Expert: Richard Taylor, AIA - 6/25/2008

Question
hello, we got a new deck finished today, and two of the planks looked cracked, like when you put a nail through a piece of wood, and it cracks it longitudinally. One of them is one of the actual deck legs. The other is a transversal plank, which is then doubled by a plank that is not cracked. is it ok if a brand new deck has these cracks, i really don't know how to assess if the contractor did a good job. the deck looks ok, feels solid, aside from these cracks. thank you.

Answer
Good morning Liana - thanks for your question!

A certain amount of defect is expected and acceptable in new lumber including twisting, bowing, checking, cupping, knots, wanes, and warping.  It's the degree to which the defects affect the strength that count.

In your case it sounds like you have checking, which is caused by uneven shrinking of the wood during drying.  This is more common in pressure-treated wood (which is probably what you have) because of the way the preservative is applied to the board, and because the wood itself is generally lower quality.

Checking isn't generally a structural problem, since checking occurs before the wood is graded and shipped (in other words, the checking is taken into account in assessing the structural strength of the board).  But keep an eye on it - if the size of the "cracks" increase you may have a more serious problem.

You might be concerned with the aesthetics of the cracks if they're in the decking itself - if you are, your contractor should be willing to replace any unsightly boards.  You have the right to expect the finished surface of the deck to be mostly free of defects!

As far as the cracks in structural members, make your concerns  known in writing to the contractor, and ask him to look in on your project 6 months or a year from now.  If the cracks are worsening, he should be willing to correct the problem.  I assume you have a warranty from him?  Check you state laws, many require a basic warranty on structure (in Ohio it's 10 years).

Hope this helps!

Richard Taylor, AIA
www.rtastudio.com
www.rtaplans.com