Building Information Modelling: Defining the Correct Level of Detail

Posted 05/02/2026

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Building Information Modelling: Defining the Correct Level of Detail

Building Information Modelling (BIM) is most effective when the required Level of Detail is clearly defined in accordance with the project’s information requirements at the point of commission. Under the UK adoption of ISO 19650, a measured BIM survey should be developed to support a defined purpose of information, whether for feasibility assessment, design coordination, technical design, or construction planning.

At XP Surveys, we deliver measured BIM models that are accurate, structured, and aligned with UK ISO 19650 workflows, supporting effective information management throughout the project lifecycle.

Level of Detail and Level of Information Need

In line with ISO 19650, the level of detail within a BIM model should be appropriate to the project’s Level of Information Need, balancing geometric detail, information content, and documentation requirements. The specified level has a direct impact on modelling efficiency, file performance, coordination accuracy, and overall cost.

Over-modelling can introduce unnecessary complexity and risk, while under-modelling may prevent the information from meeting its intended use or supporting effective decision-making.

For clarity, BIM levels of detail can be broadly related to traditional UK 2D drawing scales:

LOD 1–2 (Approx. 1:200)
Overall building form, primary elements, and general spatial arrangement. Suitable for feasibility studies, massing analysis, and early-stage information exchange.

LOD 3 (Approx. 1:100)
Accurate architectural geometry appropriate for design development, spatial coordination, and multidisciplinary review.

LOD 4 (Approx. 1:50)
Enhanced geometric definition to support technical design, clash detection, and coordinated design outputs.

LOD 5 (Approx. 1:20)
Highly detailed and information-rich models suitable for construction-level outputs, fabrication reference, and asset information development.

Information Requirements and Early Definition

Defining the required level of detail at survey stage ensures the measured BIM model aligns with the project’s Exchange Information Requirements (EIR) and supports efficient information production and exchange. Early definition reduces the risk of scope creep, rework, and misalignment between appointing parties and appointed parties.

XP Surveys works closely with clients, designers, and contractors to help establish clear information requirements and deliver BIM models that integrate seamlessly within a Common Data Environment (CDE), in accordance with UK ISO 19650 standards.

UK-Focused BIM Delivery

Our measured BIM services support both public and private sector projects across the UK, providing reliable survey data that underpins informed decision-making, coordinated design, and efficient project delivery.

XP Surveys provides technical guidance throughout the commissioning process, ensuring BIM deliverables are proportionate, compliant, and aligned with your project’s information management strategy. Alongside this consultancy, we conduct precision measured building surveys and topographical surveys to capture full property dimensional and structural data, providing a complete digital foundation for any development.