Design & DIY

Cottage Q&A: Should I add a dormer to my cottage?

A dormer window on a tiled roof By U. J. Alexander/Shutterstock

I want to add a dormer to my loft. Is this something I should really be considering? My cottage is seven years old, and I purchased it new. It uses engineered rafters for its 12/12 pitch.—Stephen Godin, via email

Sure, you should be considering it. Who doesn’t love a dormer? Those things are cute! “The concept of a dormer with a chalet style is quite popular and doable,” says Marshall Black of Marshall Black Carpentry in McKellar, Ont. But whether or not you actually go through with it could depend on why you want it, how much it’s going to cost, and whether or not there are better options. 

You probably don’t want the dormer in order to let in more light since, based on the photos you sent us, it looks like there is already a good-sized window in the loft space, notes Dale Parkes, a professor in the architectural and engineering technology department at Thompson Rivers University in Kamloops, B.C. “So maybe the goal is getting more usable floor space?” That, or getting a bit more sleeping space, since, in our experience, every cottage could use more room for a few extra guests.

How can I add more sleep space at the cottage?

A roof pitch of 12/12 is not a problem, if that’s what you’re wondering. “The existing roof pitch is inconsequential when building a dormer. It just means the bigger the pitch, the more room created once dormered,” says Black. The issue, he says, will be in the design of the dormer and how it can be supported. “The point loads created will need to be transferred down to the existing foundation or, if needed, new piers installed to carry the load.”

These factors could affect the cost of the addition, along with how large it is and where it will go—for example, over a portion of the cottage where there’s an existing ceiling, which can then become the floor. “If there’s nothing underneath, you’ll need to put a floor in,” says Black.

Clearly, this isn’t a DIY job. It will require the help of a structural engineer, a designer, or both, “and that can get expensive,” says Parkes. 

Should I enlist my friends to help with cottage renovations?

On the other hand, unlike building a bunkie, “it’s saving you having to pour a foundation,” says Black, who adds that it could be more cost-effective than a reno that changes the cottage’s footprint. “When it comes to building, it’s often cheaper to go up than it is to go out,” he says. “That’s one reason why there are so many skyscrapers.”

This article was originally published in the June/July 2023 issue of Cottage Life. Got a question for Cottage Q&A? Send it to

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