Canoe storage in detached garage - how hot is too hot?

I’m planning to be a first-time canoe owner in Sacramento (it’s 108F today, hot dry summers) and just about have all the questions I think need answered about how to store a canoe (e.g., out of direct sun, upside down on gunwales supported by saw horses, etc.).

So, I have a detached garage, metal door that’s about 20 X 20 ft and no roof vents. Needless to say, it gets hot in there (maybe 130 degrees at peak heat?). My plan is to store a 16 or 17 ft canoe in there (maybe an OT Camper in royalex or Bell canoe in whitegold).

I’m planning to install some passive roof vents this weekend.
One of my buddies said I need to get one of those solar attic fans (~$300) too.

How hot is too hot? Am I overthinking this or should I just dump the canoe in the garage and be done with it? Yay or nay on the solar attic fan?

Thanks in advance. Btw, this message board has been incredible.

If it’s a good canoe, I’d do what you are doing if I lived in such a hot climate. I can’t tell you it’s needed, only that it seems like a good precaution for a boat that you intend to keep for a long time. Still, the degree to which you want to lower peak temperatures might depend on a couple things.

First, what is the canoe made of? My hunch is that Royalex will age more rapidly in hot temperatures than most composites, but others here might have better-founded knowledge in that area than I.

Second, are you hanging it from the rafters or just setting it on sawhorses or a wall rack? As you probably know, it will be hotter up by the rafter stringers, and MUCH hotter above the stringers, though you probably can’t get the boat up into that space.

Installing some kind of vent lower than the roof to let air in from the outside will greatly improve the efficiency of roof vents, even for a fan-driven attic vent. I thought of doing that once when I was considering installing roof vents, and my plan was to install a vent in the entry door, and perhaps even provide it with a fan blowing inward. I figured that putting a vent in the door would be easier and much less intrusive than doing so in the garage sidewalls.

You need the vent in roof where heat rises too. I would put vent in door also. As air rises and exits the roof new air will be pulled through the door.

If you google “Royalex heat tolerance” and “Royalex molding temperature” you’ll find info that suggests you are fine up to about 200F and that the glass transition temperature is around 220 (the temp at which the material starts to change properties). There is a 56 page Mad River canoe care manual that says they have only rarely seen problems with canoes wrapped in their original plastic wrap and then left in the sun. So I think you are fine. You could call Nova Craft and talk to someone that’s been there a while to build more confidence. I think lots of canoes must see relatively high storage temps and customers would get grumpy (and post on the Internet) if their boats deformed during normal storage. You might put a thermometer in your garage on a hot day to get a better estimate around how close it gets to 200F. There are warnings about storing Royalex in direct sun since the skin may become brittle from uv exposure but you would not have that concern. A composite boat should be even more robust. The Northstar is an incredibly fine boat and the price is reasonable so my take is spend your money on the Bell instead of expensive ventilation systems.

All good points, Tom. What I was thinking, in terms of potential problems with Royalex boats, was not heat damage, but “accelerated aging”, since, if I remember my basic chemistry from eons ago, most chemical reactions double in speed for each rise in temperature of 10 degrees C. I figure if that holds for the “age-degradation” process, avoiding such high storage temperatures would be good in the long run to delay the onset of eventual brittleness, but probably not something you’d notice over a span of a year or two or maybe even several. Avoiding hot storage is the standard recommendation for things made of various other materials which eventually degrade over time, such as tires, to name just one.

Thank you for all the great advice, especially this piece: “The Northstar is an incredibly fine boat and the price is reasonable so my take is spend your money on the Bell instead of expensive ventilation systems.”