated.
What the contractor owes you under either model
No delivery model lets a contractor build something they knew was wrong. Standard Canadian construction contracts require the contractor to review the contract documents and to report errors, inconsistencies and omissions promptly, rather than proceed and invoice the consequences. A contractor who spots a conflict, says nothing, builds it, and then claims the rework is usually in a weak position. The duty is to flag it, not to redesign it.
Order of precedence: the clause that usually settles the argument
Every serious construction contract contains an order of precedence for the contract documents, and most owners have never read theirs. It ranks the agreement, the supplementary conditions, the general conditions, the specifications and the drawings, and it tells you which one wins when two of them disagree. A common convention is that specifications govern over drawings for quality of materials and workmanship, that figured dimensions govern over scaled dimensions, and that larger scale details govern over smaller scale ones.
Read that clause before you sign, not after the wall is open. If it is silent, or it has been quietly amended in the supplementary conditions, you have discovered a real risk while you still have the leverage to price it.
The RFI is a clock, not a formality
Once drawings and field conditions conflict, the mechanism is the request for information. What owners consistently underestimate is that an RFI starts a clock, and the clock costs money whether or not anybody is working.
A crew standing down for three days while an RFI sits in an inbox is a real cost, and it is often a compensable delay. The contract typically gives the consultant or design-builder a reasonable period to respond, and reasonable is doing a great deal of work in that sentence. At the pre-construction meeting, agree on a target turnaround for routine RFIs, a shorter one for anything that stops work, and one named decision-maker on your side who can answer without convening a committee.
Concealed and unknown conditions are a separate category
There is a real difference between a drawing that was wrong and a condition nobody could have found. Standard contracts handle the second case under concealed or unknown conditions: where site conditions differ materially from what could reasonably have been anticipated, both the contract price and the contract time can be adjusted, provided notice is given promptly.
Promptly is the operative word. These clauses almost always carry a short notice period, and a claim raised a month later is a much harder claim. This is also where a pre-construction allowance earns its keep. Carrying a realistic allowance for existing-conditions discovery in an older building is not padding a budget. It is the difference between a decision and a crisis.
Five moves that keep a field conflict from becoming a claim
Invest in investigation before you invest in design. Selective demolition, scanning, a proper survey and a services locate cost a fraction of the change orders they prevent.
Read the order of precedence clause. Know which document wins before you need the answer.
Name one decision-maker. Give that person authority to approve a defined dollar value on the spot.
Set RFI turnaround targets in writing. Separate the ones that stop work from the ones that do not.
Carry an honest contingency. Five per cent on new construction, and considerably more on a renovation of an older building, is discipline rather than pessimism.
The honest summary
When drawings and field conditions do not match, responsibility is not decided by who noticed first. It is decided by your delivery model, your order of precedence clause, your notice provisions, and how quickly your side can make a decision. Every one of those is settled before construction starts, which is exactly why the most valuable conversation about field conflicts happens months before anyone opens a wall.
Common questions about drawings and field conditions
Who is responsible when drawings do not match field conditions?
It follows the delivery model you chose, and it was settled long before the conflict appeared. If you hired a consultant and tendered their drawings, you handed over the design and you carry it. Under a design-build agreement the design-builder carries both design and construction.
How much is an as-built drawing actually worth?
Less than most owners assume. Most sets labelled as-built are the last issued-for-construction set with a few markups, and changes made late in the field rarely make it back onto paper.
How quickly should an RFI be answered?
Fast enough that nobody stands down. A crew waiting three days while an RFI sits in an inbox is a real cost and often a compensable delay. Set turnaround targets in writing, and separate the RFIs that stop work from the ones that do not.
How do I reduce this risk before construction starts?
Invest in investigation before design: selective demolition, scanning, a proper survey and a services locate. Then read the order of precedence clause, name one decision-maker with authority to approve a set dollar value on the spot, and carry an honest contingency.
If you are weighing how to set a commercial project up, that is the conversation I have with clients every week. You can see how I work with owners and project partners on project solutions, or simply start with a straightforward call.
This article is general information about commercial construction practice in Canada, not legal advice. Have your own counsel review your contract.
Connect with Carolee on LinkedIn: linkedin.com/in/carolee-w-turner-2002417
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