Replies

1. 
   Piffin | Oct 17, 2008 04:51pm | #1

   Your home is likely to fall down before thos posts rot.

    

    

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2. 
   Mongo | Oct 17, 2008 05:28pm | #2

   Agree with the Piff-meister.

   For termites, if it's a concern you can add a shield to the tops of the posts, or kerf the perimeter of the post and add a small piece of angled-down flashing.

   As far as digging around the posts, you could have an exterminator come in and inject the subsoil around the posts.

   The only reason I'd dig down was if the sunroom was settling, meaning the posts are sinking.

3. 
   DanH | Oct 17, 2008 05:31pm | #3

   Pouring concrete around the posts will make them rot faster.

   If you feel compelled to do something, dig around them and then refill with crushed rock. It will drain better than soil and help keep the posts dry.

   Corporation: n. An ingenious device for obtaining individual profit without individual responsibility. --Ambrose Bierce
4. 
   Dinosaur | Oct 17, 2008 06:36pm | #4

   Depending on the manufacturer of the PT lumber and the process used, those posts might be rated for anywhere from 15 years to 'lifetime'. However, you should understand that these guarantees are projections based on computer modeling and accelerated weathering tests; the products themselves have not been in commercial use long enough to know how long they will really last. (ACQ, for instance, has only been in use since 1991, and did not gain any appreciable market share until 2000.)

   If your posts are older, they are likely treated with CCA, an inorganic poison composed mainly of copper and arsenic. This type of treated lumber will have a greenish hue. If they are fairly new, they are probably treated with an organic poison known as ACQ, alkaline copper quat. Copper quat lumber has a yellowish colour.

   CCA lumber was treated with a moderate dose of high toxicity poison; ACQ uses a much higher concentration of lower-toxicity poison. Both leech poison into the surrounding soil and neither should be used in any application where human or animal skin contact can occur.

   There are also several classes of both types of treated lumber; some are rated only for above-ground use; others for in-ground use. When purchased, lumber is tagged with the type and use-rating; these tags are often lost during construction so it may not be possible for you to know what class of treated wood your posts are.

   There are serious fastener issues with PT lumber, too. ACQ is particularly corrosive to metal fasteners and only the heaviest hot-dip galvanised or stainless-steel fasteners and hangers should be used. If that is not the case for your deck, you should consider removing the PT posts and replacing them with untreated, naturally-resistant wood species (cedar; greenheart; hemlock; etc.), set on crowned concrete piers sitting at least 4" above grade.

   For more information about fastener and connector requirements, take a look at this page. (It's a pdf file, so you'll need Acrobat Reader to open it.)

   Dinosaur

   How now, Mighty Sauron, that thou art not brought
   low by this? For thine evil pales before that which
   foolish men call Justice....
   

   

   
   

   ---

   Edited 10/17/2008 11:40 am ET by Dinosaur

5. 
   user-144854 | Oct 17, 2008 11:15pm | #5

   The best course of action depends on your location and particular soil/moisture/varmint conditions.  I retired before ACQ lumber was in use, but have seen .40 CCA in ground contact rot in just a few years in the Carolinas.  Up here in Central Colorado, a piece of bread on the ground will last decades.  I still pour concrete & set posts above grade, even up here, because doing otherwise just don't feel right.

   Barring expected aggravated rot or bug problems at your site, I think I'd leave 'em alone if they ain't settling.  If anything, I'd cut them off above grade and re-do it right.  Replacing soil with concrete will probably, as mentioned, make things worse; and I'm not convinced that using gravel will help more than hurt (can lower the frost line and introduce heaving, create a moisture sump in some soils where none existed before, etc.).

   Good luck.  Keep us "posted".

   }}}}

1. 
   Piffin | Oct 18, 2008 12:48am | #7

   Well, Cariolina has four seasons of rot causing weather and tem[ps. Things do rot fast here except for about 3-4 months of winter.But I recently saw some posts pulled that were 6x6 CCA.40 I set back in '99
   They were good enough that I would use them again. Not a scrid of rot going on. I was actually surprised. And these he has are 8x8. I don'
   t know if they were ground contact or what his climate is, but I have a hard time seeing them ever rot in my lifetime. 40 CCA is what I have under my decks.But your rec is good. If he feels compelled to do anything at all, the right thing would be to support the deck, and replace the underground portion with a smooth crete pier. 

    

   Welcome to the Taunton University of Knowledge FHB Campus at Breaktime. where ... Excellence is its own reward!

6. 
   john7g | Oct 18, 2008 12:19am | #6

   They won't be an issue, like everyone else is saying as well as CC causing them to fail prematurely.  If you're still concerned about termites, get some Ortho Home Defense Max in concetrate form and follow the directions. 

   The termite/exterminator company I deal with gets concerned when they see 4x4 or landscape timbers (something about lesser quality of treat) but are pretty confident when they 6x6 and larger. 

7. 
   brucet9 | Oct 18, 2008 02:04am | #8

   "...when I backfill I can add some sort of pesticide to the soil that will surround the newly poured concrete, making it less likely that the termites will be a problem."

   What, no plutonium flakes? :)

   BruceT