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BIM: What It Is And Why Roofers Should Care

By Ray Smith, AppliCad

Largely Forgotten History

Back in the mid-1970s, a bunch of very clever people got together and tried to define procedures for exchanging information among Computer Aided Design (CAD) systems in the aerospace industry. The intention was to reduce costs by defining something once and reusing the design data all the way along the design, testing, manufacturing, distribution and repair life-cycle of that product. The driver was the number of companies getting involved in automated manufacturing in the ‘70’s, all with egos and their own ideas on how CAD data was to talk to complex machine tools.

This resulted in some very heavy hitters such as Boeing, General Electric, Xerox, Computervision and others getting together under the auspices of the United States Air Force (USAF) to agree on such a standard. Using a bit of translation software developed by Boeing (and sold to the USAF for one dollar) as the starting point, the Initial Graphics Exchange Specification (IGES) standard format was born. After many committee meetings (one can only imagine), the IGES vendor-neutral file format was first published in 1980.

A more detailed description and some more history can be found in the usual way.

The point is that IGES was potentially the way forward for all other industries, not just defense component manufacturing, but engineering and architecture as well. The problem was that the level of detail needed to adequately specify every single product, and how that product was to be manufactured and used with every other product, including its specific technical details, resulted in the IGES specification becoming such an unwieldy document that it largely remained where it was first intended – component manufacturing. But the seed was planted and the concept proved to be useful.

As it turned out, engineers and architects have had the same problem (redrawing everything over and over) and we all agree that this hasn’t been, and still isn’t, very efficient. For years, every stage of a job was drawn and redrawn to suit the specific requirements of the drawer/designer. It was by no means efficient, but it was at least manageable.

Standardized Processes

With the rocket scientists at USAF proving that component manufacturing could be standardized, it begged the question: why not buildings?

The notion of Building Information Modeling (BIM) was first floated in the 1990s, appearing initially in various discussion papers around the world. It didn’t really gain any traction though until 10 years later when Autodesk, the CAD software heavyweight, released an industry paper outlining how they saw the BIM world. All other major CAD vendors also claim to have done much the same thing at the same time. It is generally recognized that the first effective implementation of BIM was by Graphisoft in their ArchiCAD design software, under the heading of ‘Virtual Building’.

Curiously, the BIM concept has been expanded way beyond simply standardizing the definition of the components of buildings and the buildings themselves, and now includes ‘places’. To quote Wikipedia:

Current BIM software is used by individuals, businesses and government agencies who plan, design, construct, operate and maintain diverse physical infrastructures, such as water, wastewater, electricity, gas, refuse and communication utilities, roads, bridges and ports, houses, apartments, schools and shops, offices, factories, warehouses and prisons.

Places? Really? How hard to implement does something have to be? Apparently as hard as we can make it. The intentions are honorable and in time, very useful, especially at the ‘macro’ level. But taking BIM beyond the building and into the local environs is making a hard job very difficult.

A US government committee has developed the following definition:

Building Information Modeling (BIM) is a digital representation of physical and functional characteristics of a facility. A BIM is a shared knowledge resource for information about a facility forming a reliable basis for decisions during its life-cycle; defined as existing from earliest conception to demolition.

So the traditional process of designing a building, situating it in its local environment using 2D drawings, has had to now be extended into 3D. This is so that the true spatial representation of the structure can be visualized, helping designers sell their vision. For many, this is quite a difficult step to take. They are simply not trained to think in 3D, let alone create 3D models of everything.

For BIM to work, the 3D model has to be enhanced with other details such as cost. If you store cost then you will store the manufacturer's and the supplier’s details as well, and all sorts of other information such as repair and maintenance information, so that the ultimate user doesn’t have to go chasing the information.

The 3D Model for BIM

Backing up for a minute, the not-so-obvious advantage of the 3D model is that any change to the model is automatically reflected in the traditional 2D views used to describe the structure, and a result of the 3D model. When you model in 3D, the plan and elevation views are extracted from the 3D model – you essentially get a model view (3D) and construction views (2D). The use of BIM requires every element used in a project, right down to the last nut, bolt and screw (in theory at least) to be defined in the 3D model, thus carrying with it all the attributes for selecting, costing and ordering; completely automating the project management process. Let’s just stop and think for a moment – this is a mountain of work and who is going to do it? More importantly, who is going to pay for it to be done?

The BIM concept allows all the professionals in a project to be quite literally on the same page. The information contained in the 3D model, and every component of it, can be handed from the design professionals (the surveyors, civil and structural engineers and architects) to the contractors and his/her sub-contractors.  

BIM is especially useful during construction as it is designed to provide cost and timing data to aid with project management. And it doesn’t stop there. The use of the BIM goes further because the data used to build the structure may then be used to service and maintain the structure. When the structure or facility is completed, the BIM data can then be handed to the facility managers, building owners and service providers to maintain the facility. One can easily imagine how powerful this process is, especially as structures become increasingly complex.   

The most obvious benefit of the use of BIM in construction is that it stops the ‘leaking’ of information as a project progresses through each stage of its life-cycle. It is difficult to apply BIM to old structures, but not impossible.  

Going forward, the use of BIM is so obvious that it is a wonder that it has taken so long to get this far. Yes the challenges are significant and the amount of information is immense, but it’s not like the information is not available. It is just that it is in so many collective heads. BIM brings it all together and allows everyone to use it.  

We design it, describe it and define it ONCE, then we use it over and over. I am sure someone has attempted to calculate the cost of people re-drawing, re-documenting everything, every time a new guy touches it, and then prints it. The cost must be enormous. But what about the cost of not doing it? That is surely greater.

One might consider the implementation of BIM as one big exercise in socialism – no one is offering to pay for all this work to be done, but everyone is expected to do it, for the greater good. What a concept!   

There is no escaping BIM. It has to come if the industry is to continue the improvements to efficiency and productivity. Indeed, the wide adoption of BIM is likely to result in the single-most-significant improvement to processes in the building industry since the adoption of CAD and CAM (Computer Aided Manufacturing). Having all the information stored electronically and in one place will reduce time, it will reduce errors and will improve productivity and accuracy. To my mind BIM equates to efficiency and in the case of buildings it has been proven to be effective.    

Implementation of BIM

To underscore this point, in 2011, the UK government published its BIM strategy and requires collaborative 3D BIM with all project and asset information, documentation and data being electronic. They require this to happen by 2016, and that is now! The Institute of British Architects has been keeping a watching brief on the progress of the adoption of BIM and they report that it has increased from 13% in 2010 to 48% in 2014. We are now well into 2016 and the UK Government’s deadline has essentially passed. I am sure that the number is now much higher and I would expect that they have largely achieved their goal.

I understand that in the US, all the appropriate people are still just talking about it, with many questions over what it’s going to be called apart from anything else. What can I say? The US is behind the 8-ball with a lot of work to do to catch up.

How does this affect roofers?

At one level it will have no effect at all. Your material will still be delivered to site and you will install it to the expected professional standards. However, expect that the specification for the installation and use of the roofing products will be available as part of a BIM model, and don’t be surprised if you are expected to access that information via a software program for reviewing project information provided by the contractor that is accessed on the internet (aka ‘the Cloud’) using your favorite web browser. You might do this from your pickup truck or while standing among the materials on the job site or sitting in front of your favorite coffee place. Typically however, you will have done this at the office at quotation stage, using the exact same information that the designer reviewed when they specified and modelled the job.

BIM Is Not Free

The cost for a roofer is in the implementation of systems and processes for using this information. It is like a magic black box that holds all sorts of wonderful secrets and you have to figure out how to extract them.

It must be said that all manufacturers, at least those that intend to stay in business, have all their specifications available for download from their web site already. The big difference with BIM is that the correct information for the current project is stored with the project, you don’t have to go chasing it and possibly finding the wrong information.

BIM on its own is not intelligent, it will not ring a bell when you need to do something.   It is information. It is what we do with that information that is clever. We need software and systems to extract, sort and review this information, displaying the key parts for our specific use. The tools to do this for each application must be developed, they must be implemented and people trained to use them. These steps have a cost too and some of the costs are recurrent costs – training for example.

BIM is the future of project design and management. Don’t ignore it. AppliCad has had an import BIM data function in their Roof Wizard software for years. We are just disappointed that no-one, at least to our knowledge, has ever used it. WHY NOT! It saves time, increases productivity and improves accuracy. It really is an obvious solution to ongoing improvements across the roofing industry and especially helpful for the metal roofing industry where accuracy is critical.

Author Ray Smith is Managing Director of AppliCad USA Inc and has 43 years’ experience with CAD/CAM and business systems. He has run his software development business targeting the roofing and cladding sector for 25 years and exports software from their head office in Australia to 148 countries. To learn more, visit

About AppliCad

AppliCad USA Inc. is a specialty CAD applications software development company focused on the needs of the roofing, cladding and solar industries. To learn more,visit

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