Sponsors:

Jay Orr, AIA, LEED® APARQ Architects

Phone: 410.235.1043 Email: ay@arqarchitects.com Website: www.arqarchitects.com

HONORABLE MENTION MOST COST-EFFECTIVE DESIGN

50'-0"

15'-0"

PROJECT CONCEPTB155

001 / 008 002 / 008

SCALE: Not To Scale

Rowhouse Revisited!re-imagining the Baltimore rowhouse for greater economy, higher efficiency and reduced environmental impactRowhouses in Baltimore, as in many east coast American cities, are the primary building blocks of the urban residential landscape. Codified as a distinct building type in the 19th century, the rowhouse continues to provide an opportunity for single-family homeownership at a density that supports city living and culture. The adaptability and availability of traditional rowhouses ensures that the existing stock of houses willl remain attractive options for renovation and reuse. However attractive traditional rowhouses are for rehabillitation and reuse, they do not present an ideal paradigm for new construction. Due to a lack of thermal insulation and viable air barriers, older rowhouses are energy intensive to operate and less comfortable during peak heating and cooling seasons. Solid masonry construction also makes them difficult to retrofit. The traditional materials, brick in particular, that make historic homes so beautiful also make them labor and energy intensive, as well as costly, to build. Finally, the conventional subdivision of interior spaces does not always readily support changing lifestyles and the patterns of use associated with contemporary urban living. This design proposes a model for maintaining the positive urban attributes of the traditional rowhouse, while providing an updated platform that can support modern patterns of use within the broader context of our current cultural and environmental reality. By building new rowhouses less expensively, using contemporary materials and construction practices, the project looks to reinvigorate this traditonal typology. If the contemporary rowhouse can be made even more energy efficient and less costly to own and operate, with proportional reductions in the lifecycle costs associated with its materials and methods of construction, these buildings can continue to provide a vision for urban living that is as compelling in the 21st century as it was in the 19th.

above: image of rowhouses in the 1500 block of Broadway from the APA Carbon Challenge submission materials

MINIMIZE THE FOOTPRINT Restricting the footprint of the rowhouse to the minimum dimensions permitted by code and the terms of the competition reduce the environmental impacts associated with the foundation and insulation. A crawlspace instead of a slab-on-grade reduces the use of concrete.

STACK THE FLOORS Locating the living spaces on the first floor allows separation from the three bedrooms on the second and third. Having three floors also gives more definition to the space of the street.

bedroom 3bedrooms 1 and 2living spaces

350 sf

650 sf

750 sf

SIMPLIFY THE MASSING The stacked, stepped massing above creates large exterior exposures and complicacted air-sealing and insulating details. Sloping the line of the roof minimizes exterior exposures and detailing while creating more dynamic interior spaces.

COMBINE THE STAIRS !AND HALLWAYS Combining the vertical and horizontal circulation in one space minimizes the need for interior partition walls while maximizing the usable living space for the residents.

USE ADVANCED WALL!AND FLOOR FRAMING The vertical party wall and horizontal floors joists align at 24" o.c. allowing for greater efficiency in framing and reductions in material use.

USE ADVANCED WALL!AND ROOF FRAMING The vertical exterior double-stud walls and horizontal roof rafters align at 24" o.c. allowing for greater efficiency in framing and reductions in material use. Longer roof spans require deeper TJIs leaving more space for cavity insulation.

SIZE WINDOWS FOR!EFFICIENCY The majority of the windows on the project are fixed and sized to fit within the 24" structural bays of the framing. Larger openings with operable windows occur only where desirable for ventilation or required for egress.

the sloped roof allows more light to the back yard while channeling roof runoff to the permeable surfaces to be abosorbed on site

the three-story facades offer definition to the

street edge and continuity with the historic rowhouses

the individual carports are not included in the base project

and would require variances to allow the single space to meet

the on-site parking requirements and exceed the 65% limitation

on impermeable surfaces

end-of-row units have additional opportunities for openings and bay

windows

1

2

3

4

5

6

7

BUILDING DRAWINGSB155

003 / 008 004 / 008

SECOND FLOOR elev +11'-0" / +13'-0"

FIRST FLOOR elev +2'-0"

THIRD FLOOR elev +24'-0"

ALLEY ELEVATION mid-block unit

STREET ELEVATION mid-block unit

SCALE: 1/8" = 1'-0"

tubular daylighting unit

perforated, galvanized metal screen covers mini-split condenser

and vent pipes

osb (ripped into 2'-0" panel sections) used for accent wall surface and doors in stairway

operable windows provided for ventilation

and egress

fixed windows provide higher energy performance and are sized to fit winthin 2'-0" stud bays simpifying construction

end units can have additional windows and bays

PVC membrane roof with simulated ribs at 2'-0" o.c. to align with roof joists

insulated, conditioned and sealed crawl space allows area for piping runs and ducts

bedroom 3 ("garret")

bedroom 2 bedroom 1 ("loft")

full bathroom

half bathroom

living room dining roomkitchen

condesning clothes washer

work area

recycled rubber flooring

engineered hardwood finished flooring

wood rainscreen cladding system

BUIL

DING

SEC

TIO

N

BUILDING SECTION

BUIL

DING

SEC

TIO

N

FIRST FLOORFIRST FLOOR

SECOND FLOORSECOND FLOOR

THIRD FLOORTHIRD FLOOR

exterior window isometric not to scale

bent, galvanized, perforated metal sun screens with configrations based on

building orientation

west-facing elevation

south-facing elevation

inset wood panel flush with window frame provides support for the sun screen

erv and water heater

B155

005 / 008 006 / 008

PATIO + GARDEN optional build-out

CAR PORT optional build-out

ROWHOUSE primary project

ALLEYSTREET

roof water cistern

permeable paver patio with sub- surface storage

rain barrel (garage roof)

permeable stone trench with sub- surface storage

optional PV array

optional PV array or solar thermal panels

permeable gravel subsurface water

storage with underground injection chanber (UIC)

to capture runoff from street

street tree planters with continuous "root tunnels" and subsurface irrigation

SITE DRAWINGSSCALE: 1/8" = 1'-0"

AREA PLAN: 1" = 60'-0"

site plan includes nine (9) rowhouses total with the illustrated interior block unit shown hatched

SITE PLAN

SITE SECTION

future rowhouse build-out across North Bethel Street

N BE

THEL

STR

EET

one way alley traffic

vehic

le tu

rn-in

/ b

ack-

out

SITE SECTIONSITE SECTION

R-60

R-48

R-24

IRC 2012

IRC

2012

CONSTRUCTION DRAWINGSB155

007 / 008 008 / 008

SCALE: 1/4" = 1'-0"

EAST-WEST SECTIONNORTH - SOUTH CROSS-SECTION 1

NORTH - SOUTH CROSS-SECTION 2

mini-split condensing unit located on platform

operable skylight promotes passive ventilation

erv circulates fresh air while recovering

energy from exhaust air stream

mini-split indoor unit 1 condtions air

for upper floors (bed rooms)

mini-split indoor unit 2 (located

in conditioned crawlspace)

conditions air for first floor

osb panels used for interior accent walls

as well as sliding closet doors

erv distribution vent

mini-split return grill

FRAMING +!FOUNDATION

INSULATION +!AIR-SEALING

CLADDING +!ENVELOPE1 2 3

The project employs advanced framing techniques with joists and rafters aligned with studs at 24" o.c. to minimize the lumber required for framing. Floors consist of 5/8" high-strength OSB over engineered TJI joists. The superstructure rests on a poured concrete foundation wall and continuous footings. While the concrete foundation at the front and back walls with exterior exposures extends 8"above grade, the party walls bear directly on low foundation walls to minimize the use of concrete. Raising the first floor above an insulated, conditioned crawlspace likewise reduces the use of concrete (compared to slab-on-grade construction) while providing conditioned space for mechanical equipment, pipes and air distribution ducts.

This rowhouse design minimizes the energy required to heat, cool and condition the building by using a range of insulating and air-sealing strategies to reduce air infiltration and envelope loads. Double-stud walls at the front and rear exposures provide 12" depth for blown cellulose insulation. With the addition of 2" of continuous insulation at the face of the walls, the project shoud achieve in excess of R-40. TJI rafters that support the roof deck also provide deep, 16" cavities for blown or dense-packed cellulose with 2" of continuous insulation above the decking to achieve insulating values in excess of R-50. The simplified building massing with few exterior corners, combined with windows fit to the 24" o.c. exterior roof and wall framing dimensions, help to simplify the air-sealing of the exterior sheathing, reducing the number and complexity of critical junctures needing attention.

To help further reduce the quantity of material required to construct the rowhouses, the envelope and massing have been reduced to a simple form that encloses a maximum of interior space with minimal exterior exposures. The street facade of the building is clad with horizontal 1x square-edged wood boards in a rainscreen system with 1/4" gaps. The boards would be fastened to vertical 1x furring strips painted black to blend with the unmarked water-resistive layer that overlays the continuous board insulation and building sheathing. The roof cladding consist of a PVC membrane with simulated standing seams that align with the underlying rafters. The membrane continues on to the vertical surface of the rear exterior wall to provide a continuous cladding system that extends from the peak of the front elevation to the base of the rear exterior wall. This gradual, sloping transition from front to back and from roof to wall minimizes roof to wall transitions that can become points of water infiltration and challenges to insulate and airseal.

NORT

H - S

OUT

H CR

OSS

-SEC

TIO

N 1

NORT

H - S

OUT

H CR

OSS

-SEC

TIO

N 1

NORT

H - S

OUT

H CR

OSS

-SEC

TIO

N 2

NORT

H - S

OUT

H CR

OSS

-SEC

TIO

N 2

Per IRC 2012, section R302.2 exception 1, the rowhouses are permitted to use a single frame for the party wall if the assembly is 1-hour rated from both sides and continuous to the underside of the roof decking and to the front and rear exterior walls. The rowhouses are also provided with NFPA 13- compliant sprinkler systems required by the IRC.

The street facing exterior walls consist of double-stud frames with blown cellulose in the cavity and continuous rigid polyisocyanurate. The exterior cladding is a wood rainscreen.

Per IRC 2012, section R302.2.2.1 exception, the design includes a minimum class C roof covering with 5/8" type X gysum board installed directly below the roof sheathing on nominal 2" ledgers for a distance of 4'-0" from the common walls (and no roof penetrations within these 4'-0" zones), so no parapet is required between the units.

The exterior roof surfaces consist of PVC membranes with simulated standing seams over polyisocyanurate insulation and decking on TJI joists. The cavities are filled with blown and dense-packed cellulose insulation.

The ground level consists of wood flooring over a sealed, conditoned crawlspace. Rigid extruded polstyrene insulation topped with sheets of cementitious backer board allow access to the space without requiring a full concete slab.