How Environmental Site Investigations Shape Architectural Design

Tuesday, March 11, 2025

A Case Study Approach: Londonderry Car Wreckers

When architects begin planning a project, the site's environmental conditions can significantly impact the design, material choices, and construction feasibility. A smooth transition from Preliminary Site Investigations (PSI) to Detailed Site Investigations (DSI) is crucial for identifying constraints and opportunities early in the design process. This article explores how environmental site investigations influence architectural decisions, using the Londonderry Car Wreckers project as a real-world example.

Why Architects Should Care About Site Investigations

Before sketching a design concept, architects must consider:

What environmental risks exist on the site? (Contaminated soil, groundwater pollution, asbestos, unstable ground)
Will remediation or compliance measures impact the site layout or material selection?
How can environmental constraints inform a sustainable and resilient design?

Case Study: Londonderry Car Wreckers

The Londonderry Car Wreckers site required comprehensive environmental investigations due to its long history of automotive operations. Asbestos, heavy metals, and hydrocarbons were identified in the soil and groundwater, influencing remediation efforts and subsequent land use planning. For architects, this meant re-evaluating design approaches to align with environmental constraints.

Step 1: Preliminary Site Investigation (PSI) – Identifying Key Constraints

A Preliminary Site Investigation (PSI) helps architects and planners understand the environmental history of a site. This phase includes:

Desktop Study: Reviewing historical land use and existing environmental reports.
Site Walkover: Conducting an on-site visual inspection to assess current conditions.
Stakeholder Engagement: Consulting environmental specialists, planners, and regulatory bodies.

Architectural Relevance

At Londonderry, the PSI flagged potential contamination risks due to previous industrial activities. For an architect, this early-stage information influences decisions such as:

Avoiding subgrade developments (e.g., underground parking) in areas with known contaminants.
Identifying zones where certain materials may be restricted due to soil or groundwater conditions.
Assessing whether existing structures should be demolished or integrated into the design.

Step 2: Detailed Site Investigation (DSI) – Defining Design Parameters

If a PSI reveals potential risks, a Detailed Site Investigation (DSI) is conducted to further analyse soil, groundwater, and structural conditions. This phase includes:

Sampling & Laboratory Analysis: Identifying contamination types and concentrations.
Geotechnical Assessments: Evaluating soil stability, which influences foundation design.
Ecological Considerations: Assessing the impact on local flora and fauna.

Architectural Relevance

The Londonderry Car Wreckers DSI uncovered:

Asbestos contamination, requiring careful site remediation and restrictions on excavation depth.
Heavy metals & hydrocarbons in soil and groundwater, influencing drainage strategies.
Unstable subgrade conditions, requiring engineered foundations.

For architects, these findings meant:

Elevated Building Foundations – Due to soil instability and contamination risks, designs needed to incorporate raised structures or alternative footing solutions.
Strategic Stormwater Management – Contaminated groundwater required careful planning to prevent pollution spread. Permeable landscaping materials were not suitable in certain areas.
Material Selection – Some site conditions restricted the use of specific materials that could react with contaminants or pose long-term degradation risks.

Designing with Environmental Constraints in Mind

When faced with a site that has contamination or geotechnical challenges, architects can implement smart design strategies to work within these constraints:

Site Layout Adjustments – Placing buildings away from high-risk areas or integrating remediation strategies within the design.
Passive Design Solutions – Incorporating ventilation strategies for vapor intrusion risks or selecting elevated designs to minimise direct ground contact.
Sustainable Remediation Integration – Using bio-remediation zones, green infrastructure, or engineered capping solutions to manage contamination while enhancing site aesthetics.

Key Takeaways for Architects

Ask These Questions Before Finalising a Site Plan

What contamination risks exist, and how will they impact my design?
Will remediation efforts limit my ability to excavate, landscape, or develop certain areas?
Do site constraints affect my material selection or construction methods?
Can I incorporate sustainability solutions to address environmental challenges?

By working closely with environmental consultants during PSI and DSI phases, architects can proactively design buildings that respond to environmental realities, ensuring both compliance and long-term resilience.

Need Environmental Site Investigation Support?

At Raw Earth Environmental, we specialise in site investigations that help architects, planners, and developers navigate complex environmental challenges. Whether it’s contaminated land assessments, remediation strategies, or geotechnical analysis, our team provides the insights you need to create sustainable, compliant, and future-proof designs.