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Here are some resources that can help you understand the art of reading blueprints like a pro:
Books
The de-factor reference for learning how to read blueprint is and has been “Blueprint Reading: Construction Drawings for the Building Trade”. You can get it from Amazon: https://www.amazon.com/gp/product/0071549862
Another great read (also available on Amazon) is Hammer's Blueprint Reading Basics: https://www.amazon.com/Hammers-Blueprint-Reading-Basics-Charles/dp/0831136146
Online Training
Here are some awesome online resources:
https://vdci.edu/course-bundles/blueprint-reading-fundamentals/www.aspenational.org/mpage/PRE
(If you're new to construction estimating, ASPE offers comprehensive training: https://www.aspenational.org/BlankCustom.asp?page=EstimatingAcademy)
https://www.archtoolbox.com/design-document/construction-documentation/
Videos
And if you’re a “gotta watch how it’s done” sort of person, here are some great YouTube videos on the subject:
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