Is a Secondary Suite Worth It?

Many people are looking at secondary suites as a way to make a new home more affordable. There are many questions to consider. Do you really want to share your new house? What design issues do you need to consider when designing your home plans? Do the rewards outweigh the financial costs of constructing a secondary suite?

Sharing Your New House

Including a secondary suite in your new home plans can be a cost savvy way to make your dream home a reality. To make the best of it, consider these few items:

Providing private entrances for you and your tenant allows you to control when you interact with them. Starting outside, consider where they will park, what part of the yard they will walk through and what windows they will walk past. Once in the home, it is ideal to give the tenant direct access into their space.
It is inevitable that your tenant will want to barbeque or sit outside to enjoy a sunny day so you may want to think about providing them with an outdoor space, the size of which is up to you. You should ensure that your outdoor spaces are as private from one another as possible.

Think about minimizing noise transfer between your space and the secondary suite. The National Building Code establishes minimum Sound Transmission Class (STC) ratings between the home and a secondary suite. However this is one area you would be best to exceed code minimums.

Design Considerations

These are a few additional things to consider when incorporating a secondary suite into your home plans:

Ensure adequate storage space for you and your tenant. While the basement is the most common location of a secondary suite, it is also used by most for additional storage. If you are building a bungalow you are guaranteed to have some basement space for yourself as the maximum secondary suite size is the least of 862 sq. ft. or 40% of your total house area (including the basement). However with a two storey, it is possible that the suite takes up the entire basement.

Provide access to laundry and mechanical equipment. While providing laundry for your tenant is not a requirement, it is a good selling feature. You can do this with shared or separate laundry spaces. You have the same options with mechanical equipment (shared vs separate). The only building code requirement is that you can access the mechanical equipment without going through the suite.

Decide what part of your home the secondary suite will be in. While most secondary suites are in the basement, you can have them anywhere in your home. Depending on your property, size of home or foundation requirements, the second floor, a portion of your main floor or the space over your garage may be a more suitable location. Also some cities have begun to allow Accessory Dwelling Units (ADU’s) which are a second residence on your property. Consult local city officials for the potential for and requirements of ADU’s in your area.

Financial Costs

Along with the obvious requirements of additional kitchen and laundry spaces for your tenant, there are a number of building code requirements that will increase the cost of construction as compared to conventional construction:

Mechanical ducting cannot be shared between your space and a secondary suite. Most HVAC systems use ducted systems to distribute heat, air conditioning and fresh air. This means you will have to provide a second heating system and air exchanger for the suite.
There are additional requirements for the walls and floors separating the home and its secondary suite. A smoke separation is required between spaces but is simply a matter of ensuring a continuous layer of finished drywall. However the STC rating requires insulation to be added to the wall and floor cavities and sound deadening metal channels between the framing and drywall.
The amount of additional area you finish will increase the overall cost of your home and the amount of above ground floor area you require may increase if the suite is in the basement. You would be wise to compare the additional costs involved with the average rental rates in your area. This will give a better idea of your actual savings and may affect how large the suite needs to be based on potential revenue from a bachelor, one bedroom or two bedroom suite (which is the maximum number of bedrooms the building code allows).

It is evident that considering a secondary suite in your new house requires much thought and contemplation, however, as a new home owner, only you can decide if it is worth it!