We Are Open

Open Architecture Office

Open Architecture Office

Chicago IL

Open Architecture Office

Chicago IL

Architecture

Architecture

Urban Design

Urban Design

Research and Development

Research and Development

Fabrication

Fabrication

Laser Scanning

Laser Scanning

Advanced Visualization

Advanced Visualization

OAO designs residential, mixed-use, and civic architecture that remains clear, buildable, and resilient from concept through construction. We balance design ambition with real-world constraints, helping clients move forward with confidence at every scale.

Testimonials

Testimonials

Client
Experiences.

/66

Our team brings experience from more than 66 completed projects, informing how we design, coordinate, and deliver work today.

Peter Koopman

Director of Development - Quarterra Midwest

“Mariusz was an absolute pleasure to work with. He went above and beyond to ensure our project design was outstanding while balancing budget and hitting every deadline.”

Peter Koopman

Director of Development - Quarterra Midwest

“Mariusz was an absolute pleasure to work with. He went above and beyond to ensure our project design was outstanding while balancing budget and hitting every deadline.”

Peter Koopman

Director of Development - Quarterra Midwest

“Mariusz was an absolute pleasure to work with. He went above and beyond to ensure our project design was outstanding while balancing budget and hitting every deadline.”

Melanie Jefferies, PMP, DASM

COO of Production & Delivery - Milhouse

Mariusz Klemens is an exceptional architect and trusted partner whose work consistently balances design excellence, technical rigor, and real-world constructability. He brings a thoughtful and disciplined approach to architecture, one that is deeply collaborative and grounded in a clear understanding of how projects are planned, designed, and delivered. Mariusz is equally effective working with owners, developers, engineers, and contractors, ensuring alignment across teams and proactively minimizing risk throughout the project lifecycle. I would highly recommend Mariusz Klemens and OAO to any organization seeking an architect who combines strong design vision, technical expertise, and a true commitment to partnership.

Melanie Jefferies, PMP, DASM

COO of Production & Delivery - Milhouse

Mariusz Klemens is an exceptional architect and trusted partner whose work consistently balances design excellence, technical rigor, and real-world constructability. He brings a thoughtful and disciplined approach to architecture, one that is deeply collaborative and grounded in a clear understanding of how projects are planned, designed, and delivered. Mariusz is equally effective working with owners, developers, engineers, and contractors, ensuring alignment across teams and proactively minimizing risk throughout the project lifecycle. I would highly recommend Mariusz Klemens and OAO to any organization seeking an architect who combines strong design vision, technical expertise, and a true commitment to partnership.

Melanie Jefferies, PMP, DASM

COO of Production & Delivery - Milhouse

Mariusz Klemens is an exceptional architect and trusted partner whose work consistently balances design excellence, technical rigor, and real-world constructability. He brings a thoughtful and disciplined approach to architecture, one that is deeply collaborative and grounded in a clear understanding of how projects are planned, designed, and delivered. Mariusz is equally effective working with owners, developers, engineers, and contractors, ensuring alignment across teams and proactively minimizing risk throughout the project lifecycle. I would highly recommend Mariusz Klemens and OAO to any organization seeking an architect who combines strong design vision, technical expertise, and a true commitment to partnership.

Jonathan W. McCulloch

Chief Executive Officer -Belgravia Group

Mariusz is one of the most talented, multi-disciplinary architects I’ve worked with. His ability to balance creativity, pragmatism, and project management makes him a rare find. He does all of this while embracing and implementing the latest technologies to enhance design, presentation, and outcomes.

Jonathan W. McCulloch

Chief Executive Officer -Belgravia Group

Mariusz is one of the most talented, multi-disciplinary architects I’ve worked with. His ability to balance creativity, pragmatism, and project management makes him a rare find. He does all of this while embracing and implementing the latest technologies to enhance design, presentation, and outcomes.

Jonathan W. McCulloch

Chief Executive Officer -Belgravia Group

Mariusz is one of the most talented, multi-disciplinary architects I’ve worked with. His ability to balance creativity, pragmatism, and project management makes him a rare find. He does all of this while embracing and implementing the latest technologies to enhance design, presentation, and outcomes.

(12)

Projects.

©2026

©2026

Our work focuses on residential, mixed-use, and civic architecture that supports daily life, strengthens neighborhoods, and remains viable through changing economic and urban conditions.

Each project reflects a disciplined approach to design, balancing ambition with feasibility and long-term performance.

(12)

Projects.

©2026

Our work focuses on residential, mixed-use, and civic architecture that supports daily life, strengthens neighborhoods, and remains viable through changing economic and urban conditions.

Each project reflects a disciplined approach to design, balancing ambition with feasibility and long-term performance.

Why choose us

Why choose us

We deliver thoughtful architecture that stands up to real-world constraints. Our work is design-led, informed by research, and rigorously developed so projects remain clear, resilient, and buildable from concept through construction.

We deliver thoughtful architecture that stands up to real-world constraints. Our work is design-led, informed by research, and rigorously developed so projects remain clear, resilient, and buildable from concept through construction.

Your digital journey begins with a conversation. Let's talk today.

Close-up portrait of a person wearing a gray insulated hooded jacket with the hood up, showing their face framed by the hood against a light background.

Your digital journey begins with a conversation. Let's talk today.

Close-up portrait of a person wearing a gray insulated hooded jacket with the hood up, showing their face framed by the hood against a light background.

We deliver rigorous, buildable architecture that performs over time, balancing design quality with real-world constraints.

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Projects delivered across prior practice

Our team brings deep experience across housing, mixed-use, cultural, and urban design projects.`

OAO is a focused practice built on extensive experience. Our team has delivered over 50 projects across housing, mixed-use, cultural, and urban design, shaping environments where people live, work, and connect.

0+

Projects delivered across prior practice

Our team brings deep experience across housing, mixed-use, cultural, and urban design projects.`

OAO is a focused practice built on extensive experience. Our team has delivered over 50 projects across housing, mixed-use, cultural, and urban design, shaping environments where people live, work, and connect.

0+

Projects delivered across prior practice

Our team brings deep experience across housing, mixed-use, cultural, and urban design projects.`

OAO is a focused practice built on extensive experience. Our team has delivered over 50 projects across housing, mixed-use, cultural, and urban design, shaping environments where people live, work, and connect.

0+

Awards

Collectively, our past work has been recognized with 12 design awards, including multiple AIA Honor Awards and international distinctions.

0+

Awards

Collectively, our past work has been recognized with 12 design awards, including multiple AIA Honor Awards and international distinctions.

0+

Awards

Collectively, our past work has been recognized with 12 design awards, including multiple AIA Honor Awards and international distinctions.

What we do

What we do

Services.

Services.

(4)

(4)

(4)

(001)

Architecture

We design residential, mixed-use, and civic architecture that balances clarity, feasibility, and long-term performance. Our work prioritizes livability, constructability, and durability, ensuring projects remain resilient from early concept through construction.

Categories

Residential

Mixed-Use

Civic

Architecture

(002)

Urban Design

Our urban design work focuses on neighborhood-scale systems, public space, and development frameworks that support housing, civic life, and long-term growth. We approach cities as interconnected environments shaped by daily use, infrastructure, and policy realities.

Categories

Neighborhood Planning

Mixed-Use Districts

Transit-Oriented Development

Parks and Open Space

Urban Design

(003)

Research and Development

Research and development at OAO supports clearer decisions and better outcomes. We use applied research to test assumptions, evaluate feasibility, and inform design strategies before risk is locked in.

Categories

Visioning and Strategy

Technology and Visualization

Sustainability and Performance

Publications and White Papers

Research and Development

(005)

Laser Scanning

Laser scanning is a core component of OAO’s research and development practice. It allows projects to begin with precise, real-world spatial data rather than assumptions or incomplete documentation. By capturing existing conditions accurately from the outset, laser scanning strengthens decision-making across planning, design, coordination, and delivery.

Categories

Existing Condition Scanning

LiDAR and Point Cloud

As-Built Documentation

360 Site Capture

Laser Scanning

(004)

Fabrication

Our fabrication experience informs how details are designed, coordinated, and built. This knowledge strengthens constructability and ensures architectural intent carries through to execution.

Categories

Physical Design Models

In-House Mockups

Detail Prototypes

Assembly and Constructability Studies

Fabrication

(006)

Advanced Visualization

Advanced visualization supports clearer decision-making across design, coordination, and delivery. These tools help clients, consultants, and communities understand projects accurately before construction, reducing risk and improving alignment.

Categories

Virtual Reality

Design Visualization

Construction Coordination

Aerial and Site Analysis

Advanced Visualization

(001)

Architecture

We design residential, mixed-use, and civic architecture that balances clarity, feasibility, and long-term performance. Our work prioritizes livability, constructability, and durability, ensuring projects remain resilient from early concept through construction.

Categories

Residential

Mixed-Use

Civic

Architecture

(002)

Urban Design

Our urban design work focuses on neighborhood-scale systems, public space, and development frameworks that support housing, civic life, and long-term growth. We approach cities as interconnected environments shaped by daily use, infrastructure, and policy realities.

Categories

Neighborhood Planning

Mixed-Use Districts

Transit-Oriented Development

Parks and Open Space

Urban Design

(003)

Research and Development

Research and development at OAO supports clearer decisions and better outcomes. We use applied research to test assumptions, evaluate feasibility, and inform design strategies before risk is locked in.

Categories

Visioning and Strategy

Technology and Visualization

Sustainability and Performance

Publications and White Papers

Research and Development

(005)

Laser Scanning

Laser scanning is a core component of OAO’s research and development practice. It allows projects to begin with precise, real-world spatial data rather than assumptions or incomplete documentation. By capturing existing conditions accurately from the outset, laser scanning strengthens decision-making across planning, design, coordination, and delivery.

Categories

Existing Condition Scanning

LiDAR and Point Cloud

As-Built Documentation

360 Site Capture

Laser Scanning

(004)

Fabrication

Our fabrication experience informs how details are designed, coordinated, and built. This knowledge strengthens constructability and ensures architectural intent carries through to execution.

Categories

Physical Design Models

In-House Mockups

Detail Prototypes

Assembly and Constructability Studies

Fabrication

(006)

Advanced Visualization

Advanced visualization supports clearer decision-making across design, coordination, and delivery. These tools help clients, consultants, and communities understand projects accurately before construction, reducing risk and improving alignment.

Categories

Virtual Reality

Design Visualization

Construction Coordination

Aerial and Site Analysis

Advanced Visualization

(001)

Architecture

We design residential, mixed-use, and civic architecture that balances clarity, feasibility, and long-term performance. Our work prioritizes livability, constructability, and durability, ensuring projects remain resilient from early concept through construction.

Categories

Residential

Mixed-Use

Civic

Architecture

(002)

Urban Design

Our urban design work focuses on neighborhood-scale systems, public space, and development frameworks that support housing, civic life, and long-term growth. We approach cities as interconnected environments shaped by daily use, infrastructure, and policy realities.

Categories

Neighborhood Planning

Mixed-Use Districts

Transit-Oriented Development

Parks and Open Space

Urban Design

(003)

Research and Development

Research and development at OAO supports clearer decisions and better outcomes. We use applied research to test assumptions, evaluate feasibility, and inform design strategies before risk is locked in.

Categories

Visioning and Strategy

Technology and Visualization

Sustainability and Performance

Publications and White Papers

Research and Development

(005)

Laser Scanning

Laser scanning is a core component of OAO’s research and development practice. It allows projects to begin with precise, real-world spatial data rather than assumptions or incomplete documentation. By capturing existing conditions accurately from the outset, laser scanning strengthens decision-making across planning, design, coordination, and delivery.

Categories

Existing Condition Scanning

LiDAR and Point Cloud

As-Built Documentation

360 Site Capture

Laser Scanning

(004)

Fabrication

Our fabrication experience informs how details are designed, coordinated, and built. This knowledge strengthens constructability and ensures architectural intent carries through to execution.

Categories

Physical Design Models

In-House Mockups

Detail Prototypes

Assembly and Constructability Studies

Fabrication

(006)

Advanced Visualization

Advanced visualization supports clearer decision-making across design, coordination, and delivery. These tools help clients, consultants, and communities understand projects accurately before construction, reducing risk and improving alignment.

Categories

Virtual Reality

Design Visualization

Construction Coordination

Aerial and Site Analysis

Advanced Visualization

Dark gradiend background
Dark gradiend background
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Current Ongoing Efforts

0+

Current Ongoing Efforts

0+

Current Ongoing Efforts

0+

Successful completed projects delivered by team

0+

Successful completed projects delivered by team

0+

Successful completed projects delivered by team

0%

Client satisfaction rate

0%

Client satisfaction rate

0%

Client satisfaction rate

0M+

Total completed project SF delivered across prior practice

0M+

Total completed project SF delivered across prior practice

0M+

Total completed project SF delivered across prior practice

Each project is more than a design. It is a foundation for lasting impact.

We focus on function, clarity, and adaptability, shaping spaces that perform well and avoid unnecessary complexity.

We focus on function, clarity, and adaptability, shaping spaces that perform well and avoid unnecessary complexity.

-MK

-MK

The faces behind the projects.

The faces behind the projects.

Be part of our mission

If you’re ready to create and collaborate, we’d love to hear from you.

We believe strong collaboration leads to better decisions. Our team works closely together to align design intent, technical rigor, and client goals at every stage.

Founder & Architect

at OAO®

Mariusz Klemens

“Architecture should clarify complexity, serve people first, and create value that lasts well beyond the moment it is built.”

Founder & Architect

at OAO®

Mariusz Klemens

“Architecture should clarify complexity, serve people first, and create value that lasts well beyond the moment it is built.”

Founder & Architect

at OAO®

Mariusz Klemens

“Architecture should clarify complexity, serve people first, and create value that lasts well beyond the moment it is built.”

FAQ.

FAQ.

Got questions? We’ve got answers. Here’s everything you need to know about working with us.

How long does it take to deliver a project?
icon

Timelines vary based on scope, scale, and complexity, but our approach is intentionally efficient and responsive. We begin with a prompt initial viability assessment to help clients quickly understand feasibility, opportunities, and constraints. From there, we establish a clear, realistic schedule tailored to the project. Drawing on extensive experience, we prioritize clarity, decisive progress, and disciplined execution to move projects forward without unnecessary delay.

Do you create custom designs or use standard solutions?
icon

Every project we take on is fully custom. Our process is research-driven and grounded in visioning, ensuring that each solution responds to its unique context and client goals. We don’t rely on templates, we design with precision, attention to detail, and a commitment to quality, delivering work that reflects both creativity and rigor.

What’s included in your design process?
icon

Our process begins with research and early visioning to clearly define goals, context, and opportunities. We then develop and test ideas through iterative design and close collaboration, refining each concept with care and precision. Throughout every phase, we emphasize clarity, attention to detail, and a clear path to execution. Our services are tailored to the scale and needs of each project, from single-family homes and renovations to mixed-use developments and urban master plans, always guided by rigor, creativity, and a commitment to quality.

What types of projects does OAO specialize in?
icon

OAO’s work spans architecture, urban design, and research-driven development. Our experience ranges from single-family homes and renovations to complex mixed-use developments, cultural and civic spaces, and large-scale urban and neighborhood master plans. In parallel, we lead research and development efforts that include visioning and strategy, participatory tools, design studies, technology-driven visualization, and experimental frameworks that inform built work. We tailor our process to projects at every scale, ensuring each outcome is contextually rooted, research-informed, and crafted with precision. Whether shaping a single building, developing a master plan, or advancing new ideas through R&D, we deliver thoughtful, adaptable, and enduring results.

How do you approach collaboration with clients and partners?
icon

Collaboration is central to our practice. We begin by listening carefully, establishing trust and clarity through open, direct dialogue. Our process is transparent and participatory, engaging clients, consultants, stakeholders, and communities as appropriate. By building a shared understanding early, we align vision, expectations, and execution, allowing each project to develop with purpose, creativity, and technical rigor.

What type of technical experience does your team have?
icon

Our team brings deep technical experience across building systems, construction detailing, and project delivery, informed by decades of work on large and complex developments. We apply advanced tools such as digital modeling, simulation, and visualization to support decision-making, coordination, and design quality throughout the process. Equally important, we collaborate closely with engineers, consultants, and allied professionals to assemble the right expertise for each project. This integrated approach ensures that our work is not only visionary, but also technically sound, buildable, and resilient over time.

Do you use AI in your work?
icon

We actively study and experiment with AI as part of our research and development practice. We view it as an evolving tool that can inform process, analysis, and internal exploration, and we continue to evaluate how it may responsibly support architectural practice over time. Our published work and project deliverables remain grounded in human authorship and design intent. We do not include AI generated images or writing in our outputs or publications unless it is explicitly labeled and clearly identified as such. Transparency, authorship, and accountability are central to how we work, and any use of emerging technologies is approached with care, intention, and clarity.

How long does it take to deliver a project?
icon

Timelines vary based on scope, scale, and complexity, but our approach is intentionally efficient and responsive. We begin with a prompt initial viability assessment to help clients quickly understand feasibility, opportunities, and constraints. From there, we establish a clear, realistic schedule tailored to the project. Drawing on extensive experience, we prioritize clarity, decisive progress, and disciplined execution to move projects forward without unnecessary delay.

Do you create custom designs or use standard solutions?
icon

Every project we take on is fully custom. Our process is research-driven and grounded in visioning, ensuring that each solution responds to its unique context and client goals. We don’t rely on templates, we design with precision, attention to detail, and a commitment to quality, delivering work that reflects both creativity and rigor.

What’s included in your design process?
icon

Our process begins with research and early visioning to clearly define goals, context, and opportunities. We then develop and test ideas through iterative design and close collaboration, refining each concept with care and precision. Throughout every phase, we emphasize clarity, attention to detail, and a clear path to execution. Our services are tailored to the scale and needs of each project, from single-family homes and renovations to mixed-use developments and urban master plans, always guided by rigor, creativity, and a commitment to quality.

What types of projects does OAO specialize in?
icon

OAO’s work spans architecture, urban design, and research-driven development. Our experience ranges from single-family homes and renovations to complex mixed-use developments, cultural and civic spaces, and large-scale urban and neighborhood master plans. In parallel, we lead research and development efforts that include visioning and strategy, participatory tools, design studies, technology-driven visualization, and experimental frameworks that inform built work. We tailor our process to projects at every scale, ensuring each outcome is contextually rooted, research-informed, and crafted with precision. Whether shaping a single building, developing a master plan, or advancing new ideas through R&D, we deliver thoughtful, adaptable, and enduring results.

How do you approach collaboration with clients and partners?
icon

Collaboration is central to our practice. We begin by listening carefully, establishing trust and clarity through open, direct dialogue. Our process is transparent and participatory, engaging clients, consultants, stakeholders, and communities as appropriate. By building a shared understanding early, we align vision, expectations, and execution, allowing each project to develop with purpose, creativity, and technical rigor.

What type of technical experience does your team have?
icon

Our team brings deep technical experience across building systems, construction detailing, and project delivery, informed by decades of work on large and complex developments. We apply advanced tools such as digital modeling, simulation, and visualization to support decision-making, coordination, and design quality throughout the process. Equally important, we collaborate closely with engineers, consultants, and allied professionals to assemble the right expertise for each project. This integrated approach ensures that our work is not only visionary, but also technically sound, buildable, and resilient over time.

Do you use AI in your work?
icon

We actively study and experiment with AI as part of our research and development practice. We view it as an evolving tool that can inform process, analysis, and internal exploration, and we continue to evaluate how it may responsibly support architectural practice over time. Our published work and project deliverables remain grounded in human authorship and design intent. We do not include AI generated images or writing in our outputs or publications unless it is explicitly labeled and clearly identified as such. Transparency, authorship, and accountability are central to how we work, and any use of emerging technologies is approached with care, intention, and clarity.

How long does it take to deliver a project?
icon

Timelines vary based on scope, scale, and complexity, but our approach is intentionally efficient and responsive. We begin with a prompt initial viability assessment to help clients quickly understand feasibility, opportunities, and constraints. From there, we establish a clear, realistic schedule tailored to the project. Drawing on extensive experience, we prioritize clarity, decisive progress, and disciplined execution to move projects forward without unnecessary delay.

Do you create custom designs or use standard solutions?
icon

Every project we take on is fully custom. Our process is research-driven and grounded in visioning, ensuring that each solution responds to its unique context and client goals. We don’t rely on templates, we design with precision, attention to detail, and a commitment to quality, delivering work that reflects both creativity and rigor.

What’s included in your design process?
icon

Our process begins with research and early visioning to clearly define goals, context, and opportunities. We then develop and test ideas through iterative design and close collaboration, refining each concept with care and precision. Throughout every phase, we emphasize clarity, attention to detail, and a clear path to execution. Our services are tailored to the scale and needs of each project, from single-family homes and renovations to mixed-use developments and urban master plans, always guided by rigor, creativity, and a commitment to quality.

What types of projects does OAO specialize in?
icon

OAO’s work spans architecture, urban design, and research-driven development. Our experience ranges from single-family homes and renovations to complex mixed-use developments, cultural and civic spaces, and large-scale urban and neighborhood master plans. In parallel, we lead research and development efforts that include visioning and strategy, participatory tools, design studies, technology-driven visualization, and experimental frameworks that inform built work. We tailor our process to projects at every scale, ensuring each outcome is contextually rooted, research-informed, and crafted with precision. Whether shaping a single building, developing a master plan, or advancing new ideas through R&D, we deliver thoughtful, adaptable, and enduring results.

How do you approach collaboration with clients and partners?
icon

Collaboration is central to our practice. We begin by listening carefully, establishing trust and clarity through open, direct dialogue. Our process is transparent and participatory, engaging clients, consultants, stakeholders, and communities as appropriate. By building a shared understanding early, we align vision, expectations, and execution, allowing each project to develop with purpose, creativity, and technical rigor.

What type of technical experience does your team have?
icon

Our team brings deep technical experience across building systems, construction detailing, and project delivery, informed by decades of work on large and complex developments. We apply advanced tools such as digital modeling, simulation, and visualization to support decision-making, coordination, and design quality throughout the process. Equally important, we collaborate closely with engineers, consultants, and allied professionals to assemble the right expertise for each project. This integrated approach ensures that our work is not only visionary, but also technically sound, buildable, and resilient over time.

Do you use AI in your work?
icon

We actively study and experiment with AI as part of our research and development practice. We view it as an evolving tool that can inform process, analysis, and internal exploration, and we continue to evaluate how it may responsibly support architectural practice over time. Our published work and project deliverables remain grounded in human authorship and design intent. We do not include AI generated images or writing in our outputs or publications unless it is explicitly labeled and clearly identified as such. Transparency, authorship, and accountability are central to how we work, and any use of emerging technologies is approached with care, intention, and clarity.

Have a project in mind?

By submitting, you agree to our Terms and Privacy Policy.

© 2025 OAO®

Let’s talk.

Tell us about your project, big or small. We listen carefully and help turn early ideas into clear next steps.

Quick response.

If you’re ready to create and collaborate, we’d love to hear from you.

Clear next steps.

After the consultation, we’ll provide you with a detailed plan and timeline.

Dark gradiend background

Have a project in mind?

By submitting, you agree to our Terms and Privacy Policy.

Let’s talk.

Tell us about your project, big or small. We listen carefully and help turn early ideas into clear next steps.

Quick response.

If you’re ready to create and collaborate, we’d love to hear from you.

Clear next steps.

After the consultation, we’ll provide you with a detailed plan and timeline.

Dark gradiend background

Have a project in mind?

By submitting, you agree to our Terms and Privacy Policy.

© 2025 OAO®

Let’s talk.

Tell us about your project, big or small. We listen carefully and help turn early ideas into clear next steps.

Quick response.

If you’re ready to create and collaborate, we’d love to hear from you.

Clear next steps.

After the consultation, we’ll provide you with a detailed plan and timeline.

Dark gradiend background

Whether your project is a single home, a major renovation, or a complex urban district, we guide the design process with clarity and care.

Whether your project is a single home, a major renovation, or a complex urban district, we guide the design process with clarity and care.

Mariusz Klemens

Founder & Architect

Mariusz Klemens

Founder & Architect


Licensed in Illinois and Michigan
Professional Liability Insurance Maintained

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© 2026 OAO® Open Architecture Office. All rights reserved.