It’s difficult to provide a definitive list of the top home renovation types by cost to return on investment (ROI) ratio in the Toronto area, as the ROI of a particular renovation can vary depending on a number of factors, including the condition of the home, the specific location, and the state of the local real estate market.

Home Renovation Projects That May Offer a Good ROI in Toronto

1. Kitchen remodel: A kitchen remodel can be a major investment, but it can also have a significant impact on the value of your home.
2. Bathroom remodel: Like a kitchen remodel, a bathroom remodel can be a costly undertaking, but it can also have a good ROI.
3. Adding a deck or patio: Outdoor living spaces are popular, and a well-constructed deck or patio can add value to your home.
4. Finishing a basement: If your home has an unfinished basement, finishing it can add valuable living space to your home and increase its value.
5. Installing energy-efficient windows: Energy-efficient windows can help reduce your energy bills and may be attractive to potential buyers.
6. Replacing the roof: A new roof can be expensive, but it’s an important home maintenance project that can help protect your home and increase its value.
7. Landscaping: Investing in landscaping can improve the curb appeal of your home and increase its value.
8. Painting the exterior: A fresh coat of paint on the exterior of your home can make it look more attractive and increase its value.
9. Replacing old doors and windows: Old doors and windows can be drafty and inefficient, and replacing them can improve the energy efficiency of your home and increase its value.
10. Adding a home office: With more people working from home due to the COVID-19 pandemic, a home office can be a valuable feature for potential buyers.
11. Installing a new HVAC system: A new HVAC system can be expensive, but it can improve the comfort of your home and increase its value.
12. Upgrading electrical and plumbing fixtures: Upgrading your home’s with new, more modern electrical outlets and plumbing fixtures can add to home and increase its value.
13. Replacing old appliances: Upgrading to energy-efficient appliances can improve the efficiency of your home and increase its value.
14. Adding a home security system: A home security system can provide peace of mind and may be attractive to potential buyers.
15. Adding a fence: A fence can provide privacy and security, and it can add value to your home.

One potential issue that may arise when planning a home renovation in Toronto is the need to obtain a permit. Depending on the scope of the renovation, you may need to apply for a building permit from the City of Toronto. 

The process for obtaining a permit can vary depending on the type of renovation you’re planning, and it may take some time to complete. It’s important to be aware of any permit requirements and to follow all necessary procedures to ensure that your renovation project is completed safely and in compliance with all applicable regulations.

It’s important to consider the costs and potential ROI of any renovation project before embarking on it, and to consult with a professional if you have questions or concerns.