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Bellingham WA Home Inspections (King of the House) Wood to Soil

By
Home Inspector with King of the House Home Inspection, Inc. Home Inspector Lic #207

I see this a lot in Bellingham and Whatcom County. Some wood is made to be in contact with soil. It is sold that way. This is referred to as preserved wood or pressure-treated lumber. The fact of the matter is that not all pressure-treated lumber is created equal. I have seen pressure-treated posts that were completely rotted away at the soil level after less than ten years. Then, personally, I have pulled pressure-treated fence posts from the ground, 20 years after planting them, and the below grade wood was as sound as the day I put them in the ground. It can be hard to predict.

But, there is one fact that is not so hard to predict: If you start with pressure-treated lumber and you make sure it is NOT below grade in critical applications, then it will probably outlive you. Obviously, in some non-critical locations like fence posts, put them below ground and hope for the best. But when I find posts that support high decks or posts that are under homes, but the posts are below grade, then I recommend that the soil be graded back from the wood. And that applies whether the wood is preserved or not.

 

Some wood is made for soil contact but, in cases where soil contact is not mandatory then, for goodness sakes, try to get the dirt back off the wood. It just makes sense.

Thanks for stopping by,

Steven L. Smith

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Posted by

Steven L. Smith

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Sussie Sutton
David Tracy Real Estate - Houston, TX
David Tracy Real Estate for Buyers & Sellers

If the wood is treated for soil contact but not a good grade level and you have to keep the soil back...what supports the wood to begin with? Concrete? Just wondering.

Nov 04, 2010 05:37 AM
Lizette Fitzpatrick
Lizette Realty - Richmond KY - Lexington, KY
Lizette Realty, Lexington KY MLS - Kentucky Homes

Unfortunately this is a very common problem. I guess things could be worse and you could own a house on water...like Venice.

Nov 04, 2010 06:08 AM
Jack Gilleland
Home Inspection and Investor Services, Clayton - Clayton, OH

I see it all the time on decks Steve.  How hard can it be to pour the concrete all the way to grade? 

Nov 04, 2010 06:50 AM
James Quarello
JRV Home Inspection Services, LLC - Wallingford, CT
Connecticut Home Inspector

My understanding is some pressure treated wood is made for ground contact and some is not.

Nov 04, 2010 03:16 PM
Steven L. Smith
King of the House Home Inspection, Inc. - Bellingham, WA
Bellingham WA Home Inspector

Yes,

There are different grades of pressure-treated lumber or so-called rot resistant wood. Some are better than others and some that are sold for ground contact still rot given a few years. Even pressure treated lumber is best when it is not in the soil but, for some applications, it is pretty much essential that it be in the ground -- like fence posts for example.

Nov 04, 2010 03:57 PM
Jay Markanich
Jay Markanich Real Estate Inspections, LLC - Bristow, VA
Home Inspector - servicing all Northern Virginia

What support would just rest on the ground or concrete and still be a good support?

Here a deck or porch must be sunk 24" minimum, depending on the weight of the supportee.  What is that column up there supporting?

Nov 05, 2010 04:14 AM
Charles Buell
Charles Buell Inspections Inc. - Seattle, WA
Seattle Home Inspector

Steve, I have seen a huge difference in the ability of treated wood to withstand rot conditions.  On the East Coast where treated wood is usually yellow pine that takes the treatment process very well is far superior to the species that are used for treated wood here on the West coast----it just does not penetrate very well.  Any treated wood that is to be actually buried should be "foundation grade"  not just "ground contact grade."  The average builder/homeowner has no clue of the difference.

Nov 05, 2010 05:40 AM
Steven L. Smith
King of the House Home Inspection, Inc. - Bellingham, WA
Bellingham WA Home Inspector

Mr Charles,

I could not agree more. PS, is yellow pine what toothpicks are made of?

Nutsy

Nov 05, 2010 09:11 AM
Steven L. Smith
King of the House Home Inspection, Inc. - Bellingham, WA
Bellingham WA Home Inspector

Jay,

I do not recall what it is on, it is an old photo in my library. Here, half the time, they simply set the piers on the earth with no footings below. Not good but often done. Also, around here, you might find that if you dig all the dirt back, there really is a footing down there but who knows.

Nov 05, 2010 09:22 AM