Lally Column Footing And High Water Table - Building & Construction - DIY Chatroom Home Improvement Forum


Go Back   DIY Chatroom Home Improvement Forum > Home Improvement > Building & Construction

CLICK HERE AND JOIN OUR COMMUNITY TODAY...IT'S FREE!

Reply
 
Thread Tools Display Modes
Old 10-31-2010, 10:40 PM   #1
Newbie
 
Join Date: Dec 2008
Posts: 8
Rewards Points: 10
Default

Lally column footing and high water table


I'm putting in a couple additional lally columns in my basement. I'm going to pour 2'x2'x12" footings for them to rest on, so I cut 2'x2' openings in the slab. My intention was to square out the hole and let the surrounding soil be the form.

My issue is that I'm running into a high water table and there is about 7 or 8 inches of water in the holes. I can pump them out, but they fill back up pretty quickly.

What are my options for pouring? Dewater as much as I can and pour?

Also, should I excavate further and add crushed stone underneath? Digging in the water has made it difficult to acheive a nice level surface.

Thanks for any ideas/advice.

Advertisement

mlitcher is offline   Reply With Quote
Old 10-31-2010, 11:03 PM   #2
Civil Engineer
 
Join Date: Mar 2009
Location: Boston
Posts: 4,309
Rewards Points: 2,196
Default

Lally column footing and high water table


For purposes of this discussion, I am going to assume you have adeqaute basis for the size of the footings, the number of columns, and the location of the columns. So let's discuss concrete placement alternatives.

Option 1: You dewater the hole using a sump pump, or well point near the hole. This allows you to prepare the footing base properly, and place concrete normally. Of course, you need to keep the pump running during the preparation of the hole, although not necessarily during placement of the concrete (see option 2).

Option 2: You place the concrete underwater, using tremie technique. Since the hole will be full of water when you place the concrete, it will be difficult to properly prepare the hole, but there will be no problem placing the concrete if you get the proper mix.

Option 3: You place a waterproof form in the hole, and dewater by pumping out the form. The form could be a steel or other metal box, or even plastic. As long as you get a good seal on the bottom, pumping out the hole should be easy, and it should stay dry long enough to place the concrete. This will allow you to adequately prepare the base of the footing.

There are more exotic techniques for doing the job, such as preplaced aggregate, but they should not be necessary for such a small project. As noted, all of this assumes that the size and depth of the footing is adequate to support the column you intend to place.

Advertisement

Daniel Holzman is offline   Reply With Quote
Old 10-31-2010, 11:52 PM   #3
Newbie
 
Join Date: Dec 2008
Posts: 8
Rewards Points: 10
Default

Lally column footing and high water table


Thanks for such a quick reply. I appreciate it.

If I went with option 1, after I quit pumping, do I need to be concerned about the groundwater surrounding the footing and the concrete absorbing any of it? Or would it just simply increase the curing time?

Thanks again.
mlitcher is offline   Reply With Quote
Old 11-01-2010, 01:01 AM   #4
Member
 
jlhaslip's Avatar
 
Join Date: Dec 2009
Location: Canadian Rockies
Posts: 1,280
Rewards Points: 500
Default

Lally column footing and high water table


The longer it takes to 'cure', the stronger the concrete is.
Slabs are often kept wet to improve them. Your pour should be in good shape.
__________________
Quote:
Originally Posted by Bud Cline View Post
Go ahead and apply for a variance, those guys at City Hall can use a good laugh.
jlhaslip is offline   Reply With Quote
Reply

Tags
high water t , lally column


Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Similar Threads
Thread Thread Starter Forum Replies Last Post
Sump pump pit water level --- problem de12 Plumbing 49 02-27-2011 02:42 PM
New basement in high water table eds1618 Building & Construction 11 09-30-2009 07:12 PM
Stumped: Basement water and fix- Did I make things worse? jws3 Building & Construction 27 10-16-2008 08:38 AM
Rain water draining into sump pit ERIK2173 Building & Construction 19 07-20-2007 10:19 PM




Top of Page | View New Posts