Historic buildings offer a look into the past, but compared to modern structures have their own unique features terms of structural details and ageing. This leaves surveyors with a number of pros and cons when it comes to using BIM for historic buildings.
Cons
BIM is great but it isn’t (currently) formatted in a way that can easily cater to the needs of surveyors when it comes to modelling historic buildings. These buildings have different needs and complications that modern buildings don’t have or at least don’t have yet. As historic buildings tend to having smaller, more intricate details than current buildings, it is more difficult to capture these details. It takes longer to survey these details and then when they are inputted into BIM they may not be accurate as BIM does not have the capacity to recognize them. In addition to potential inaccuracies, the details that are captured may not reflect their true current state.
One example of this is surveying door frames. Where in historical buildings they may be uneven or have started to sag, BIM will show the door frame the way a modern door frame would be modelled, with straight lines and angles. This can lead to gaps in how the information is held in the model, which could affect future projects when accessing the model.
However, it would be difficult to ensure that every style of feature can be accurately modelled, due to the differences in architectural styles and building standards used in historical times. In historic buildings that have experienced restorations, it can also be difficult to model which parts of the structure might be newer or older than other features.
Pros
Despite its shortcomings, BIM is still an excellent tool to use with historic buildings. One of the pros is that it using BIM is that is compiles the most relevant data bank for the structure. Architects, facilities management teams and other surveyors will still need access to this type of information.
And while BIM can leave gaps in some of the structural information, using it for historic buildings can fill in the gaps when it comes to lifecycle estimates, which is of particular importance when maintaining these buildings. This means estimates can be assisted by this data making them more accurate and true to picture as well.
Especially with historic buildings, information that is relevant to be BIM might be held in numerous sources. BIM brings this together to give the best picture overall of the data. Having all this data in one source makes it more accessible and saves time on finding it individually.
It also creates a valuable resource for research and appraisal that can help to inform conservation and improve decision making as more data is available to help support the decision making process.
Conclusion
As BIM is becoming more and more a part of the overall design, building and maintenance process, it is hard to ignore that historic buildings can benefit from this process. BIM for historic buildings is a team effort that requires input and collaboration from multiple disciplines.
It can be used successfully with some caveats. The way the results are interpreted relies upon knowing the limitation of historical buildings in modelling and building this awareness is something that takes time and experience.
It will be interesting going forward to see how BIM evolves to accommodate the ever-growing number of historic buildings that will all need accurate data and modelling.
