Posted by: nedpelger | November 17, 2009

Learn to Calculate Loads…Or Face the Consequences

I think everyone in construction should be able to roughly find the volume of things, have a sense of their density and be able to make a decent calculation of what they weigh. For example, a tree being removed next to a house. Say the tree is about 3′ diameter with 15′ of main trunk and branches that go another 25′.

Just to keep it simple, assume a 3′ x 3′ x 40′ volume x 40 pounds per cubic foot = 14,400 pounds. Everyone involved in this industry that faces us with all sorts of odd challenges should be able to do a similar calculation. We should all know that wood = 40 lbs/cf, soil = 100 lbs/cf, concrete 150 lbs/cf and steel = 500 lbs/cf.


Yesterday in Santa Rosa CA, a crew worked to remove a tree and ended up using the crane boom like a knife to slice the house in half. As in normal in these situations, the workers claimed it was a freak accident. Fortunately no one was hurt. The crane boom missed the worker in the tree by about 4′ and the homeowners were dealing with a car accident they had earlier in the day. A day they won’t forget.

As you work through your day, think about what things weigh. Get adept at volumes, densities and weights and avoid injuries to yourself and others.




  1. Gee.. doesn’t anyone “have an app for that” ?

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