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Adding a dormer = new ventilation required?

jonathanforddalton | Posted in Building Code Questions on

Two friends of mine – one the building owner and the other a contractor – have been renovating an attic and plan to add a 10’x10′ dormer. After providing engineering drawings at great expense, our city’s building department is now asking for a ‘ventilation plan’ among other things, in order to get the permit.

It’s an old building with no active ventilation in Hamilton, Ontario, Canada. Presumably the Ontario Building Code would mandate the ventilation. I suspect however that my friends are being jerked around by the building department.

Has anyone even heard of having to retrofit the whole building’s ventilation in order to add a dormer?

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Replies

  1. GBA Editor
    Martin Holladay | | #1

    Jonathan,
    The place to ask your questions is at your city's building department. They're the ones you need to satisfy.

    Make sure that there is no misunderstanding: Do they want you to provide ventilation above the roof insulation (that is, soffit-to-ridge ventilation)? Or do they want you to install a mechanical ventilation system (fans) to supply fresh air to your indoor space?

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