Underwater Concrete for Dummies

dock pilings set on concrete

It's somewhat unusual for our staffers to run across a freelanced how-to post addressing something none of them has ever done. When they do, though, they still administer the "sniff test" to see if the freelancer in question is as knowledgeable as he or she claims. Today's one of those days: "How to Pour Foundation Concrete Under Water," at Hunker.com had that distinctive odor of bull, even if author Cassandra Tribe is a "retired general construction foreman."

Like many an eHow.com¹ writer, Tribe decided to twist the OQ's question into the answer she wanted to give. That's why she opened by saying,

"When building a boat ramp or a bridge you will have to learn how to pour foundation concrete underwater."

We rather doubt the OQ was building a bridge: we hope that people building a bridge already know how to pour the foundation! We also doubt that he or she was building a boat ramp. That leaves piers, docks, and other small structures your average homeowner might want to build. With that in mind, we think that Cassandra's extended instructions on how to build a friggin' cofferdam are, at best, off-topic.

Instead, Occam's Razor suggests that Tribe's post might have been more useful to more readers had she pointed out what the Concrete Society says on the topic:

"Most underwater concrete is mixed on the surface in the conventional manner and then placed underwater by one of a variety of methods.

Properly mixed concrete is a stable material with a density of more than twice that of water. Once in position it will remain unaffected by the water in which it is immersed unless it is subjected to agitation or movement while it is setting. Concrete hardens as quickly underwater as it does in the dry [sic]."

In other words, if you need to pour a little concrete under water to anchor your pier, you can mix it up and pour it into a form, just like you would at the surface.

While we're here, we have to laugh at the critical mistake in Tribe's original eHow post, where she warned her readers, "Do not attempt to construct a cofferdam that is deeper than 2 feet with an engineer's design." Somehow we suspect that it should have been without instead of "with." The bad proofreading notwithstanding, we're convinced that Tribe's diversion into cofferdam construction and her ensuing 11-step process that includes just one mention of concrete is not what the OQ wanted. Tribe's answer may be technically correct (and we have no reason to doubt it), but it's for the wrong question: hence her Dumbass of the Day award.

¹ Hunker is one of several niche sites where Leaf Group is shoving its eHow content.

copyright © 2018-2022 scmrak

DD - FOUNDATIONS