Installing post footing in basement floor

Page 2 of 2  


So is there a consensus here that my proposed new footing is going to settle? And is settling to be expected even if I make it 2' by 2' as Bob has proposed?
If I jack up the beam 1/4" in anticipation of settling, the result will be damage to the structure above the beam.
If I load the new post with the beam at its current level and it settles 1/4", the result will be damage to the structure above the beam.
The existing post has rested on the slab for 75 years, and I have no particular reason to expect the slab to fail (or to settle) if I put the _new_ post on the slab. Barring a slab failure, this approach produces no damage.
So this brings me full-circle back to the issue that we were discussing last week Except now it appears that I _can_ expect damage if I pour a new post footing instead of resting the new post on the slab where the old post rested.
-Mark
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
Mark wrote:

If the footing is placed on undisturbed soil there is no reason that it would settle unless it was an insufficient, small footing.

You mentioned that the bottom of the beam had crushed fibers at the post. You should take a laser level to the floor above and see if the floor dips at the beam. If so, jack it up slowly to prevent cracking. About 1/16" per day should minimize cracking. If it hasn't settled and you don't need to straighten out the floor, then just jack up the beam enough to take the load off of the post and maybe a bit more. 1/8" is all you need. Again, this should be done slowly to minimize cracking - particularly if the house has plaster walls and tiled floors above.

It shouldn't settle.

My original advice was to saw cut the slab and place the footing on top of it. The footing would not have to be quite as large nor deep if it were on top of the slab. Build shelves around the post on top of the footing if you'd like.

If you continue back full circle, check out my advice on placing the footing on top of the slab. Thanks.
R
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
In a previous post Mark wrote...

No. As I just said a properly sized footing on undisturbed glacial till will not settle.

Raise the beam to level + a little. 1/16"-1/8" would be plenty. This has nothing to do with settling and everything to do with being able to install the new post cap.

Still doesn't make it the right solution. If you do the work properly and carefully there will be no damage to the existing structure.

No. Wrong answer. If you don't want our advice then don't post questions. I have given you a solution that has worked many times with no damage to the existing structure. If you don't want to take the advice, then don't. Just don't complain when you have problems down the road.
Overall, I think you are obsessing over this too much. If you had shored the beam, cut the hole, and poured the concrete last week, you would now be done with the project.
--
Bob Morrison, PE, SE
R L Morrison Engineering Co
  Click to see the full signature.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

Bob, I am not questioning your advice one bit. I was just following up because someone else on the list chimed in with "It's gonna settle. . . you'd better jack it up 1/4" first." Being prone to paranoia, I thought I should follow up on that.

Oh, no doubt about that. Unless of course the 2' x 2' hole filled up with water courtesy of the current "pineapple express" we are enjoying here in the PNW. =8-o
Hmm. . .maybe I should have you take a look at it. I actually have several basement support issues that need attention. Are you interested in a few hours of on-site consulting in Seattle?
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
In a previous post Mark wrote...

That was bad advice. As both Rico and I have pointed out you want to be just above level. This is usually 1/16"-1/8"

If that hole fills with water you may have some serious drainage problems. BTW, thanks to that "pineapple express", my power has gone out 4 times since last Friday afternoon.

Probably not economically worth it for either of us. However, if you want a structural engineer to look at the situation, here is a reference list in PDF form:
http://tinyurl.com/y8s6ne
--
Bob Morrison, PE, SE
R L Morrison Engineering Co
  Click to see the full signature.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
In a previous post Mark wrote...

Totally unnecessary if you do the job properly in the first place.
A properly sized footing on a solid soil base won't settle. Certainly not on glacial till. The only type of soils that might have some movement issues would be expansive clays or soft peats. If you house is on either one of those then you have a lot more than a single footing to worry about.
--
Bob Morrison, PE, SE
R L Morrison Engineering Co
  Click to see the full signature.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

Related Threads

    HomeOwnersHub.com is a website for homeowners and building and maintenance pros. It is not affiliated with any of the manufacturers or service providers discussed here. All logos and trade names are the property of their respective owners.