Quick Answer: Ontario archaeology generates artifact assemblages a licensee must curate, box-counted, until deposit, and metals corrode fast in the wrong humidity. All iron rusts above about 65% RH; a secure insulated container holds the 35-55% band with a sub-35% zone for active corrosion. We sell the room, not the conservation. Delivered in 1-3 days.
In This Guide
Reading Time: 9 minutes
The Box Count Is a Licence Obligation
Licensed archaeology in Ontario produces something the public rarely thinks about: volume. Every Stage assessment that recovers material generates an artifact assemblage that has to be cleaned, catalogued, boxed, and curated, sometimes for years, until it is deposited with the Crown or an approved repository. The 2011 Standards and Guidelines make this a formal, licence-level obligation: the project report must state the size of the packed collection, the number and size of boxes, and the long-term curation plans, and the packed catalogue must list artifacts by box. This is not optional storage; it is a documented condition of the licence.
The wider collections version of this problem sits in our museum and archive storage guide.
For a consulting archaeology firm, that assemblage sits in their custody, indexed box by box, taking real space and real responsibility. A cramped office, a shared unit, or a leaky outbuilding is where too many assemblages end up, and the same standards concede that storage-driven deterioration of unstable artifacts is a real risk the licensee must document. A secure, dry, insulable container on the firm’s own yard is a purpose-fit answer to a licence obligation, and that is the honest frame for this page.
Why Excavated Metal Is a Ticking Clock
Most of an assemblage, the lithics, ceramics, and stone, is robust and needs security and dust exclusion more than a tight climate. The metals are the problem, and excavated metal is worse than any metal you buy. The Canadian Conservation Institute states it flatly: all iron rusts when relative humidity is over about 65 percent, and while uncontaminated iron is stable at 50 percent, iron contaminated with salts keeps corroding even there. Archaeological iron came out of the ground full of salts, so it is on a corrosion clock that only drops when the humidity does.
Copper alloys carry their own hazard, bronze disease, an active corrosion of archaeological bronzes that has to be segregated and held below 35 percent RH to slow it. And here is the practical trap the CCI names: a domestic dehumidifier cannot get relative humidity below about 40 percent, so the sub-35 percent zone needs silica gel or a desiccated micro-enclosure. A sealed container is exactly the shell that makes such a dry micro-zone practical, which a leaky room never could.
Christian LeBlanc, second-generation operator: “We treat these like the museum jobs, carefully. The firm is legally holding those boxes, and the metals are corroding on a humidity clock. We give them a secure, dry, sealed room; their conservator sets the numbers and runs the desiccant zone for the bronzes.”
The Humidity Bands Metal Curation Needs
| Material and condition | What the conservation guidance specifies |
|---|---|
| Stable metals with the general collection | 35-55% RH; move to controlled storage if RH exceeds 55% |
| Iron, uncontaminated | Stable at 50% RH; all iron rusts above about 65% |
| Iron, salt-contaminated (excavated) | Keeps corroding even at 50%; wants the dry end held |
| Active corrosion / bronze disease | Segregate and hold below 35% RH; needs desiccant, not a domestic dehumidifier |
| Bulk lithics, ceramics, stone | Security and dust exclusion; keep RH off the damp line |
The whole assemblage rarely needs one tight setpoint. It needs a secure, insulated room holding a moderate band for the bulk, with a small, drier, desiccated zone inside for the vulnerable metals. That is a build a container suits precisely.
A Dry-Box Bulk Store With a Conditioned Metals Cabinet
The economical, honest configuration for most firms is a two-zone one. An insulated container gives the secure, weather-tight, lockable shell for the whole assemblage, holding the moderate band that protects the bulk lithic and ceramic material and keeps RH off the 65 percent iron line. Inside it, a small conditioned cabinet or desiccated micro-enclosure holds the sub-35 percent zone for active-corrosion metals and bronze disease. For a firm with a mostly robust assemblage, a well-sealed dry box plus a desiccant cabinet is often the whole answer; a firm with significant metal holdings leans to a fully insulated build. We fit the insulation, shelving, and surfaces at the yard as a standard insulated conversion; the conservator specifies the RH targets and the segregation protocol.
A Curation Store That Meets the Obligation
Tell us your assemblage volume and your metals load. We will spec the secure shell and the conditioned-cabinet zone, then your conservator sets the numbers. Honest quote, same day.
Custody, Deposit, and What We Do Not Touch
The honest line, stated clearly because heritage is regulated. We sell the secure, dry, lockable room, steel, weather-tight, insulable, alarmable, on the consultant’s own yard. We do not do conservation treatment, and we do not take custody of artifacts. Ownership, safekeeping liability, cataloguing, and the eventual deposit with the Crown or an approved repository remain the licensed archaeologist’s legal responsibility under the Ontario Heritage Act and the 2011 Standards and Guidelines, and the conservator sets the humidity targets and the segregation protocol for unstable metals. We do not claim the container preserves or conserves artifacts; it houses and secures them to the environment the institution specifies.
Delivery runs one to three days, which is usually faster than the assemblage paperwork it is going to hold. The museum and archive storage page covers the broader collections version of this, and the hub comparing a container to the alternatives frames the buy. Firms are welcome to bring their conservator to walk an insulated build at the yard.
Frequently Asked Questions
What humidity do archaeological metals need?
Stable metals sit at 35 to 55 percent RH and should move to controlled storage above 55 percent. All iron rusts above about 65 percent, and salt-contaminated excavated iron keeps corroding even at 50 percent. Active corrosion and bronze disease need segregation below 35 percent RH.
Can a shipping container store an artifact assemblage?
Yes, as a secure, dry, lockable room on the firm’s own yard. An insulated container holds a moderate band for the bulk assemblage with a desiccated cabinet inside for vulnerable metals. It houses and secures artifacts; the conservator sets the climate and the archaeologist keeps legal custody.
Is storing an assemblage a legal requirement in Ontario?
Yes. The 2011 Standards and Guidelines require the licensee to report the packed-collection box count and long-term curation plans, catalogue artifacts by box, and hold the assemblage until deposit with the Crown or an approved repository. Proper storage is a licence-level obligation.
Why can’t a regular dehumidifier protect bronze artifacts?
Active corrosion and bronze disease need relative humidity below 35 percent, and a domestic dehumidifier cannot reduce RH below about 40 percent. That sub-35 zone needs silica gel or a desiccated micro-enclosure, which a sealed container makes practical inside the secure store.
Does Van Blanc conserve or take custody of artifacts?
No. We supply and deliver the secure, insulated room only. Conservation treatment, cataloguing, custody, and the eventual deposit remain the licensed archaeologist’s responsibility under the Ontario Heritage Act and the Standards and Guidelines. The conservator sets the humidity targets; we build the room to them.
Sources
- Canadian Conservation Institute. CCI Notes 9/2, Storage of Metals. canada.ca
- Government of Ontario. (2011). Standards and Guidelines for Consultant Archaeologists. ontario.ca
- Government of Ontario. Ontario Heritage Act, R.S.O. 1990, c. O.18. ontario.ca
- Canadian Conservation Institute. Incorrect Relative Humidity (Agents of Deterioration). canada.ca
- International Organization for Standardization. (2019). ISO 1496-2, Series 1 freight containers: thermal containers. iso.org
Reach Van Blanc in Brantford
We have supplied and converted secure, insulated containers across Ontario since 1995. Bring your assemblage volume and your conservator, and we will talk secure shell, the conditioned metals zone, and where our work ends.
Van Blanc Ent. Inc., 90 Morton Ave E Unit 1B, Brantford, ON N3R 7J7. +1 888-509-6658
Firms are welcome to bring their conservator and look at how the metals zone would actually sit inside.