Two areas we are working on:
- What type of flooring can we install that won’t delaminate or crack in that kind of cold? Apparently stick down vinyl will not work.
- how do we better mouse proof for the winter? Currently we remove all food and bedding, put tinfoil on all counter/ledge surfaces, tip up/wrap mattresses. Plus we’ve added a fair bit of spray foam they haven’t seemed to chew thru yet. Anything I’m missing?
Flooring: Ceramic Tile or pine flooring (TnG) should both work fine. Basically think of the flooring you also see used in people's unheated (3-season) porches and consider using that. That said, we used trafficmaster peel-and-stick vinyl in our unheated terrace and it worked fine, even when it was -25ºC out there. YMMV
Mice will get into any undefended space. Removing all food and bedding is a good start, as is sealing up any obvious holes. Cut back any brush near the house too. I've heard of people using bottled cat-urine around the perimeter of their chalets in Quebec to deter all vermin from entering in the fall. Downside is if you spray it near any openings the next spring your home smells like cat piss. I've heard peppermint oil also works (and smells better).
If you don't care about killing the rodents you can put poison pellets down, but then you come back in the spring to mummified mouse corpses. Still, might be better than mouse-poop and finding they've gnawed their way through the walls.
