Jo-Anne Stead and Paul Fecser had always agreed that someday they would need an addition to their Alta Vista home. Now, with two growing children, they knew the time had come to build an expanded, eat-in kitchen and a new family room. They spent more than a year in careful research, planning and design: working through their ideas for the size and function of the space, having architects develop concept and working drawings, hiring an interior designer to help them navigate style and colour choices, and then interviewing and selecting a general contractor.

The couple applied for a building permit in April 2004. Work began at the end of May and was completed about four months later, with final inspection in late October.

Mr. Fecser and Ms. Stead love the addition, which gives them an extra 400 square feet of window-filled living area so they can finally enjoy their southern exposure. “It’s one thing to see the space on paper,” Paul Fecser says. “It’s something else to live in it and enjoy it.” Although they feel the process might have taken less time if they had renovated before, they believe the detailed planning paid off. “You minimize surprises by planning,” Mr. Fecser notes.

Experts agree. No matter what type of renovation you’re considering, learn all you can about it, develop a clear idea of what you want, what you want to spend, and where you’re prepared to compromise.

First, ensure that you have a safe, viable space to renovate. Make any necessary repairs, and if you’re finishing the basement, deal with moisture and ventilation problems. If you’re building an addition, check your property survey to see what area is available for construction.

Next, decide the purpose of your space and how it could evolve with your needs. Taking the long view is especially important for basements, which offer open spaces with the potential for zones of use, says Norm Lecuyer of Just Basements. “My basement started out as mine, then it became my kids’ basement — first as a play area, now as a space for computers and air hockey. Eventually it will become a space for my wife and me again. Plan for this kind of evolution.”

Once your ideas have gelled, draw up a detailed plan or have a professional do it for you. This helps ensure that you and the contractor you hire understand the project the same way. It also allows you to obtain more reliable price quotes. “If you don’t have detailed plans or specs, you wind up telling different things to different people,” says contractor Marco Disipio of Chimere Canada. “That’s not a good basis for comparing costs.”

Make sure you hire a reputable, professional contractor. Find out how much experience the person has with the type of project you’re planning and check references and insurance coverage. Above all, pick someone you can work with. “Chemistry is important,” says Robert Cronier of Fuoco-Cronier Construction and Renovation, who built the addition to the Fecser-Stead home. “To avoid problems, you have to be able to communicate with your contractor.”

Next, prepare a detailed contract that spells out everything, including time penalties, payment schedules, responsibilities, and how you’ll handle change orders. Because there will be changes, no matter how much you plan. The renovation may uncover a plumbing or electrical problem, materials may be delayed, or you may change your mind about finishes. “Go with the flow,” advises Norm Lecuyer. “It’s important for managing stress levels.”

Because changes are inevitable, accept the fact that your project will take longer than you think and involve costs you didn’t foresee. For example, Paul Fecser and Jo-Anne Stead’s job exceeded the original budget by 20% because of repairs that had to be made to their existing roof and a decision to upgrade to a granite counter for the kitchen island.

Your planning should also include a strategy for coping with the disruption to your daily life. Ms. Stead and Mr. Fecser timed their renovation for the summer so they could cook on the barbeque when they were without a working kitchen and take holidays when the work was most intrusive.

“We’re glad it’s over,” Ms. Stead says. “It’s trying sometimes to have people in your house. But we’re happy with the results.”

“The best advice I could give about renovating is to know what you want,” Mr. Fecser adds. “Research everything so you can make good decisions. And find a contractor you can communicate with. There are always decisions to be made and always surprises, so you need to talk or meet often.”