A stepping stone for seven

Seven people who graduated together could each sign separate leases in Somerville and spend $1,300 a month per room, or they could buy the building.

At 20% down split seven ways, each person puts in $34,000. Add 3% closing costs divided equally and total cash invested per person is $39,100. Monthly all-in costs for the building come to $8,117: a $6,017 mortgage on a $952,000 loan at 6.5%, plus $2,100 in operating expenses. Split seven ways, each person pays $1,160 a month. Comparable rooms in Somerville rent for $1,300 today. Before anything appreciates and before the mortgage balance moves a dollar, co-buying saves each person $140 a month.

The two-family layout gives the group two full kitchens and natural separation within the building, without creating any distinction in ownership or financial obligation. All seven are residents. All seven hold an equal stake. Nobody is a landlord and nobody is a subletter. Three off-street parking spots and a two-minute walk to the Gilman Square GLX makes this property commuting-friendly without needing to be in the most expensive part of the city.

The building functions like any other shared household, except that the monthly costs are below what each person would pay renting alone, and every payment builds equity rather than disappearing into a landlord's balance sheet.

Before purchasing, the group put one rule into their co-ownership agreement: at year 5, they sell the property unless there is a unanimous vote to stay.

By year 5, at 4% annual appreciation, the property is worth $1,447,800. The mortgage balance has dropped to $891,200. Total equity in the building is $556,600.

In this scenario, they vote to hold for another 3 years.

Two of the seven have gotten married and are searching for their own homes. Neither wants to force a sale while they house-hunt, and neither wants to give up an equity position that has nearly doubled their initial investment in five years. The structure lets them stay in without staying in the building.

Both rent their spots to people chosen by the five residents still living there. Monthly rent is $1,400. By year 5, comparable rooms in Somerville are going for $1,435 a month, so the incoming renters pay slightly below market. The five residents get neighbors they've vetted through their own network. The renters get a below-market room in a building where the people living there actually chose them. The group finds them through existing social connections, because the kind of people who buy a building together after college tend to know other people worth living with.

The five who stayed pay $1,160 a month, same as they always have. The renters' payments go directly to the two absentee owners, not into any shared pool. The building's ownership structure doesn't change. All seven still hold their equal shares, and the mortgage keeps getting paid down.

At year 8, all seven vote to sell. At 4% annual appreciation from the $1,190,000 purchase price, the property is now worth $1,628,600. After a 3% sale cost and the $844,100 remaining mortgage balance, the group distributes $735,600. Each person's share is $105,100.

For the two who moved out at year 5, that $105,100 is a down payment. That's what the bylaws were designed to produce: a defined exit, at a moment when the proceeds are large enough to fund the next step. They spent five years living in the building, three years collecting $240 a month on top of building equity, and walked out with more than enough to buy their next home with a substantial down payment.

For the five who stayed all eight years: gross payments over 96 months totaled $111,360, plus $39,100 in initial cash, for $150,460 out. They received $105,100 at sale. Net housing cost over eight years: $45,360, or $472 a month effective. Someone renting in Somerville for the same period, starting at $1,300 a room and increasing 2% a year, would have paid roughly $134,000 with nothing at the end.

Renting assumes $1,300/room at purchase, growing 2% annually. Co-buying assumes 4% annual appreciation, 6.5% 30-year fixed mortgage. Not financial advice.