How we built Atrium House

This piece is the second in a series of construction diaries for projects from 2023–24. The first, on The Foundry, is here.

I. Pre-construction

Atrium House started with a phone call from M. Aldridge in March 2022. They’d been looking for a brownstone in Cobble Hill for two years and couldn’t find one that worked for their family. They’d just bought a 25-foot-wide lot, three doors down from the brownstones they’d been looking at, and wanted to know whether we could build something that felt continuous with the block but worked for the way they actually live.

The first thing we said was that the budget they’d earmarked was about 20% short of what we thought the project would actually cost. The second thing we said was that we could probably get the schedule from the 30 months they’d been told to expect down to about 22, given the team we had available. We didn’t take the project then. We took it three months later, after they’d revisited their financing and we’d come back with a feasibility memo.

II. Schematic + DD

The atrium — the move that the project is named for — emerged in week 6 of schematic. The site is north-south oriented, 25 feet wide, with neighbours on both sides. Bringing daylight into the middle of any plan that long is hard. We tried four schemes that pushed apertures to the perimeter; none of them got light all the way down to the ground floor.

The breakthrough was an evening sketch by Sara Chen. A 22-foot tall central void, a single rooflight, and the interior plan wraps around it. Every room ends up with at least two sources of natural light because of the way the atrium puts light at the centre rather than only at the perimeter. We presented it the next morning. The owners said yes that day.

III. Permits + early concerns

The DOB plan-check came back with two flags: an as-of-right setback question and a fire-egress query about the atrium. The atrium itself wasn’t the issue (it’s code-compliant); the issue was that our intended sprinkler layout assumed a code interpretation the inspector didn’t share. We worked through it via a code consultation in week 12.

What I’d do differently next time

We should have caught the sprinkler layout question earlier. Our pre-filing review missed it because the atrium is unusual enough that nobody on the team had seen the same condition before. Now we run any project with a multi-floor void past Carlos and the fire-engineer earlier in DD — before we get to permit.

IV. Field

Foundation was clean. The lot had been a parking pad for forty years; we expected (and found) some petroleum contamination near the alley side. Remediation added two weeks but no money — we’d budgeted for it. Framing was on schedule. The atrium structure was the hard part: the rooflight had to land on a steel ring beam, and that beam had to take the lateral load on both upper floors. Riverside Steel delivered five days late. We absorbed the slip.

The brick blend took two rounds at the supplier to get right. The first batch read too pink against the neighbours; we sent the masons back to the yard with a sample of the existing block and a 6-blend pull. Round two matched. We held the project four days for the right brick. Worth it.

V. Finishes

The reclaimed oak for the stairs and millwork came from a barn in Lancaster County, PA, that we’d had a lot reserved at since DD. The shop drew the stair early so we could pre-fabricate as much as possible — the atrium meant the stair was one of the first big pieces in, and we couldn’t go back and replace it without scaffolding the whole atrium again. We pre-built it in the studio mill shop and trucked it in three pieces.

VI. Handover

Final inspection was clean. The DOB inspector spent two hours and signed off the same morning. CofO came two weeks later. We were two weeks under our committed schedule and 4% under our contracted budget. M. Aldridge moved in the following weekend.

VII. The 12-month walk

Wrote this essay the day after our 12-month walk-through. There’s a hairline plaster crack at the second-floor stair landing that we’ll fix next week, and one cabinet door rubs against the frame in summer humidity. That’s the snag list. The building is settling well. The owners are happy.

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