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Tier III · Tier IV · Mission-Critical

Data Centre
Construction in Ontario

Terrahills delivers data centre and mission-critical facility construction in Ontario to Tier III and Tier IV standards. Concurrently maintainable and fault-tolerant infrastructure, structure and envelope designed for the equipment, physical security built in, and commissioning to the standard before handover.

A data centre is an industrial building whose entire purpose is uptime. The shell (non-combustible steel or concrete, a high-performance envelope, a slab designed for equipment loads and vibration) is the part we build every day. What distinguishes it is what the shell has to support: redundant utility and generator power paths, UPS and switchgear rooms, cooling plant sized to a rack power density that keeps rising, raised floors or overhead distribution, and a physical security program that starts at the property line.

Tier III requires concurrent maintainability. Every component can be taken out of service for maintenance without taking down the load. Tier IV adds fault tolerance. A single failure anywhere does not interrupt operations. Those are design and commissioning standards, not construction techniques, and meeting them means the mechanical, electrical and structural consultants are coordinated from the first day and the commissioning agent is engaged before the equipment is bought. We manage that coordination and carry the whole scope: site selection against utility capacity and fibre, approvals, servicing, structure, envelope, and the integrated systems testing that proves the tier.

Ontario's advantage is power and climate. Grid capacity, cold-climate free cooling for a large share of the year, and land outside the GTA at county prices make Simcoe County, the 400 corridor and Eastern Ontario credible data centre locations, provided the utility connection is confirmed before the land is.

By adhering to Tier III and Tier IV standards, every data centre project meets the benchmarks for security, redundancy and availability its operator needs, with redundancy systems, power resilience and physical security designed in from the first coordination meeting rather than added later.

How we deliver data centres

Six stages, one contract

The same delivery model as every Terrahills project (land, approvals, servicing, structure, envelope, handover) applied to what a data centres building actually requires.

01
Site selection: power first

Utility capacity in megawatts, connection timeline and cost, fibre routes and diversity, confirmed in writing before land is committed. A site with cheap land and no power is not a site.

02
Tier decision & design coordination

Tier III concurrent maintainability or Tier IV fault tolerance decided from the cost of downtime; mechanical, electrical and structural consultants coordinated from the first meeting.

03
Approvals & servicing

Site plan, utility agreements and the generator, fuel and plant-yard approvals that a mission-critical facility carries beyond a standard industrial building.

04
Shell built around the plant

Non-combustible structure, high-performance envelope and a slab designed for equipment loads and vibration, sized to the plant, with structural provision for expansion.

05
Power, cooling & security installation

Long-lead switchgear, generators, UPS and chillers procured against the approvals calendar and installed in parallel with finishing; physical security built in from the property line.

06
Commissioning proves the tier

The commissioning agent engaged before equipment is bought; integrated systems testing (pulling feeds, failing components, holding the load) carried through to handover.

The full service list

Proof of delivery

Capability Data Centres

Our regulated-environment and industrial delivery, the EU-GMP pharmaceutical facility and the Ramara Industrial Park, is the foundation for mission-critical work: controlled environments, documentation to a standard, and one accountable contract for structure, envelope and systems.

Case studies & guides
From the blog
What it costs

Data Centres cost bands, Ontario 2026

Data centre cost is driven by tier, rack power density and the power and cooling plant, not by floor area. The building shell is a minority of the budget. published cost benchmarks publishes no per-square-foot band for it in the public excerpts of the 2026 Cost Guide, and a general figure would mislead. We produce a Class C estimate from the tier, the target IT load and the site's utility capacity.

FAQ

Questions clients ask about data centre construction

Tier III is concurrently maintainable: any component can be taken out of service for maintenance without interrupting the IT load, which generally means N+1 redundancy on power and cooling with dual distribution paths. Tier IV is fault tolerant: a single unplanned failure anywhere does not interrupt operations, which generally means 2N or 2N+1 with physically separated, independent systems. Tier IV costs materially more and is justified by the cost of downtime.
It is driven by tier, rack power density and the power and cooling plant rather than floor area. The shell is a minority of the budget. There is no useful per-square-foot band; we produce a Class C estimate from the tier, the target IT load in megawatts and the utility capacity at the site.
Power and land. Grid capacity is the binding constraint on data centre development, and Simcoe County, the Highway 400 corridor and Eastern Ontario offer utility capacity and land at county prices, with cold-climate free cooling for a large share of the year. The utility connection is confirmed before the land is bought.
We engage the commissioning agent before equipment is procured and carry integrated systems testing through to handover. A Tier III or IV facility is proven by commissioning, not by construction, and it has to be planned from the start.
Yes. The same discipline applies at 500 kW as at 20 MW. Redundant power and cooling paths, a shell designed for the equipment, security and commissioning to the tier. The scale changes; the delivery model does not.
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