Why conflicts are inevitable
Three structural causes, independent of the care taken. They stem from the number of documents and their authors.
The documents are written at different times. A specification drafted six months before the construction drawings cannot account for them.
They are written by different authors. Architect, engineer, quantity surveyor and contractor share neither vocabulary nor conventions.
They have different levels of detail. A drawing and a description do not say the same thing about the same work, and the precision of one may contradict the generality of the other.
No amount of rereading removes that risk, as developed in the guide on measurement and specification.
What a hierarchy resolves
It does not remove conflicts; it determines which prevails without discussion. The hierarchy clause therefore gains from being explicit.
Absent a clause, a conflict is resolved by interpretation. The court seeks the parties' common intention, relying on general rules and the circumstances. The outcome is uncertain for both.
With a clause, the conflict is resolved by reading. The higher document prevails, and the discussion turns at most on whether a conflict exists, not on its outcome.
The gain is therefore not winning, but knowing. A written hierarchy lets each party assess its position before incurring costs.
The order usually adopted
There is no statutory hierarchy in private contracts, but one order recurs in practice. That order is usefully restated in the contract.
| Rank | Document |
|---|---|
| 1 | the agreement itself and its addenda |
| 2 | documents specific to the contract |
| 3 | drawings and graphic documents |
| 4 | descriptions and specifications |
| 5 | general or standard documents referred to |
The underlying principle is that the more specific prevails over the more general, and the more recent over the older.
Two useful qualifications. The relative rank of drawings and descriptions varies by contract and deserves conscious decision. And mentioning addenda is essential, failing which an accepted variation may be contradicted by an original document.
In public contracts
The position differs, and that must be known. Public contracts follow their own rules.
Contract documents generally include a hierarchy, and the rules further frame how documents interact, covered in the guide on measurement and specification. That framework narrows the room for argument.
The reasoning is the same, but the margin of freedom is narrower and some derogations require formal reasons.
What happens when the clause is missing
Three practical consequences, all unfavourable. They arise where no hierarchy clause exists.
Time. A dispute about interpretation takes months, sometimes with expert evidence, whereas a written hierarchy is read in a minute.
Cost. Uncertainty about the outcome pushes towards settlement, generally to the detriment of whoever has less cash.
The cascade effect. An unresolved conflict on one point produces others, each party continuing to work on its own reading.
The clause runs to three lines. It is one of the best ratios of drafting effort to risk avoided.
What this means for a professional
Four rules.
Write the hierarchy rather than assume it, even where it seems obvious.
Decide consciously on the rank of drawings and descriptions, according to the nature of the project.
Place addenda at the highest rank, without which accepted variations remain fragile.
Check the clause is consistent with the documents listed, a hierarchy citing non-existent items being unusable.
This article reflects drafting principles at the date of checking and serves professional orientation. It does not constitute legal advice and does not replace assessment of the individual case.