Commercial
& Residential Architecture

Based in Pittsburgh, we lead projects with clarity, coordination, and consistent communication.

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What we do…

Commercial
spaces

Interior fit-outs / renovations

New construction

Retail, healthcare, mixed-use, workspace, industrial & higher education

Residential
Design

Individually designed custom homes

Home additions

Design & technical packs for developers

Quality control services

Quality control peer reviews of documents

Code & compliance audits

Cross-discipline coordination review

Coffee shop counter with a blue wall on the left, barista equipment, menus, and pendant lights.

Medical examination room with a dental chair, a chair in the corner, a window showing trees and parked cars, a wall-mounted TV, and a sink with a chair nearby.

Office workspace seen through glass wall, with computer monitors, a desk, chairs, and decorative items including candles, framed photos, and plants.

A sterile hospital room with gray cabinetry, a sink, a soap dispenser, a window, and a padded examination table.

A modern MRI machine in a medical facility with colorful ambient lighting in purple, red, green, and blue hues.

A modern office lobby with seating area, front desk, computer monitors, and a television on the wall, featuring wood and white decor with blue accent lighting.

Modern office lounge or break room with round tables, black and beige chairs, a blue textured accent wall, and large windows letting in natural light.

Who we work with…

We keep projects moving with clear communication, coordinated teams, and documentation that’s easy to understand and build from. Our team stays involved from early planning through construction, so decisions don’t stall and projects stay on track.

Icon image of a real estate sale sign in white

commercial real estate

Icon image of high rise buildings in white

property OWNers

contractors

homeowners

Learn more

Our work…

Backyard of a house with green grass, a concrete patio, patio furniture, a grill, and an air conditioning unit, with a blue sky and scattered clouds overhead.

A living room with a vaulted ceiling, wooden beams, and a skylight. There is a brick fireplace with a flat-screen TV mounted above it. The room has two white armchairs facing the fireplace, a tan leather sofa, and a dark sofa. A chandelier hangs from

A modern duplex home with two attached garages, white siding, black trim, and dark gray roofs, surrounded by green trees and a sidewalk in front.

Living room with high vaulted wooden ceiling, large windows, beige sofas with blue and beige cushions, a wooden coffee table, a stone fireplace with a mounted TV, and a beige rug on hardwood floors.

Modern white house with a gray roof, large front porch, and landscaped yard under a blue sky with clouds.

A modern two-story house with a blue exterior, black roof, and a stone chimney, surrounded by trees and a lawn, featuring a driveway and a covered porch.

A 3D floor plan of an apartment with multiple bedrooms, bathrooms, kitchen, and living areas in a monochrome color scheme.

Meet
Katelyn Rossier…

I’m Katelyn Rossier, Principal Architect and Founder of Rossier Architecture & Design.

I founded the firm to create thoughtful, practical spaces that support everyday life. With experience across healthcare, commercial, workplace, and residential projects, I focus on building strong client relationships and guiding projects with clarity, collaboration, and care.

Picture of Katelyn holding a hard hat and a roll of drawings

As Architects, We’ll be the advocate and protector of your investment.

Let's talk

Kind words…

“Katelyn’s attention to detail is remarkable.

Our general contractor and several others involved in the construction process consistently commented on the thoroughness and clarity of her plans, which contributed significantly to an efficient and well-coordinated build.”
Seth
“Katelyn visited my house with short notice and took her time with the site visit.
She was helpful to provide suggestions, one being to locate the 2nd bathroom in a location that made more sense. The additional space has added comfort for my family and friends.”
Glenn
“Beyond her technical expertise, Katelyn brought professionalism, organization, and a calm, solutions-oriented approach that made the entire experience seamless.
We are thrilled with the result and deeply appreciate the level of care and precision she brought to every stage of the project.”
Lauren
Katelyn, has great abilities, first is her listening, during the meetings of staff and patients to design a patient and staff friendly building with all the constraints of the site. Her attention to detail was excellent. She can apply her architecture knowledge and skills in a very understandable manner and often bringing up points for the members of the committee to consider which an excellent quality.
Don

Commercial& Residential Architecture