In-Law Suite Converting a garage into a full in-law or guest suite—or a guest house in the case of a detached garage—costs $20,000 to $50,000 on average. At the lower end of the range, a basic conversion will include insulation, drywall, flooring, and a bathroom.
Budget Considerations (Average Cost)
Once you know the requirements for your town or city, you can start thinking about the not-so-fun part of building a mother-in-law suite: the cost. According to Angi, the average cost to convert a garage into an ADU is between $20,000 and $60,000.
Converting a garage into a bedroom is a practical solution for changing family needs or accessibility concerns – (£10,000 – £20,000, with costs increasing if you add an ensuite). However, the price depends heavily on your chosen layout – (£20,500+ for integral double, £45,000+ for detached double).
Converting a Garage, Basement, or Attic
Converting a garage or basement is often ideal for an in-law suite since it already has framing and foundation. Expect to spend $20,000 to $60,000 to convert a garage and $10,000 to $30,000 to finish a basement.
Garage. Converting a garage into an in-law suite can be practical if you do not need that space for vehicle parking. You can do this with either an attached or detached garage.
Planning permission for a garage conversion is not necessary in many cases, although it is always best to double check with your local authority first. Most integral garage conversions fall under Permitted Development which means there is no need to make a planning application.
There may be tax credits for having an ADU or in-law suite. For instance, if you're paying for more than half of your relative's support, you may be able to claim them as a dependent. You may also qualify for a home office tax deduction if that's the in-law suite's primary use.
Features and Layout for ADUs
Size Considerations: The size of an in-law suite can vary greatly depending on the existing structure and the family's specific needs. On average, these suites range from 500 to 800 square feet, providing sufficient space for a comfortable, functional home within a home.
According to our prices, a modular single-car garage with an apartment ranges from $17,125 to $36,845 based on size and other additional features. You will pay approximately $38,658 to $59,018 for a two-car garage with an apartment space.
Typically, the cheapest type of garage conversion will just involve blocking up the garage doors and finishing out the walls, floors, and ceiling with insulation, drywall, carpet, or other flooring material.
On average, a garage conversion takes as little as 4-6 weeks. Compare this to a loft conversion (8-10 weeks) or rear extension (10-14 weeks) and you can appreciate why homeowners love how quickly this project can be turned around.
If you intend to convert the garage into a habitable space like a bedroom, living room, or self-contained flat, a building consent is generally required to ensure the renovation meets the Building Code standards.
On average, a garage conversion costs between £18,000 and £28,300. Keep in mind that cost of labour is higher in London and the Southeast, sometimes by up to 20% on average. A garage conversion could add a lot of value to your home.
Building a mother-in-law suite could also offer certain tax benefits. How many square feet is a typical mother-in-law suite? Mother-in-law suites can vary in size but are typically about 500 square feet.
Since California has passed the new ADU laws this year, usable rooms like garage conversions can be used as a source of passive income. Even if you're only planning on converting the garage to an additional bedroom or home office, permits will be needed for residential construction.
Overall, building an in-law suite can be a smart investment for homeowners who weigh the costs and benefits and plan for the long-term. With the potential for rental income and increased property value, it can provide a comfortable living space for family members while also generating additional income.
A mother-in-law house plan typically includes a bedroom, bathroom, and living/kitchen area separate from the rest of the home, whether on its floor or an independent property structure.
The cost of building an in-law suite can vary widely depending on factors such as size, location, materials, and local labor costs. On average, it can range from $50,000 to $250,000 or more.
According to Porch.com, when ADUs are located on properties in major cities with high housing costs, an ADU can add as much as 35% to the value of a property.
Home renovations typically do not qualify for federal tax deductions, but certain improvements may qualify for deductions and credits can help reduce taxes. Financing home improvements through your mortgage may allow you to claim the interest as a mortgage interest deduction.
The potential dependent must be one of these: Your parent, ancestor (ex: grandparent, great-grandparent), or sibling of either of them. Stepsibling, stepparent, parent-in-law, son- or daughter-in-law, or brother- or sister-in-law. Any person that lived with you for the entire year as a member of your household.
In-Law Suite
Converting a garage into a full in-law or guest suite—or a guest house in the case of a detached garage—costs $20,000 to $50,000 on average. At the lower end of the range, a basic conversion will include insulation, drywall, flooring, and a bathroom.
Generally, building up is usually more cost-effective for new construction, while building horizontally tends to be less expensive for remodeling existing homes.
If you know the unit will sit vacant for a while, an in-law unit can be turned into a more traditional rental, with long-term monthly or even yearly leases.