Thoughts on the Engineering Industry

A blog covering engineering, technology and business topics

Archive for the month “February, 2014”

Benefits of BIM Modeling in Project Pricing for Head Contractors and Subcontractors

     Hello.  How is everyone doing?  Today I would like to discuss the statistical breakdown of the benefits in project pricing BIM modeling can provide for the head contractors and subcontractors involved in the design process.  BIM modeling is something that is collectively touted by most innovators in the building and infrastructure design/build field.  However, it would be helpful to understand who has the most motivation to implement improved BIM modeling.  As stated by David Mitchell, “For different types of projects the people you need to engage, changes. We need to acknowledge that the savings arising out of a building project differs significantly to those of a civil or resource project.  There also needs to be an appreciation of when a construction contract or subcontract is formed as well as the type of construction contract that has been entered into.”  Therefore, the issue is approached in regards to those factors.

For a commercial scale building project, the indirect cost such as design and overhead management amounts to 17% as compared to 83% for the construction costs.  In addition, the ratio of margins between subcontractors and contractors is 7 to 1.  Therefore, it benefits the subcontractors the most to apply the BIM modeling.  However, when a civil project is considered, the head contractor sees most of the benefits because subcontractors only control 17% of the costs.  The resource sector has some interesting statistics as well.  First of all, for a pipeline, the indirect cost is far greater at 45% of the cost going to head contractors.  In addition, the head contractor owns the material production plant/labor and the resulting cost accounts for 83% percent of the other 55% which amounts to an additional 46% of the direct cost and 91% of the overall cost.  Therefore, in this case, the head contractor holds a large portion of the cost control.  However, when building a refinement plant there are some critical differences.  There is a similar level of indirect cost cost at 45%, but the subcontractor sees 88% of the direct cost in this case.  The result is the subcontractor seeing 48% of the cost of the project as compared to 9% in the previous example.

The above statistics are interesting for several reasons.  The first one, as stated in the article, is the fact that BIM modeling is implemented by head contractor and other associated designers; yet in some cases, the subcontractors see the benefits.  Seeing as changes in pricing are based on estimation based on previous projects, pricing benefits aren’t planned for in the budget as efficiently, and, depending on the project and head contractor, a subcontractor could see large and consistent benefits.  This means that the benefits of using BIM might not be maximized aside from time and documentation for the head contractor in that situation.  And if it is a case where head contractors see a large amount of the cost savings, they can more readily pass along the cost saving of BIM modeling. But the subcontractors may not be motivated to help improve the BIM modeling because it doesn’t help their bottom line.  For both of these reason, it makes sense why it is most common for head contractors and designers to push for improvements and BIM modeling.  However, an often overlooked requirement is that the subcontractor needs to work with the head contractor in implementing the improvements and have proper motivation to pass along the savings the see the full benefit for everyone involved with the project.

What is your opinion on BIM model implementation in regards to subcontractors and head contractors?  Are there any ways to promote a shared interest in BIM modeling?  Thanks for your time and have a good week!

The Application of Biologically Grown Materials to Building Design

Hello everyone, I hope y’all had good weekend.  Today, I want to talk about some new building materials being researched that are biological produced in a replicable process.  One of the common characteristics is that these materials will involve bacteria or something else derived from organisms.  The fact that these materials don’t require significant carbon output is one major benefit.  Another benefit for most of these materials is that they are actively reproduced over time once they are installed as well.  The building materials are described below with some insight on possible benefits and issues.

bioMason Bricks

The bioMason brick is a brick of sand and cementitious material in which the cementitious material is created using a bacteria.  The brick mixture is created and over the course of 5 days the bacteria solidifies into a coral type material with the strength of a normal brick.  The major benefit for this innovation is that it doesn’t require the heat and raw materials used in creating normal bricks; this reduces the cost of the brick by 40%.  They are currently conducting experiments to research bacteria creation using the following materials: urea, salt and yeast extracts, and seawater.

I see this having one major benefit – it would not significantly change the design and build process for masonry.  Masonry strength is mostly determined by the strength of the mortar as long as the masonry unit strength doesn’t change significantly.  The benefits of the bioMason bricks combined with the low technology change requirement makes this much more effective.

Mushroom Insulation Material

This is a stiff insulation material using plant stalks and husks combined with Mycelium.  There are two forms of application being tested currently: growth inside the wall and spray on insulation.  The insulation is fire resistant and fully compostable.  Additionally, it does not contain formaldehyde or any other harmful organic materials.  This same material can also be used as compostable packaging material.

There are several benefits to this material.  Like before there is no significant change to the other building processes related to it.  It also has great applications outside of this usage alone and is completely compostable once it is not needed anymore.  The only drawback I can potentially see is there being an organic material harmful to humans that is unknown as of yet – similar to what happened with Asbestos. It has great potential overall though – it is my recommendation that more health testing be done before large scale usage.

Self Repairing Concrete:

Research is being conducted on a bacteria that can be used to repair concrete as it ages.  Bacteria engineered to thrive in dry climates is being created to be placed in the concrete mixture.  The bacteria would release Calcium Carbonate as part of the waste process which would fill the holes and cracks over time.

There is one possible major benefit I see – the reduction in maintenance required for the concrete designed this way.  However, more research would be required to determine it’s efficiency.  Additionally, nothing is mentioned about resources and energy required to produce this bacteria; if it requires a high amount of energy and time/raw material resources, it may become impractical to use.  I might also add that the issue of infection might come up here as well; but if the claim is true that it is bacteria that thrives in dry climates, the danger to living organisms would be greatly reduced.

What is your opinion on these possible advancements?  Can you see them being used in the future?  Thank you for your time and have a good week!


Wollenhaupt, Gary,”Self-Repairing Concrete Could be the Future of Green Building”, Forbes Online, January 6, 2014,

High Performance Energy Saving Design for the Karuna House – Window/Door Design

Passive House Green Home Building Tips: Karuna House Windows & Doors

Hello everyone! Today I would like to go back to my series of posts outlining the design and construction of the Karuna House.  The topic for this post will be the selection and resulting benefits of the improved windows and doors.  Windows and doors are the biggest holes in the building envelope above ground.  These innovations are what allow the HVAC systems to reach their maximum efficiency.  Additionally, windows and doors are also a major aesthetic concern and these aesthetic factors play a big role in the decision process.

The Karuna House uses triple glazed, high solar heat gain, R-8 windows with a very thin frame.  This type of window has an increased level of heat gain, but significantly improves the building envelope by allowing additional insulation to be placed around the frame.  The triple glazed window also has a well documented performance history because it has been in use since the 70’s in Scandinavia.  For the exterior doors, the Karuna House uses Optiwin doors.  These doors are thick with insulation in the middle and airtight with multi-locking mechanisms to ensure a tight seal.  To help with the heat gain issue for the windows, a shading system that can be lowered over the windows was installed.  This has an additional benefit of being modern and aesthetically appealing.  The triple glazing also provides a very clear view through the glass which adds to the modern, aesthetic appeal.  To further improve indoor conditions, these windows and doors increase comfort by reducing the draft found near the window and door openings.  All of the benefits above combine to reduce the impact on the mechanical systems which allows for a simpler, more efficient system to be used.

Overall these systems are simple and nothing too complex.  However, these systems apply the same philosophy that is applied to the building envelope in general – simple and efficient solutions to problems.  Furthermore, the philosophy applied to the building envelope, windows, and doors altogether should reap a lot of benefits for the mechanical systems and the energy usage correlated to that.  The take away here is very similar to the previous post on the Karuna House – a little a effort put into finding cost efficient improvements to small elements of the house can improve the overall efficiency a lot.

What do you think about the window and door improvements on the Karuna House?  Are there any issues that need to be addressed or  improvements that can be made?  Thanks for your time and have a good week!


Hammer & Hand,”Karuna House: Windows and Doors”,

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