We plan to turn our garage into a home office and a painting studio. The garage is currently a 30 foot x 18 foot by 12.3 foot structure, comprised mostly of old, pre-war lumber. The building rests on a concrete perimeter foundation, has a dirt floor, and is clad in old cedar planks. The interior is unfinished. Currently, the structure has access to electricity and water.

Pictured here are the various additions we wish to make within this building. Highlights include a vaulted ceiling, a restroom, lighting and outlets, hot water, and increased wall and rafter-bay thickness to accomodate proper insulation. Wall insulation will comprise of mineral wool, while the ceiling flash-and-batt insulation will be comprised of closed-cell foam and mineral wool (the roof will be a "hot roof" with no venting). The studio/office will have a 6" concrete slab as a base for further interior work.

Current framing consists of a combination of pre-war lumber (of actual size). The studs are either 2x4s or 4x4s. Due to rot, a good deal of the old studs have been cut off at the bottom, or replaced with newer members. With the newer members, the new wall thickness is 5.5". Bottom plates consist of new 2x6 pressure-treated boards while the top plates consist of 2x4 pre-war lumber.

Rafters are made of old 2x4 lumber placed at 24" O.C.. Rafter ties and webbing comprise of 1x6 material. There is currently no ridge board.

The roof on the western side of the garage is partially clad with old roof decking (one inch thick), while the eastern roof is clad with plywood and no old boards. In this eastern section, the rafters are 1 inch higher in elevation, to adjust for the lack of 1 inch legacy decking. Newer plywood decking is applied to the entire roof span.

Shear panels will be placed at the corners, and will comprise of 15/32" APA Structural 1 plywood, nailed at 3" on edge and 6" in field. Shear walls are fastened to foundation using Simpson HDU2 holdowns, anchored with Simpson epoxy bolt system. The structure is within Seismic Design Category E, on soil type D, SDS 1.096, with max wind load of 110mph (Exposure Category C). See CDC 2308.6.1.

NOTE that the top plates are 2x4 actual sizes while the studs are 5.5" in thickness. Ledger boards at the top plates will be attached to the top plates prior to shear panel installation.

ALSO NOTE that the shear wall plywood will be installed AFTER any essential mechanical (wiring) within those walls are installed, and after insulation & vapor barriers have been installed in those areas. Essentially, this means that some panels will be wired and insulated before room framing occurs.

The current walls have new 2x6 studs, but the top plates remain either 4" (actual) or 3.5" in width. There is a gap at the top of the walls that need to be accounted for, when we install the shear panels and/or hurricane ties. This illustration elucidates how we will cut and attach these ledger boards to provide an attachment surface at the top plates.

The eastern portion of the building will boast a vaulted ceiling.

All legacy rafters will be sistered with new 2x10 members. The new rafters will be secured by LRUZ26 hurricane ties that are mounted on new ledger boards at the top plates. The new 2x6 rafter ties will be installed 48" apart (every other rafter), placed vertically at the first third of roof height. Gussets will be installed at the ridge, in lieu of collar ties.

The western portion of the building will not have rafter ties. In place of rafter ties, we will install 2x10 ceiling joists joined by Simpson TP57 plates. Along with resisting outward thrust, the joists will serve as the ceiling for the interior rooms and act as floor joists for the storage loft. The butt joints of the joists will rest on top plates of the interior room framing.

The mechanical room and bathroom will be framed under 2x10 ceiling joists (joined by Simpson TP57 plates). The ceiling joists in the center will bear some lateral load (acting as rafter ties), and will also serve as framing for a small storage loft.

In this visualization, you will note the existence of plumbing/mechanical walls and some framing to serve drywall installation and aid in the routing of mechanical lines.

Above the loft platform there are what looks to be a purlin/strut system, but this framing is there to serve as drywall support.

Electric will be fed from the panel in the mechanical room. Note that several 'plumbing walls' will be installed to make room for plumbing pipes and wires. We will use the rafter bays to run most of the mechanical.

Pressurized water will be distributed via PEX lines, branching from small manifolds. Hot water will be heated by a small tankless heater in the mechanical room.

Waste will eventually run to a Liberty lift station, which will grind and pressurize the waste destined for the main house.

Toilet waste pipes will be 3" diameter. Shower waste pipes will be 2" diameter. Sink waste pipes and vent stack will be 1.5" diameter. All three fixtures will vent to the same vent stack.

Note the use of plumbing/mechanical walls. These walls will make it easier to run pipes and other mechanical lines inside the building, while avoiding shear walls.

Waste will eventually run to a Liberty lift station (Liberty PRO370), which will grind and pressurize the waste destined for the main house. The Pro370XL will be capped by a Liberty access riser (AR18), which will allow us to sink the unit to a maximum of 18" below grade