Return to the Home Repair Forum | Post a Follow-Up

Fill around support posts - dirt or rock?

Posted by ramatsu (My Page) on
Thu, Aug 13, 09 at 17:53

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.

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!

Follow-Up Postings:

RE: Fill around support posts - dirt or rock?

I admire the thought you have given what you are planning to do and surely wish I could be more positive on the wooden posts.

Without adequately compacting, neither dirt nor rocks will give lateral support. The pressure treated posts if used should be rated for ground contact. Not all pressure treated wood has that rating.

Would the wooden posts conform to local codes? I'm assuming a permit isn't pulled since, at least in my area, the support means would be spelled out and subject to approval. Anything 3' or over would require approval also, any buried lumber would not be an acceptable means of support on a permanent structure.

From vibration and movement during use and depending on the type of soil, the dirt will either compact itself or open the hole to the point there is no soil contact on the posts (clay soil for example).

RE: Fill around support posts - dirt or rock?

Just a suggestion.
If allowed by AHJ, think about steel posts-pipe- plenty of support, if wrapped with suitable product, corrosion wouldn't be a problem 'til you've mouldered.
You'd want to use a soft fill to avoid damaging protective wraps.

 o Post a Follow-Up

Please Note: Only registered members are able to post messages to this forum.

    If you are a member, please log in.

    If you aren't yet a member, join now!

Return to the Home Repair Forum

Information about Posting

  • You must be logged in to post a message. Once you are logged in, a posting window will appear at the bottom of the messages. If you are not a member, please register for an account.
  • Please review our Rules of Play before posting.
  • Posting is a two-step process. Once you have composed your message, you will be taken to the preview page. You will then have a chance to review your post, make changes and upload photos.
  • After posting your message, you may need to refresh the forum page in order to see it.
  • Before posting copyrighted material, please read about Copyright and Fair Use.
  • We have a strict no-advertising policy!
  • If you would like to practice posting or uploading photos, please visit our Test forum.
  • If you need assistance, please Contact Us and we will be happy to help.

Learn more about in-text links on this page here