Replies

1. 
   FastEddie1 | Jul 24, 2005 06:39am | #1

   It would probably be better if the board were raisewd off the ground an inch to allow water to flow under it. 

   There are a couple of grade of PT lumber, rated by the amount of preservative in the wood.  I forget the numbers.  The lowest number is for above ground use ... deck boards.  Another number is for ground contact ... fence posts.  And I think there is a third number.  Anyway, if your board is rated for ground contact, then it's ok.  With the old PT stuff, there was a small plastic tag stapled to the end of the board, and it gave trhe number ... like .40 ... and said "ground contact" or whatever.

    

   I'm sorry, I thought you wanted it done the right way.

2. 
   Dinosaur | Jul 24, 2005 07:24am | #2

   The stuff may be rated for ground contact as Ed said. I don't know what the numbers should be myself, as I resist the use of PT lumber whenever possible (there are other ways...). A lot of builders put a great deal of faith in those ratings, too. But the reality is those ratings are based on predictions arrived at by computer modeling. The stuff hasn't existed for as long as the ratings guarantee it.

   I agree with your gut feeling that gravel under the skirt boards would be a good idea. Gravel is inorganic, drains well, and dries quickly. All three of those conditions help prevent growth of mould and rot spores.

   Dinosaur

   A day may come when the courage of men fails,when we forsake our friends and break all bonds of fellowship...

   

   But it is not this day.

3. 
   AdamGreisz | Jul 24, 2005 09:36am | #3

   Pressure treating for wood used in residential construction is done to .25 pounds per cubic foot for wood that is rated for exterior use above ground (think wolmanized or similar deck joists and decking) or .40 #'s/cu. ft for ground contact uses (think mudsill's or fence posts). I believe that there are many other standards as well.

   Your lumber specifications suggests above ground use. I am not as familiar with the newer treatments (ACQ, ACZA, CBA-A or CA-B versus CCA).

   I found a recent Fine Homebuilding article about the switch away from CCA treatments. http://www.taunton.com/finehomebuilding/pages/h00127.asp

   A link inside the stories (more choices than before) gives some illumination.

    

    

   Adam Greisz

   Owen Roberts Group

   10634 East Riverside Drive # 100

   Bothell, WA 98011

   http://www.owenrobertsgroup.com

   
   

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   Edited 7/24/2005 2:39 am ET by Adam Greisz

1. 
   FastEddie1 | Jul 24, 2005 03:16pm | #5

   Your lumber specifications suggests above ground use.

   Adam that was my impression too, based on the label info he gave, but it wasn't entirely clear.

    I'm sorry, I thought you wanted it done the right way.

4. 
   goldhiller | Jul 24, 2005 09:39am | #4

   IMO.........you have another concern besides eventual and potential rot........a little thing called and known as frost-heave. Gravel would drain better and result in less heave and the accompanying stuctural stresses.

   We have a "method/materials" we sometimes use to address this sort of thing in instances similar to those you describe. If you're interested, let me know and I'll describe it for you. "Cheap and dirty"...... but it works nicely/effectively.

   PS.......Welcome to Breaktime. It would help dispensing advice if you clicked on your name and filled in a little profile info. ;-)

   Knowledge is power, but only if applied in a timely fashion.

   
   

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   Edited 7/24/2005 2:49 am ET by GOLDHILLER

5. 
   JohnSprung | Jul 26, 2005 08:52pm | #6

   You might try digging out around where the wood meets the ground, and treating it with Jasco's Termin-8.  Here in LA, I used Termin-8 on some Doug fir for a "temporary" walkway.  It's still doing fine after 33 years in direct contact with the ground.  Backfill with gravel as others have suggested.

    

   -- J.S.