It applies to Canada as well. Claim 25% of your home as a business expense means 25% of any capital gains are taxed, unlike your primary residence which isn’t taxed.

“You may have to report a capital gain if you change your principal residence to a rental or business property, or vice versa.”

https://www.canada.ca/en/revenue-agency/services/tax/individ...

However, it looks like there were some changes that may allow you to avoid it (business use was a small fraction and you didn’t take advantage of tax benefits from business use).

I don't think you get to write off work expenses as a W2 (ie, hourly or salaried) employee in the US. pretty sure only independent contractors get to do this. otherwise, everyone would be doing this for commuting expenses.

(At least in Canada) commute to your "usual place of business" is explicitely excluded from write-off. Also, if your employer reimburses you for travel (mileage) you can't write it off at tax time.