Orange County, North Carolina

Alternately called “The Trapezoid House,” Cassilhaus comprises three trapezoidal volumes across a very steep and densely forested site with views of Duke University Forest and New Hope Creek. The design of the house followed a rigorous program-driven architectural process with an unusual thesis—beyond their basic living requirements, the art and design loving owners wanted to host an artist residency and art gallery on site.

Design concept and solution:
The three central program elements for the project were two independent living areas—a 3,000-square-foot main house and a completely self-contained 1,000-square-foot guest house/artist studio—as well as dedicated gallery and storage spaces to house an extensive photography collection.

Two living “pods”—a multi-level main house and a self-contained guest house programmed for month-long visiting artist residencies—are joined by a long bridging structure housing the photography gallery and master suite, all of which is encircled by a clerestory. The clerestory maximizes reflected light without allowing direct sunlight on the photography collection, and gives the appearance of floating roofs. The metal roof over the bridge, lowered at the main pod, brings southern light via a second clerestory into the owner’s living area to the north. The seamless integration of the main volumes affords visiting artists the ability to control their level of privacy from total isolation to intimate connection as well as enjoy common use of gallery, library, and laundry spaces.

Outdoor spaces are a major focus, incorporating a south-facing roof terrace with outdoor shower, screened porch, multiple decks, and an at-grade terrace. Views to the forest and stream are to the north. The site’s steep slope allowed for a walk-in basement level for art storage, utility, and mechanical spaces. A carport and stone landscape retaining walls built from site-excavated stone complete the program.

Total construction cost:


Frank Konhaus and Ellen Cassilly

Ellen Cassilly Architect, Inc.
600 Foster Street
Durham, NC 27701
919.530.1149 P
919.949.9080 M
919.530.1718 F

Personnel in architect's firm who should receive special credit:
Ellen Cassilly, AIA, LEED AP Principal in Charge and lead design architect
Anna Wirth, AIA, Project Architect

Excel Engineering
Rob Munach, PE

Landscape Architect:
David Swanson Landscape Architect, PLLC
David Swanson, RLA  ASLA

Lighting Design: 
Jeffrey L. Brown, IALD, IES

Kitchen Design:  
The Kitchen Specialist
Mary Liebhold, CKD

Building Performance Consultant:                       
Enivronmental Quality Control
Jeff Reilich

Audio/Video and Security Consultant:
KONTEK Systems, Inc.
Frank Konhaus, CTS

General contractor
L. E. Meyers Builders
Myron Weiler, Construction Supervisor

James West  JWest Productions
Photo © James West JWest Productions

Frank Konhaus
Photo © Frank Konhaus

CAD system, project management, or other software used:
Google SketchUp



Structural system
Steel framework, 2x6 and 2x8 wood stud system, open web wood trusses

Structural Steel by Custom Steel

Exterior cladding
Concrete: Tri-City Contractors

Wood: Western Red Cedar

EIFS, ACM, or other
STO stucco

Installed by Reynolds Construction

Metal: Galvalume standing seam metal roof
Sheffield Metals (US Steel)

TPO Roofing

Installed by Pickard Roofing

Wood: Aluminium clad wood windows by Pella

Entrances: Pella

Sliding doors: Exterior Pella

Locksets and door hardware:

Interior Pocket Doors: Johnson Hardware

Custom Stair Rails:
Marc Maiorana/Iron Design Company

Wood Stove:

Grommets: Doug Mockett

Door stops:

Interior Tree Grates:
Neenah Foundry

Cabinet hardware:

Murphy Bed System:
Wall Bed Systems

Interior finishes
Cabinetwork and custom woodwork:
Unique concepts



Custom cedar ceiling
L. E. Meyers

Paints and stains:
Sherwin Williams

Installed by Hansell Painting

Plastic laminate:

Kitchen backsplashes: Eco-gres by Coverings etc.

Entry hall and lower bath: Rex Ceramiche  Meteaux Roulle Rouge

Master bathroom: Tau Ceramica Corten A.

Guest bathroom: Portobello Galleria D'arte Domenico Verde

Granite countertops:  Prescott Stone Fabricators

Pre fabricated Corian shower bases:
Kramer Fabrications

Resilient flooring:
Basement: Expanko XCR4

Carpet: Bolyu

Wood flooring: Custom Quarter Sawn Cherry and Ash
Select Forest Products

Chairs:  Dining chairs by Wilkhahn
Living room Eames chair by Herman Miller
Living room Breuer Wassily Chair by Knoll

Library chairs by IKEA

Tables: Custom Breakfast Table by Seth Rolland (Port Townsend, WA)
MO Kumi dining table

Library coffee table custom designed and built by Ellen Cassilly Architect

Deck table by Butch Anthony

Other furniture:
Living room couch: Montis

Vintage George Nelson Platform Bench by Herman Miller

Dresser by Blu Dot

Living room coffee table by Naos

Master bedroom set by: Lago
Interior ambient lighting:
Low voltage track lighting by Tech Lighting

Dining Pendant:  Foscarini

Kitchen and Living Room Pendants: Louis Poulsen

Artist Studio Pendant:  Itre

Artist Studio Sconce:  Fontana Arte

Library Pendant:  Flaver

Master Bath Ceiling Fixture:  Ron Rezek for Artemide

Master Bedroom and Living Room Uplights:         Visa

Master Bedroom Table Lamps:  Foscarini

Ceiling utility lighting:

Exterior: Kim LED wall sconces

Controls: Lutron lighting controls and dimmers

Master tub by Agape

Master sinks by Lacava

Dual Flush Toilets by Toto

Kitchen sinks by Franke

Faucets by Grohe, Danze, Jado, and Hansgrohe

Lower bathroom sink by Kohler

Outdoor Shower by Pool Shower

Solar Hot Water System by Southern Energy Management

Rainwater Collection Cistern by Green Horizon