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concrete footing sizing

Posted: Thu Jul 03, 2014 10:29 am
by teul2
Need some help. I am getting ready to build a deck on the back of the house. To make it match the style of the house, we are going to make the exterior pilings brick and I need some help figuring the footing size for these. Deck will be 32x16 and have 6 pilings in brick (the 3 interior will be 6x6). The brick column / pilings will be about 12in x 12in or 16in x16in depending on how we decide to stack them for the look we want. We are going to put a load on this thing before it is over with. So it needs to be strong.



What should my footing dimensions be? 2ftx2ftx2ft seems WAY to big (works out to 14 x 80lb of concrete each).

Re: concrete footing sizing

Posted: Thu Jul 03, 2014 12:12 pm
by Anatidae
It doesn't need to be that deep.

I'm not structural engineer - but My gut feeling is 24"x24"x12" with a re-bar mat 3" off the bottom and one at 3" from the finished concrete surface. Each mat is #5 rebar @ 8"o.c. both ways with 100% tie (every intersection) with a minimum clearance (off the perimeter) of 2".......(i.e., 24x24 hole = 20" long rebar). You can hold the bottom mat off the dirt with concrete bricks (not whole bricks, though) or concrete block pieces. You could actually probably get by with 1/2" rebar mat in the top.

Just make sure your bearing soil is stable. If it's clay, then over excavate the hole and fill with compacted sand, then back-fill perimeter of these 'spread' footings with sand. You pack sand either with water or vibration (or both). If done with water, you have to have a way for the excess to run-off......or wait for it to evaporate. Otherwise just wet the sand and tamp it. You don't want it to be 'slushy' or 'pumping'......(like jiggling when you tamp it)......just damp.

You might even stick a few upright dowels (1/2" or 5/8") out of your piers (sticking up into the brick pier core) that you can grout around after you lay your brick pier.

Otherwise call Bill Sheppard :mrgreen:

Re: concrete footing sizing

Posted: Thu Jul 03, 2014 2:11 pm
by novacaine
Why don't you just pick up the phone and call me???????????????? I will actually make a site visit for a cold beer..........

Re: concrete footing sizing

Posted: Fri Jul 04, 2014 10:07 am
by mfalkner
Randy is on point but at 8" center, #4 bars should do for the top. Or, holla at Bill. I'm a little out of range

Re: concrete footing sizing

Posted: Mon Jul 07, 2014 7:59 am
by chopper30

Re: concrete footing sizing

Posted: Mon Jul 07, 2014 8:07 am
by teul2
Ya can't fix stupid, that's what's wrong with me.

And I think I have chickened out on this project. The footing size, precision of post placement, and laying brick on the post have me scared off since I have never done any of those. Mostly, I do not want to dig 9+ 2x2x3 foot footings by hand. Looks like I will be referring to the patio addition thread for builder references.

Re: concrete footing sizing

Posted: Mon Jul 07, 2014 8:55 am
by stitch
Just go get you a 12" x 12" "stepping stone to set your post one :-)

........probably all you need......if it sags, jack it up and put another one in place.

Re: concrete footing sizing

Posted: Mon Jul 07, 2014 9:09 am
by landscaper
Look at your local masonry supplier for "trailer pads". They're 16"x 16"x4" solid concrete blocks that are made to support house trailers. You could use a 6x6 for your piling on top of the trailer pad and just put a brick facade around it. Should all fit neatly on top of the trailer pad. A shallow base of crusher run under each pad might not be a bad idea either. Would give you a little more stability, would act as a leveling agent for the pads, and should give you a little buffer from any soil movement.

Re: concrete footing sizing

Posted: Mon Jul 07, 2014 9:39 am
by novacaine

Re: concrete footing sizing

Posted: Mon Jul 07, 2014 11:23 am
by Anatidae
Nothing is as simple as it seems......until it fails.

Suck it up Joel - swinging that shovel will take inches off your waistline.

You can do it - Lowe's can help.

Re: concrete footing sizing

Posted: Mon Jul 07, 2014 3:08 pm
by kb7722
Have you considered building all out of 6x6 post and coming back putting brick around the exterior post? The bricks will serve no structural purpose. They will just be there for appearance.

Re: concrete footing sizing

Posted: Thu Jul 10, 2014 1:14 pm
by MudHog
Why not just set posts and brick around the posts? Build frame, then set posts.