In Canada, you can write off 3% of your house's value as an expense due to depreciation. If you do this, the CRA will hate you, they'll flag your account and they will check everything you submit, but it is legal. I know this from a fairly high-ranking friend in the CRA, and I've been filing this for over 5 years now. No trouble yet, and my accountant also assures me it's legal.
The reason they flag the account is that if you sell your house for more than
(original value) - (depreciation you filed)
you'll need to pay back taxes on all that depreciation. However, the CRA only keeps records for 5 years maximum, and in practice about 3, and the worst-case is in essence having gotten an interest-free loan from the Government of Canada (assuming you got enough money to foot the bill if you sell).