The tendency to believe that BIM is the sole preserve of new-build construction overlooks the advantages it can have for the management and refurbishment of existing buildings. Partner at Baily Garner – Rob Ireland, wrote the following article for the RICS Built Environment Journal to discuss.

Perceptions about building information modelling (BIM) are changing, and surveyors are seeking to develop the use of this technology in existing buildings. However, there are a number of obstacles to implementing BIM in such assets, which may account for the inconsistent uptake. [emaillocker id=”71749″]

BIM is a process for creating and managing information on a construction project that can then also be used across the building’s entire life cycle. There are four defined BIM levels, with each increasing the extent of collaboration and shared data.

The technology depends on coordinating the initial input of reliable information into a project information model (PIM), which is developed through the design and construction phases. After completion, relevant information is then transferred into an asset information model (AIM).

Both of these models consist of a number of different files that are created and managed in the BIM process, incorporating information from sources such as specifications and data sheets.


The use of BIM streamlines projects from inception to completion. All documents produced as part of the design or asset management stages refer back to the same PIM or AIM, which provides a unique source of information for the project. Interested parties are then able to analyse this information and extract what is useful to/necessary for them, reach decisions and act in an informed and efficient way.

At the design stage, efficiencies are achieved by:

  • in-depth analysis of building performance, including environmental impact, cost and project duration
  • automated quality checks, such as clash detection and data validation
  • use of libraries of pre-made, data-rich, re-useable objects.

BIM-integrated software uses the information that the model contains to help optimise project workflow. It allows automated data extraction to ensure all disciplines work from a single information source; reduces the amount of rework required, by enabling issues to be identified before construction; and develops clients’ understanding of how the building will perform.

Various software packages can be connected with each other in BIM, providing benefits as the design develops throughout the life of the project. For example, updates to layout or changes to specification can automatically be identified by costing software, to provide clients with live information on the potential implications of alterations throughout the design period. This can significantly increase certainty over cost and duration on refurbishment projects, where full information about the original construction may not be available and where there is a risk of unforeseen changes as the design develops.

Contractors will be able to use the model to understand the design, inform off-site manufacturing, and develop project phasing and construction programmes. Given the challenges of undertaking works in occupied buildings, the potential to interrogate the programme alongside proposed works could offer significant benefits.

At Baily Garner, we have seen such benefits during the construction stage, demonstrated in our work on a regeneration project in Westminster when we used Autodesk BIM 360 to inspect works on site. The software enabled the design team access to project data in real time, and allowed the completed installation to be compared against the 3D model on a tablet, streamlining both the quality assurance and project completion processes.


Alongside the benefits of BIM for contractors and consultants, many clients also acknowledge the potential for digitisation in their own organisations. In particular, a digital asset register can be produced on completion of the works to support effective future management of facilities and assets. BIM helps improve the quality of completed work, but will also help clients achieve the Hackitt Review’s aim of providing a golden thread of building information.

At Baily Garner, we work with housing association clients that are creating a digital, data-rich portfolio of their built assets. This will enable them to collect, record and analyse information on their existing buildings in real time, and reduce reliance on regular stock condition surveys.

Building surveyors will therefore need to embrace the increased use of BIM, exploiting its potential to inform clients on their asset management and maintenance requirements, and supporting inspections of building fabric and components.


If they are to make increased use of BIM, building surveyors need to embrace innovations and new ways of working, moving on from traditional behaviours. Effective, beneficial collaboration between all parties is central to this – but fostering and maintaining such cultures is always challenging.

Ensuring early clarity about clients’ intended use for BIM on refurbishment schemes , beyond project completion, is critical. A detailed review and understanding of the employer’s information requirements is essential, for instance, and this document should set out the level of detail and information needed for the design, construction and handover phases.

Engaging the supply chain can also prove problematic. Without appropriate requirements for the levels of data that products need, significant time and resources may be spent inputting this information into the PIM and AIM. This process will be much easier if the supply chain is cooperative in the modelling process


Baily Garner has direct experience of this challenge through our work with the Metropolitan Police Service (MPS).

The MPS is in the process of transforming and consolidating its estate, developing retained buildings to provide facilities fit for a modern police service. The works involve adapting buildings to provide more open plan and agile working spaces and incorporating the latest IT.

The obstacles of working in occupied buildings are exacerbated by the need for the MPS to maintain operations. This has made it challenging to achieve the MPS’s BIM standards; so, in conjunction with the client, a phased approach has been developed that involves:

  • a scan of the building envelope, ensuring accurate location of all key external elements
  • a full scan of accessible common parts, including staircases, storage areas and risers
  • intrusive surveys to agreed locations in the building to ensure the relevant structural detail in the model
  • production of a structural model that is fully integrated into the overarching building model.

Creating a model of suitable accuracy this way then allows design development. As projects progress, further scans of the building can be undertaken during the strip-out and first and second fix stages to increase the accuracy of the model.


The opportunity for BIM to support existing built assets in the future is significant, particularly when linked to asset and facilities management,whole-life costing and incorporating programmes into the models.

The COVID-19 outbreak has also brought alternative working practices into focus, in particular when movement to and around sites is restricted. The BIM environment is certainly suited to helping in these circumstances.

BIM and other technological progress in the industry opens multiple new avenues for surveyors, such as digital quality and quantity control or portfolio surveys. As a profession, therefore, we should embrace BIM as an opportunity to expand and enhance services, stand out and be competitive.