What permits do you need to build a boathouse?

Do I need a building permit to build a boat house?

Yes. And in most municipalities, boathouses need to be designed or approved by a structural engineer.

Do I need an MNR work permit?

Maybe. “If you’re working around water, just tell us what you’re planning,” says Ariel Zwicker, a senior lands and waters technical specialist with the MNR in Bracebridge. “We can advise you whether a permit is required.” Under the Public Lands Act, you can only build 15 square metres of cribbing—certainly not enough for a boathouse—without a work permit. Even adding a small crib to an existing structure needs an MNR work permit if old and new cribs are more than 15 square metres.

To apply for a work permit, you’ll need a site plan or a survey outlining the project. The MNR will do a review, consulting Fisheries and Oceans Canada, and may tell you when you can do the work, where exactly you can build, and sometimes even how.

In some cases, the application will be denied outright. Count on the entire process taking from six to 12 weeks.

New boathouses on steel piles or floats don’t need an MNR work permit. And as long as the lake bed is undisturbed, neither a crib repair nor a boathouse or crib demolition needs an MNR work permit (though you’ll need a municipal demolition permit).

Can I rebuild the old boathouse?

Probably. In most municipalities, cottagers with existing boathouses can repair or even rebuild “grandfathered” structures, using the same footprint as the older boathouse. It doesn’t matter if that footprint is larger than what current standards allow, or if the boathouse has a second storey in an area where new boathouse living spaces are forbidden. Known as “legal non-conforming,” it’s a reward for surviving to old age.

When an old “legal non-conforming” boathouse is kaput, a common solution (no work permit needed) is to drive steel piles around the existing cribs and simply construct a steel frame, designed by a structural engineer, that straddles the old substructure and supports a new boathouse. You can remove timbers from any cribs that interfere with the new structure, but crib stones must be left in place.

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