Multigenerational living puts grandparents, grown children under one roof

Kate Mercer and Sara Gordon grew up a block apart in their eclectic Cabin John neighborhood. They celebrated birthdays together, had sleepovers at each other’s homes, and ice-skated together on the C&O Canal when it froze over. Their moms were in the same book club and sewing circle. Now, Mercer, 34, and Gordon, 35, are moving back to the houses that their moms still live in and own. But this time, the longtime friends are bringing their husbands and kids with them.