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what_now

Repairing rusted steel posts in crawl space

what_now
9 years ago

I also posted this on the Home Repair forum - wasnt sure best place.

The house I am buying was built in 2000 in the mid south (non coastal). Its built on crawlspace and all of the steel supports are rusting at the bottom. This is due to the design of the crawl. The builder put trenches in to drain any water out (lot slopes front to back). Sadly, the steel posts sit in the trenches. The general inspector noted "Monitor Condition". There are no cracks or settling evident.
However, I had a structural engineer out for some remodeling plans and had him look. He said its an issue, not huge, but should be repaired.

He suggested drilling a hole through the steel high above the water line and putting a bolt through and then pouring concrete around. Or cutting the steel post high, pouring concrete footer and then bolting the post to concrete.

Do these sound like good ways to deal with this? I was leaning towards the first option of drilling a hole through and adding a bolt and concrete around. And any suggestion on how this should be done? What type concrete and bolts to use? How much concrete and do I make a form for each first? I have done a lot of diy projects and this seems like it should be straight forward but its not something I am familiar with.

Comments (3)

  • worthy
    9 years ago

    Actually, I like the second approach. But it would require welding on a base plate to the existing columns, then bolting the plate to the new concrete with expanding anchor bolts.

    In both approaches, there should be some tie-in of the new concrete into the existing footings. Just resting new columns on top of the old ones does nothing to resist lateral forces.

  • what_now
    Original Author
    9 years ago

    Hmm. Not sure that would be within my diy skills. If I hire someone I want to make sure they are doing the job right. How would be best to tie the new concrete in? When looking at the posts I do not see any concrete but it could be there as there is black plastic covering the dirt of the crawlspace. I should be at the house tomorrow and can look.
    What questions should I ask any contractors to ensure they are going to do the job correctly?

  • worthy
    9 years ago

    Typically, rebar would be epoxied into holes drilled in the pads; then you install forms for the new column pours. (Properly sized Sonotubes would be easiest to use.) You can mix the concrete yourself; the bagged products can be used, but be sure to follow directions to obtain sufficient strength.

    When I've needed as little a yard, I've called ready mix companies, then met the mix truck where they're pouring a foundation. They turn the spout on the truck and fill my plastic lined utility trailer.

    But this only works if you're not far from your site and can move quickly. Otherwise, you'll end up with a solid block of concrete in your trailer!

    It's like many home construction jobs: a combination of hard dusty work in cramped areas but that still requires precision and foresight.

    Note: you can pick up the steel plates at a steel fabricator. And since the pads will be under water at times, I'd use epoxy coated rebar to tie the new concrete to the old.

    This post was edited by worthy on Mon, Apr 7, 14 at 0:27