Poll: How do you feel about pressure treated posts set in ground?

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  1. #1
    Join Date
    Mar 2009
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    Question Fill around support posts

    I'm replacing some rotten support posts under our mudroom (formerly a porch, that someone enclosed years ago), which sits 3-4' above ground. After I've replaced the supports we will be regrading the yard, filling in that area 3-4' deep and covering the new posts.

    http://gallery.me.com/ramatsu#100123...&bgcolor=black

    1) I'm pouring footings on top of untouched ground, but I'm concerned about lateral support from the fill. I won't have room to get a compactor around the posts underneath the mudroom. Should I fill that area with gravel or other rock-based product for sufficient lateral support?

    2) I'm torn between pressure treated posts (attached to galvanized saddles set in the footers) vs. concrete tube pillars. I'm not a big fan of creating problems for someone 20 years down the road when the pressure treated posts need to be replaced. If the answer to question 1 is "use gravel or rock," digging out those posts could be a real nightmare. But the tube pillars are more work and money.

    Any thoughts would be very welcome!
    Last edited by ramatsu; 08-13-2009 at 06:08 PM. Reason: Link not working

  2. #2
    Join Date
    Mar 2009
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    1,387

    Default Re: Fill around support posts

    Howdy, is there a frost heave potential in your area? If so you need to make your footer below the depth of freeze in the soil. Here is an idea i am using currantly to replace some old brick foundation that would work great for you. Dig a hole to below the frost line and drop in a cap cement block 4 by 8 by16" then set a adjustible basement screw jack ( 15,000 lbs load compasity) on it and fill the hole with cement the jack is incased and reinforces the concrete and still allows you to adjust the level of the structure.

  3. #3
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    Mar 2009
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    11

    Question Re: Fill around support posts

    We're not in a real cold zone, but since I'm going to be filling 4' up from current grade, and footings will be slightly below current grade, they will be well below frost level.

    But I am really hoping for some experienced insight about what fill material to use - earth (which I won't be able to compress, but might make the cheaper/easier pressure treated wood less hassle to replace someday) or gravel/rock for (which might ensure better lateral support, but would make it next to impossible to dig out and replace posts later, suggesting that concrete posts would be the way to go)

    Clearly, there are some advantages to doing concrete up to the eventual grade in any case, I'd just like to keep the project as simple as I can - I've already had to replace the entire rim joist system, which is a slow methodical process that's eaten up my schedule!

    Interesting idea with the screw jacks - but my friend who loaned me his probably wouldn't like them buried in concrete at my house ;-)

  4. #4
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    Mar 2009
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    Default Re: Fill around support posts

    Howdy again, the screw jacks( available at the box sotres, lowels or home depoe or on line) are not what your have in your photo gallery but are two pipes that bolt together with a adustment screw on top that allow various hieghts from the bolt patterns and lenght of pipe. Otherwise i'd install a spread footer and a stem wall- using the styrafoam block for the stem wall as your small area would not inflict allot of cost... the laterial loading of the soils would be addressed by reinforcing the concrete stem wall with 1/2 rebar.

  5. #5
    Join Date
    Mar 2009
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    11

    Default Re: Fill around support posts

    Ah, I think I get it - of course, if i want to embed the screw jacks in concrete, I'll have to build forms or use tubes since it's all above current grade level except for the footing. I haven't been able to find those screw jacks you describe at our local big box stores, so I guess I'll run out and see if some of the professional contractor supply places might have them.

    I'm actually not as concerned about the leveling part as I am about kind of fill I would need for adequate lateral load for the posts. But it sounds like in any case your recommendations both use concrete, as opposed to burying pressure treated. Because I'm thinking my choices are pressure treated posts (on a spread footing) in uncompacted soil vs. concrete posts or stem wall in gravel.
    It sounds like you are recommending a third alternative, concrete of some kind to provide lateral support independent of the kind of fill, in which case the uncompacted earth would work.

    Thanks for the input, I might have to bite the bullet and start building some forms just for peace of mind :-P

  6. #6
    Join Date
    Mar 2009
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    Default Re: Fill around support posts

    Howdy, consider having a concrete company come an give you a bid and pick the contractors brain for ideas. A stem wall on top of a footer is a conventional cement foundation. It us usually reinforced with rebar to contend with any laterial loading of uncompacted or compacted soils. The repair would be a one time fix. Wood posts isolated from water and soil will have a very long life. But in my experience not posts exposed to soil and water....
    If you check the warrantry on the pressure treated posts it only replaces the post cost if failure occurs not the labor to remove an replace....

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