A History Lesson

There are many useful sources of information to draw upon when an engineer is engaged to perform a Property Condition Assessment (PCA). There are sometimes existing drawings and other documentation to review in advance, and of course the on-site inspection. But Google Earth is another useful tool that is less well known.

Most people are familiar with Google Earth to some degree and some of the useful features to help with your work. Maybe more so if you do Property Condition Assessments (PCAs) for a living!

There are time-saving advantages to using the measure tools in Google Earth if you need to quickly acquire roof areas or asphalt areas for the purpose of cost estimates in PCA reports. Google Earth can approximate the length of a line or the area of a polygon.

But what about identifying the ages of the roofing system or the asphalt paving? Yes, that too! The engineer can use Google Earth to review these aspects of the property in advance to look for any obvious changes in the history of the building through archived Google Earth images.

Here is how to do that:

In the top tool bar there is a button for the history of the image.

A slider will appear at the top and you can go back in time.

Let’s look at a couple of examples. First for a roof:

You’ll notice that the roof pictured in this example has been replaced in the period between October 2015 and September 2016, and another change of note has occurred with the apparent removal of two roof-top mechanical units. Prepared with this information the engineer can make a note to inspect the areas of change to ensure that the work was done well.

Then for asphalt paving:

A picture is worth a thousand words!

Carson Dunlop Weldon & Associates Ltd. (CDW Engineering) is a consulting engineering firm that specializes in building inspections, design and education. The team of consultants at CDW Engineering has been selected not just for their technical abilities, but also based on their superior communication skills. The result is a company that has the technical know-how, but just as important, the ability to convey information concisely to the layperson.

Article by Richard Weldon, P.Eng., LEED AP, President of CDW Engineering in Toronto, Canada.
www.CDWengineering.com                                  Richard@CDWengineering.com

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