So far this year, Michael Hogan has spent more than $5,000 on metal bar stools, a curved sofa and other modern décor to furnish a newly built home he’ll never live in. That is because the dwelling is so small it is better suited for a resident the size of a mouse.

Hogan is among a new cohort of dollhouse devotees who are shaking up how grown-ups indulge in the classic children’s hobby. Instead of outfitting old-timey homes with old-timey décor, they are assembling contemporary miniature abodes packed with tiny versions of trendy trappings sold in stores such as IKEA and West Elm.