Architect and contractor Andrew James Gregor on the sidewalk in Berkeley, California, in front of his current remodeling project. The clients had the choice of building out into the back lot or building a new second story on the house. “We opted to build upwards,” says Gregor.
Tarps in place over the existing bungalow and its new second story, with framing in progress under the tarps. Gregor’s crew opened up the roof just as the weather began to turn rainy, and had to rush to protect the structure as a fierce Pacific storm was approaching with high winds and heavy rain. “For California, it was the ‘storm of the century,’” says Gregor. “A few lawn chairs blew over.”
A view of the back lot behind the bungalow, cluttered now because of the construction. Gregor opted to preserve the outdoor living space behind the house. In California’s mild Mediterranean climate, fenced and landscaped outdoor spaces commonly serve as another room in the dwelling.
Gregor looks at a space he and his crew used to gain access to the home’s existing foundation and first floor frame, which required extensive reinforcing to get into compliance with California’s stringent seismic requirements. Fortunately, the existing framing had not suffered much deterioration, says Gregor — unlike many other similar structures in the area.
A view of the crawlspace beneath the dwelling, showing a little of the new structure Gregor and his crew created. The project included two new strip footings about two feet deep and two feet wide running across the width of the house to support shearwalls, as well as 32-inch-deep piers for new posts that ran up through the first story to support the second floor beam system and the roof.
This is one of two shearwalls running across the width of the house. Gregor was able to achieve the strength he needed by doubling up the studs in the existing partition walls, and installing hold-downs connected to the new strip footings installed beneath the walls.
Gregor points out a hold-down at the top of the newly reinforced shearwall, which ties the wall to another shearwall above it, to maintain a continuous load path to manage seismic forces.
Gregor pulls back insulation in the outside wall to reveal another hold-down, part of the beefed-up structure for the long front-to-back exterior walls of the bungalow.
A look at the interface between the old first-floor ceiling of the house (originally the home’s only ceiling) and the newly built second floor structure. The old ceiling’s frame and finish were left mostly intact during the remodel, allowing the homeowners, a young family, to stay in place during construction. Supported by an independent post and beam skeleton, the new second floor is structurally independent of the old ceiling, which remains held up by the home’s original walls as it always has been.
Shown here is the wood I-joist ceiling of the new second floor, with a temporary pitched roof structure installed above it to hold the tarps that Gregor and his crew had to install on an emergency basis as a Pacific storm approached. The temporary 2x rafters and wood I-joist ridge at the top were removed when dry weather returned. The horizontal wood I-joists at the bottom of the frame remained as ceiling and roof structure. The ceiling I-joists were packed up with 2x10s ripped on a taper from 10 to about 3 inches (shown in the coming images), to create a low-slope roof deck which Gregor topped with a waterproof membrane.
A view of the newly framed second story walls, after the temporary tarp roof was removed. The yellow poly in the foreground shows where a walkable outdoor deck will be, accessible from the second floor living space, overlooking the back yard.
A view from below of the built-up ceiling and roof structure for the second story addition. The wood I-joist ceiling structure, viewed earlier, remains in place, with 2x framing on top of it cut to create the slope of the low-pitched roof. The joists are tied into a central girder on top of a bearing wall, using steel joist hangers.
A view from above the roof of the roof and ceiling structure, showing the wood I-joists and their ripped 2x build-up.
The framed and sheathed roof and parapet, with a fillet applied to the roof/parapet joint (right) in preparation for roll roofing.
Roofing contractor Martin Toledo installs the base layer of underlayment (left), then proceeds to install a torch-down roofing membrane (right).