Date of Publication: July 16, 2025 [2022.06.V-02.C]
Subject: Renovations to Mobile Homes – 2024 OBC UPDATE
Summary of updates: Updated sentences. No changes to recommendations.
2024 Ontario Building Code [O.Reg 163/24 Amended to 5/25] Reference(s):
Sentence 1.3.3.3C.(1) of Division A
Sentence 3.5.2.1.(1) of Division C
Incoming Request:
Some mobile homes and or park model trailers, undergo renovations or have additions attached to them over time, none of which are covered by their original CSA certification. Since it is not reasonable or realistic to deny permits in all cases, what precautions should be taken and what type of documentation should be requested for various types of work, i.e. a new roof?
To what extent can renovations and/or additions be made to a manufactured home or park model trailer before the original certification under the governing standard has been invalidated?
Executive Summary:
Additions and renovations can take several forms, each of which have their own considerations. Due to the range of possibilities, care should be taken in reviewing applications for additions or alterations to a mobile home or park model trailer.
The type of connection for additions and the extent of proposed renovation within the existing structure will, to a large extent, dictate the approach to the requirements to be imposed.
Discussion & Considerations:
There are many variations of additions and renovations which could be considered, so this guidance will address very general scenarios. In all cases, very clear plans detailing the proposed additions and/or alterations are required. As with any building, only the new work will be required to comply with the OBC (sentence 1.3.3.3C.(1) of Div A).
The first scenario is an addition connected to the existing building by a flexible construction joint rather than a hard, physical connection (the addition is structurally independent of the existing building). Where no changes are being made to the existing building envelope, no engineering verification of the existing structure’s ability to handle addition loads or stresses would be required, since the loads and/or stresses of the addition will not be transferred to the existing building. In those cases where new openings in the existing building envelope are being proposed, a review of the structural integrity of the structure from either the original certifying body or a suitably qualified person may be required due to the changes to the lateral shear resistance and other structural characteristics.
The second scenario is an addition connected to the existing building by a hard, physical connection. In these cases, verification of the ability of the existing structure to handle addition loads or stresses imposed by the addition would be required from either the original certifying body or by a suitably qualified person. This would include an addition physically attached to the existing structure, including open decks. Additionally, care should be taken for additions which could significantly impact the snow loading on the existing roof assembly.
The last scenario is a renovation contained entirely within an existing structure. Although structural issues are unlikely to be of any concern, plumbing and/or HVAC changes could be of concern. Clear, detailed plans are required to be able to properly determine the extent of the proposed alterations and their impact on the existing systems. As with any other existing building, Part 11 should be used where the building is more than 5 years old. Again, for proposed new openings in the building envelope, a review of the structural integrity of the structure from either the original certifying body or a suitably qualified person may be required. A suitably qualified person can be a P. Eng. or a designer with structural qualifications (per Sentence 3.5.2.1.(1) of Div.C) who provides detailed design or analysis calculations showing conformance with Part 4 of the OBC.
Risk/Benefit Analysis:
This guidance carries minimal risk as it is a clear application of the Code. As stated earlier, a manufactured home or park model trailer may not be constructed using commonly seen building materials and methods. Expertise will be required on the part of the designer and builder.
Final Recommendation(s):
Renovations to manufactured homes or park model trailers must consider the existing structure and how the modifications will affect it. One cannot assume typical construction methods and materials. Clear, detailed plans will be required, and very likely some form of professional design.
Referenced Documents:
2024 Ontario Building Code [O.Reg 163/24 Amended to 5/25]:
Sentence 1.3.3.3C.(1) of Division A
Sentence 3.5.2.1.(1) of Division C
Disclaimer:
This guidance document is intended to assist building officials by gathering relevant information to interpret the OBC Act and the prescriptive requirements of the Ontario Building Code, and is intended to be a best practice aid for building officials.
The views expressed within this guidance document should not be considered as the official interpretation of legislated requirements based on the Ontario Building Code, as the final responsibility for interpretation rests with the local Authority Having Jurisdiction.
The views of this advisory committee should not be construed as legal advice.