East Lake Forest was built up through the estate era, roughly 1890 to 1930, and the houses were planned around a working household. The kitchen sits at the far end of the plan, reached through a butler’s pantry and usually a service corridor, with a back stair, a larder, a laundry and sometimes a staff sitting room grouped around it. West of the tollway the stock is newer, 1960s to 1980s, and behaves like a conventional suburb.
In an estate-era house the raw floor area is not the problem. That service zone is often larger than a modern kitchen and family room together. It is simply divided into six small rooms by walls built to keep the work of the house out of sight and out of earshot.
Combining them is a structural project with a long tail of services. Some dividing walls are partitions; the wall separating the zone from the dining room almost always carries the floor above. And because the kitchen is at the end of the house, the runs back to the stack, the water main and the panel are long — which is the real reason a Lake Forest kitchen costs more than the same kitchen in Wilmette.