# Slab for brick column.. What would you do?



## InspectorZo (Apr 19, 2013)

no drain blues said:


> Hey guys,
> 
> 
> Getting ready to have my brick mason set 2 brick columns (16x16) approx 5 feet tall. These columns will be on each side of a wide walk way approaching my house. Between the columns will be a metal gate. I have elected to pour the slabs, and hire out the masonry. The mason is tied up on another job and can't come by for input, until next week. So i figured i would try and get some feed back and brain storm before then.
> ...


Hey,
Where's the attached picture?


----------



## stadry (Jun 20, 2009)

hired out the foundation work ? any competent diy-er's wife ,,,,,,,,,,,,,,,,,,,,, nevermind,,, so you want a 4" sidewalk supporting 1/2 the column & the other 1/2 supported by conc ' 8-12 inches deep ' ? ? ? is that what you have in mind ? that should be issue enough for anyone :yes: 

it seems many times, we don't actually read what others write OR even what we write outselves,,, maybe there's a difference 'tween reading, comprehending, & ' really understanding ',,, communication is so difficult these daze :huh:


----------



## no drain blues (Feb 7, 2010)

Had trouble attaching the picture earlier.

Basically, is it recommended to tie a footer into an existing slab and have the brick column 1/2 on an old slab and 1/2 on new? Or is this inviting settlement issues in the future?

Thanks!


----------



## Willie T (Jan 29, 2009)

Why have it half on, and half off anything? If you have the room, keep it all off the sidewalk. Remember, this is going to be 750-800 pounds per column... and it could be more if you completely fill it with concrete and put a cap on top. Then you have the weight and torsional and rotational pressures of the gates. What do YOU think is going to happen to that little section of unsupported sidewalk?


----------



## no drain blues (Feb 7, 2010)

I see your point Willie and those are my exact concerns.

The reason I want to do this is to minimize the distance between the columns and have a reasonable gate width. 

Thanks for your input.


----------



## Willie T (Jan 29, 2009)

no drain blues said:


> I see your point Willie and those are my exact concerns.
> 
> The reason I want to do this is to minimize the distance between the columns and have a reasonable gate width.
> 
> Thanks for your input.


You COULD cleanly cut out a square about a 1/2" larger than the column will be, and dig out/pour a foundation. Then build the column all the way, directly from the surface of the foundation pad, up through the cut out hole.

But for looks, I would either keep the column all off the walkway, or all on (through) the walkway. I think half-and-half is going to look odd.

Of course, cutting a corner out like that is going to sacrifice the support the existing thickened edge now provides. But, no one will be driving close to that column, anyway, right?


----------



## InspectorZo (Apr 19, 2013)

I agree with Willie. Half and Half doesn't even make sense in my coffee let alone in hardscape design. Also, spend the extra time and a little more money and make a footing for this column. It will be heavy and cause settlement issues in the future for you. Placing the weight of the column on the edge of a 4" (possibly unreinforced) concrete slab is not wise. It's like painting over a dirty wall...
When the settlement starts, it might create a trip hazard in your walk but more importantly it will immediately affect the operation of the gate.
I vote for footing under the column (12" or so deep matching the size of the column).
Good Luck! :thumbsup:


----------



## no drain blues (Feb 7, 2010)

Thanks for info guys.

Going completely off the walkway does sound more robust. I can make up the additional width with a wider gate. 

If I do go with a new footer, what are your thoughts on tying to existing walk with rebar? I have a rotary hammer, shouldn't be too big of an issue. Will this help minimize settlement or create more force against (and potentially cracking) the thinner walk?

Cross section view.


----------



## Fix'n it (Mar 12, 2012)

looks to me that that column is doomed. the footing is nowhere near large enough. jmo


----------



## Msradell (Sep 1, 2011)

The best solution may be to cut out a strip all the way across your sidewalk about 2' wide and make a continuous slab for the 2 columns. That would provide a much more stable foundation for the columns and the large area would certainly reduce or eliminate any settling issues. I wouldn't pin into the existing sidewalk. If anything, did start to move it would just crack the sidewalk anyway.


----------



## Willie T (Jan 29, 2009)

That footing pad should be at least 30" square. No way should you make it only the size of the column.
Concrete's cheap. If it were me, the pad would be 36" x 36", and 12" thick... and it would have 4 # 5's going both directions.


----------



## no drain blues (Feb 7, 2010)

Willie

If I go your method with a larger pad, I obviously don't want the entire footer all the way flush with current walkway etc. so that it's visible.

Should this be brought to a few inches from surface, then brick on the sunken footer so the first run of brick are "under ground" resting on the footer? Or, do two pours... one the larger sunken footer, then smaller (column size) footer on top to get flush with the height I want the first layer of brick to start?


----------



## GBrackins (Apr 26, 2012)

you need to remove the top and subsoils which typically are not suitable for supporting structural loads. so obviously the bottom of the footing would be lower than what is shown in your photo.

lets run some rough numbers. brick column 16"x16" filled with concrete to anchor the brick and the gate.

1.33' (16"/12" per ft) x 5' high = 6.67 s.f. x 4 sides = 26.67 s.f. of brick x 40 psf (weight of brick) = 1066 lbs. 

16" column width - width of brick on two sides (3" wide brick) leaves 10" for the concrete column

10" x 10" x 5' = 0.83' x 0.83' x 5' = 3.47 cu.ft of concrete x 150 lbs/cu ft = 520 lbs.

total weight = 1066 lbs. + 520 lbs = 1586 lbs. lets say your gate weighs 114 lbs to make things simpler then your total weight is 1700 lbs per column.

I'd recommend the footing extend a minimum of 4" beyond the column (16" column + 4" + 4" = 24") for stablility and support a 2'x2' footing covers 4 s.f.

1700 lbs / 4 s.f. = 425 psf. which your soil should be able to support as long as it's not disturbed or organic in nature. with your footing being lower than the bottom of the slab the footing can extend under the existing slab. Make sense? Now with me being a wimp I'd probably use Willie T's 30" x 30" footing because bigger is better and would provide lower psf and more stability, besides concrete is cheap.

in my area we'd have to extend the bottom of our footing til it was 48" below the adjacent grade for frost protection to prevent frost heave from toppling everything so consider yourself lucky being in Texas


----------



## no drain blues (Feb 7, 2010)

Wow! Thanks for all the great info! 

It makes sense to me when you say go under the current slab with the footing. 

I'm I understanding you correctly: the finished height of the footer should be "below grade"? For example the surface of the footer should meet approximately the base of the current slab? 

The first run of bricks will be below grade?


----------



## GBrackins (Apr 26, 2012)

you'd have to excavate to determine where your good undisturbed soil is located. I'd say probably a couple of feet. you want part of the column below grade with your footing. This way the back fill will help to stablize the column. the larger the footing the more stable it will be. stop and think, if you try and push down on one side of the footing the dirt on top of the other side will help to resist that movement. you'll need steel reinforcing that extends from the footing pad up into the column to tie it all together. hopefully your mason is knowledgeable about building columns. Have you asked them if they've done this before and went to see their work? I would .....

yes the top of the footing should be below the surface of the ground. if you excavate two feet of fill and your footing is 12" that would leave 12" of fill on top. do not tie your walkway to the footing or columns.


----------



## Willie T (Jan 29, 2009)

no drain blues said:


> Wow! Thanks for all the great info!
> 
> It makes sense to me when you say go under the current slab with the footing.
> 
> ...


The finished height of a non-basement house footer is well underground, right? At least 12". The first three runs of brick below ground.


----------



## jomama45 (Nov 13, 2008)

You can leave the first few bricks below grade, just make sure the weeps are above grade (assuming the mason is using them). You'll want at least 6" of ground over the footing to plant grass flowers, etc... and get them to grow.


----------



## Fix'n it (Mar 12, 2012)

if i were doing that = 

5' deep x at least 2' hole. NO sono-tubes ! just a hole. fill it with concrete. and have rebar coming up at least 2' above grade.


----------



## no drain blues (Feb 7, 2010)

Thanks for all the advice everyone.

I got the footers done over the weekend. I went close to 36"x36" and almost 24" deep with some 5/8 rebar in there. I stopped a few inches from the surface so about two courses of brick will be below grade.

I decided not to do the extra rebar running vertical to support any filling as this will be a hollow column. The gate I mentioned will not be attached to the columns, it will have it's own metal hardware and supports separate from the brick. 

If all goes well bricking will happen towards end of week.


----------



## GBrackins (Apr 26, 2012)

post some photos when you're done please


----------



## Michele1 (May 26, 2013)

I am getting ready to build 3 bricks columns on my 4inch concrete patio. I would like to know will the 4inch concrete hold up the brick colums?


----------



## Willie T (Jan 29, 2009)

Michele1 said:


> I am getting ready to build 3 bricks columns on my 4inch concrete patio. I would like to know will the 4inch concrete hold up the brick colums?


Do the little 4" bricks (with no steel in them) hold up all the bricks above them? What a load on that first bottom row of bricks!

The trouble comes when you plan to simply build a column on the edge of that slab. The object and function of a pad is just like your own feet... to spread the load of the weight of the body. Spread it out some so the column doesn't exert all its pressure straight down below it. (Imagine walking on just 3" diameter stubs at the ends of your legs.) The concrete in the pad doesn't give way...... the ground below it does, IF the weight is not spread out some... in ALL directions.

"But I'm putting the columns out in the center of the slab... That's certainly spreading the weight out." Think about it. There is a reason you are required to dig the bottom of a footing down to "undisturbed" soil. That is because dirt settles. And that dirt way down in there has been settling for decades. It's packed good. Solid! Not so for the layer of dirt just below your 4" slab. Sure, "compacting" it helped some. But compacting is not all that effective.... especially not the way it is done by the sobered-up drunk they hired to run the little "shaker machine" for a few minutes.


----------



## no drain blues (Feb 7, 2010)

Ok GB here they are so far. 

I had the mason leave the top off for now. I want to run some electrical incase I want to light them in the future.

I'm thinking I might have them re-do the top two courses. I'm not in love with the sliver cuts they did. But the columns are true and solid.

The distance between the two columns is 66 inches. I'm struggling with what to do about the gate situation that will be between the columns. I'm having that built to my specs, but not sure if I want a monstrous 5 foot gate. Thoughts?


----------



## GBrackins (Apr 26, 2012)

looks good!

do a double gate, less weight on each set of hinges. could have a pin (into sidewalk) so that one side opens and the other stays fixed unless you pull up the pin.

of course if I was hanging metal gates off the columns I'd have concrete in the void area to anchor the hinges into


----------



## no drain blues (Feb 7, 2010)

I kind of ruled out a double gate bc. I think it might be less secure than a single...


I'm leaning towards a 2 foot fence piece then 3 foot gate. Between the 2 foot piece and the gate will be a static post (bolted to walk). Not sure how that would look, but it would cut down the overall width.


Btw. I'm not planning on hanging the gate directly to the columns. I didn't mention this earlier (I wanted to avoid being lambasted), but I allowed space for steel gate posts when I built the footers. I cut the slab (covered by wood in and brick in photo) and put a 8" tube and poured the footer around so I can install the steel posts later. I didn't want the posts in the way of the masonry.


----------



## Willie T (Jan 29, 2009)

A 2 foot fence is "security"?


----------



## no drain blues (Feb 7, 2010)

2 foot wide. Hard to explain. I'll sketch it out and post it up later.


----------

