Letter of Exemption (LOE) for Mezzanine and Racking Installations

A Letter of Exemption (LOE) is sometimes requested when warehouse racking systems or mezzanine platforms are installed in industrial and commercial buildings across Ontario. The letter is issued by a professional engineer to confirm whether the proposed installation requires a building permit or structural review under the Ontario Building Code (OBC).

In many warehouse projects, storage systems such as pallet racking may appear structural but function as equipment installed within an existing building. A Letter of Exemption helps clarify that the installation does not affect the building’s structural system and may not require a structural permit.

Regulatory Context in Ontario

The Ontario Building Code (OBC) regulates construction activities that affect a building’s structural system, occupancy, and life safety. Structural modifications typically require engineering design and a building permit.

When reviewing warehouse racking or mezzanine installations, engineers assess whether the installation affects regulated building elements, including:

• structural load transfer

• fire protection requirements

• building permit obligations

Structural work in Ontario must follow the design standards referenced by the OBC, including CSA standards for steel, concrete, and wood structures.

If a racking installation remains independent from the building structure and does not introduce regulated structural work, a professional engineer may issue a Letter of Exemption (LOE) confirming that a building permit is not required.

Typical Situations Where an LOE Is Requested

Municipalities, building owners, and contractors frequently request an LOE when installing warehouse storage systems that may appear structural but are typically considered equipment installations.

Common examples include:

• adjustable pallet racking systems

• bolt-together industrial shelving

• freestanding warehouse storage frames

• light equipment platforms that are not attached to the building structure

  
  

In these situations, the engineer reviews whether the installation:

• transfers loads to the building structure

• alters the structural frame of the building

• creates a new occupied mezzanine level

• affects fire separations or required exit routes

If none of these conditions apply, an engineer may issue a Letter of Exemption for warehouse racking or mezzanine installations.

When a Mezzanine Requires Structural Design Instead

Not all elevated platforms qualify for exemption. Many warehouse mezzanines are considered part of the building structure under the Ontario Building Code.

A structural permit is generally required when the mezzanine:

• supports occupancy loads from personnel

• is connected to the structural framing of the building

• requires stairs, guardrails, or fire separations

• adds significant structural loading to the building system

When a mezzanine creates additional floor area used for occupancy or operations, it must comply with building classification and life-safety requirements under the Building Code.

In these situations, a Letter of Exemption cannot be issued, and a full structural design package prepared by a professional engineer is required.

Engineering Review for Racking and Mezzanine Installations

Before issuing a Letter of Exemption (LOE), an engineer typically reviews several technical aspects of the installation.

These reviews commonly include:

• installation drawings or supplier specifications

• anchoring details connecting racking frames to the concrete slab

• the capacity and condition of the warehouse floor slab

• potential interaction with building columns, walls, or framing

The objective of this engineering review is to confirm that the installation remains independent from the structural system of the building and functions as a storage system rather than a structural component of the building.

Typical Evaluation Factors

Review Item	Engineering Consideration
Load transfer	Whether storage loads are transferred to the building structure
Anchoring	Type of anchors used and concrete slab capacity
Structural attachment	Any connection to building columns, beams, or roof structure
Occupancy	Whether the installation supports people or only stored materials
Code classification	Whether the system could be considered a mezzanine under the OBC

Why Municipalities Request a Letter of Exemption

Municipal building departments often request engineering confirmation when warehouse racking or storage systems are installed inside existing buildings.

A Letter of Exemption helps clarify whether the installation constitutes regulated structural construction under the Ontario Building Code.

Providing this documentation can help:

• clarify whether a building permit is required

• document that a professional engineering review has been completed

• support municipal inspection processes

• avoid unnecessary permit applications for non-structural warehouse installations

For many warehouse upgrades, a Letter of Exemption for racking installations helps streamline project approvals.

Conclusion

A Letter of Exemption (LOE) for mezzanine and warehouse racking installations helps determine whether storage systems fall within the regulatory scope of the Ontario Building Code. The engineering review focuses on load transfer, structural attachment, and occupancy use.

When warehouse racking systems remain independent from the building structure, a Letter of Exemption can provide clear documentation for municipalities and building owners while avoiding unnecessary structural permit requirements.

At Parsways Inc., we provide engineering review and Letters of Exemption for warehouse racking and mezzanine installations across Ontario. Our reviews focus on clear engineering documentation, code-based evaluation, and practical coordination with contractors and municipal building departments.