When they bought the property, the Smythes wanted to move the garage to one side of the house, only to discover that the structure was in such bad shape it could not be moved.
They hired Mary Holland, of Cicada Architecture in Philadelphia, to design a workshop that would replace the garage and help improve the yard, too.
But the move was stymied for years by local zoning regulations - formerly, Swarthmore required that the repositioned garage could not be fewer than 10 feet from the property line. That was changed in 2012, allowing the Smythes to locate their workshop 3 feet from the property line.
As Holland tells it, several aspects of the original garage - including its taupe walls and carriage doors - were re-created in the new building.
"The doors are Dutch doors, with half being able to remain closed so their dogs can stay in the workshop and not run around the yard when they entertain," Holland says.
The interior of the workshop includes multiple shelves and adjustable work platforms, as well as storage places for tools. Adjustable reading lights were installed in the walls so Robert could work on projects from various angles.
One show-business veteran resides at the new workshop: "This is the head of a bear puppet from the theater that I keep," Robert says, hugging it.
(Some of the remaining valuable puppets are in storage. The others were sold when the theater closed.)
To give their yard a new look, the Smythes hired landscape designer Tom Borkowski, who created a garden in a series of steps, with a wall and a circular area for a barbecue pit.
"We now have a place for entertaining in the yard," Susan says. "There is a space for any number of people to sit on picnic chairs and on the wall."
Last summer, Robert hosted a puppet-theater gathering that saw about 20 participants congregating in the yard.
For Robert, the workshop reflects the latest part of his philosophy about houses, which, he says, is best expressed in an article he found in This Old House magazine: "I don't believe anyone owns a house, I think you are just preserving it for the next owner."
But also, the workshop represents what Robert calls Step 3 in the improvement of the house.
"Our first step, when we moved in with two small children, was scraping the walls and removing wallpaper and paint," he says. "Everything in the house was traditional beige and white."
These days, the large living room, into which light flows from 12-pane casement windows, is filled with colorful, comfortable furniture.
Its walls are a forest green, and nothing in the room seems to be traditional beige.
A few years later, Robert says, the next step was an addition: a kitchen eating area on the first floor and, on the second floor, an extra bedroom suite for their children.
Done with renovating, are they?
"We are never finished with an old house," Robert says of his home, which Holland thinks was built in the mid- 1940s. "Next is installing tiles to repair the fireplace, which was painted white by a previous owner."
To which he adds: "It took a long time, but anyone who renovates a house right after moving in is making a mistake."