Cedar & Ground Contact - How does cedar hold up?

[Julie Moriarty]

I made some modifications on our back deck and had to redo the railings. I decided to do it in cedar. While cutting the posts that will fit at the bottom of the steps I realized as much as 2" of the bottom will be in contact with the ground. The bottom of the post would be in contact with paver base and the side with topsoil.

I've used PT lumber specifically rated for ground contact without any problems, but cedar? I'm worried it will rot, even with so little ground contact. I've thought about laying some small cobblestone around it. Cobble would blend in with the pavers. But over time I know dirt would silt in.

Is there a way I can use these posts without worrying about rot? They are already cut and routed and nicely match the ones at the deck level. Or do I need to put PT posts in?

[Peter Aeschliman]

I had some cedar siding touching dirt for a winter one year... had to be replaced the next summer. Cedar does have good weather resistance, but not as good as pressure treated lumber. So I would avoid the situation you describe if you can. It may last you a few years, but i assume you'd prefer it to last longer than that!

PS- I live in the Seattle area where there's lots of precipitation in the winter and not much snow. Your experience in Chicago will probably vary!

[Mel Fulks]

Don't know whether you are referring to western red cedar or Virginia cedar .Niether of which is a true cedar. The trouble with these things is partly the way the stuff is graded. Most of the grade specs say that sapwood is not a defect,even though it is totally unfit to be used outside unless treated. Never mind that most buy it for exterior use. Same thing with Douglas Fir,which most botanists say is not a true fir. See a trend here? I rip off all sapwood and discard it, have been reprimanded at times. But I will not use it. You could put pressure treated in ground and cover it above ground with a shimmed out architectural shell.

[Mel Fulks]

I see now the posts are all done .Think I would trim them about 3 inches and polyurethane glue pt blocks on them and stain the bottoms a little on the dark side , better too dark at bottom than too light. Crude but effective .

[Erik Loza]

Not sure which species of cedar we get here in TX (western, I assume? I think that's the common one..). In any case, I would definitely NOT use it for ground contact. Green-treat would be my choice. As others mentioned, you could trim out your posts with cedar or whatever, my experience is that when it cedar is in contact with dirt, it deteriorates surprisingly quickly.

Best of luck with your project,

Erik Loza
Minimax USA

[Kevin Bourque]

Cedar will not hold up to ground contact exposure. I don't even like to use it in shady locations above ground. It's a highly overrated exterior wood IMO.

[Todd Burch]

These discussions are always so interesting! Here is Texas we have eastern red cedar (not western). There are houses around (in the country) that have sat on cedar "stumps" used as piers for over 100 years. The one house foundation I am picturing in my mind right now (Chappell Hill, Texas) is pretty wavy, but it's not because the cedar is rotting, but because the ground has moved quicker than the cedar has deteriorated over the last 100 years.

[Mel Fulks]

Again,it is helpful to know what we are calling cedar. There are lots of cites of the juniper we call cedar lasting a very long time in contact with the ground and under it. Some are grave related ,coffins and markers.But it's old growth heart. A good source for rating woods and differentiating among sap ,heart , and old growth heart is the book WOOD AS AN ENGINEERING MATERIAL. Your tax dollars at work.

[Gary Herrmann]

I've got a cedar fence. Posts are cedar. 4 years old and it's holding up fine.

[Philip Berman]

Funny, I just posted about using pressure-treated.

I purchased a fence from Walpole Woodworkers in Massachusetts about 12 years ago. They were very very expensive, and when I questioned why, was told "it's white cedar, it'll last forever". I bought the fence(and the explanation, clearly). This year I contacted them when half the fence began leaning forward at a 30degree angle and having determined that the fence posts(6x6's) had rotted. Everything on the fence was white cedar. First words out of their mouths? "Nothing lasts forever, you need a new fence". Doing it myself this time since their 'forever fence' is now over $500 per foot. Live and learn. Oh, and the 'forever fence' doesn't actually come with a written warranty, but it'll last forever 'cause the salesmen said so, hence the cost. Right.

Phil

[David Helm]

Western Red Cedar, while somewhat weather resistant (old growth, heart wood only), is not for ground contact. It will rot within a few years. Way too expensive for short life.

[Brent DenHartog]

Another "no" vote from me. I had a porch railing and a mailbox post in ground contact both made from whatever Menards in the midwest calls cedar. They both rotted in <10 years.

I think cedar probably works ok as an outside wood, but once you put it in continuous contact with wet dirt it is destined to rot. Maybe if you want to improve your odds you could surround it with pea gravel or something else that would drain.

Just to explain how a porch railing was in ground contact: The posts for the porch railing had a half lap like notch cut in the bottom where the notch sat on concrete and the rest extended into the ground and was bolted into the side of the concrete. Then they back filled up to the level of the concrete.

[Todd Burch]

I just happened to be driving through Chappell Hill today - and swung a U-Turn to take a picture of the building I referred to earlier.

[Erik Loza]

I just happened to be driving through Chappell Hill today - and swung a U-Turn to take a picture of the building I referred to earlier.

Hi Todd,

In your photo, those posts look to me like Juniper rather than cedar. Like, the local (at least to us Texans...) "cedar" that is actually a species of juniper. The juniper seems to be a lot more durable stuff than true cedar (I'm originally from California and used to Cedar being tall, straight trees, not unlike Ponderosa Pine, for example). Any thoughts on that?

Erik Loza
Minimax USA

[Todd Burch]

I call it red cedar, same as eastern red cedar. This site calls eastern red cedar and juniper the same tree:
http://forestry.about.com/od/treeide...y_id_cedar.htm